Timing and duration of nutrient restriction and its impacts on placental development and umbilical blood flow in adolescent sheep

We hypothesized that nutrient restriction from day 50-90 of gestation decreases umbilical blood flow and that umbilical blood flow would recover to control values upon realimentation during late gestation (d 90 to 130) or remain reduced in ewes that continued to be nutrient restricted. On d 50 of gestation, young nulliparous whiteface ewes (6-8 mo; n = 41) carrying singletons were randomly assigned to two dietary treatments: 100% of NRC recommendations (CON) or 60% of CON (RES). On d 90 of gestation, ewes either remained on CON or RES until d 130, or CON ewes were RES from d 90 to 130, or RES ewes were realimented to CON from d 90 to 130. This resulted in 4 treatment groups on day 130: CON-CON, CON-RES, RES-RES, RES-CON. Umbilical blood flow and fetal and placental measurements were obtained via ultrasonography every 10 days from day 50-110. Non-survival surgeries were performed on days 50, 90, and 130 (n = 6-7 ewes/group) where uterine artery and umbilical blood flows were measured during surgery via ultrasonography. Conceptus weights were recorded and placentomes collected to determine binucleate cell numbers. The study was conducted as a completely randomized design arrangement with repeated measures. Data were analyzed using the MIXED procedure of SAS. There was a nutritional treatment by day interaction (P < 0.01) with CON ewes having greater umbilical blood flow compared with RES by d 90. Fetal biparietal distance, abdominal width, and kidney area increased (P < 0.05) in CON-RES with all these measurements increasing during late gestation. We partially accept our hypothesis as nutrient restriction during mid gestation decreased umbilical blood flow. However, blood flow did not return to control levels upon realimentation. By d 130, fetal and placental weights were similar between RES-RES and CON-CON. Binucleate cell numbers in the fetal trophoblast were not influenced by nutritional treatments. Our findings suggest that refeeding previously nutrient restricted pregnant adolescent ewes to control levels does not reestablish umbilical blood flow. Adequate placental development during mid gestation could protect the fetus from a decreased umbilical blood flow later in gestation when nutrients were limited by 40%.

Uterine kallikrein and arterial bradykinin activities and uterine arterial proliferation in response to acute estradiol-17β exposure in ovariectomized ewes

Estradiol-17β (E2) increases kallikrein in rodent and human reproductive tissues. Kallikrein specific activity is increased in the porcine uterus when conceptus E2 is secreted at maternal recognition of pregnancy. When kallikrein acts on kininogen to liberate bradykinin, angiogenic and vasoactive factors are released. The uterus of ovariectomized ewes administered E2 undergoes rapid vascular changes via different patterns of angiogenic and vasoactive factors. Our hypothesis was that E2 would increase the specific activity and protein secretion of tissue kallikrein in endometrial explants culture media (ECM) and ewes exposed to E2 would have uterine arteries that would be more sensitive to the vasodilatory effects of bradykinin. Ovariectomized ewes received 100 mg of E2 implants for 0, 12, 24, or 48 h. After treatment, uterine weights were determined, and caruncles were processed for ECM. Uterine weights and uterine weight per ewe body weight were significantly greater in the 12 and 24 h ewes compared with the 0 h ewes, with the 48 h ewes being similar to the 24 h ewes. There were no statistically significant differences in caruncular tissue kallikrein protein secretion among the treatment groups. There was a tendency (P = 0.09) for duration of E2 exposure to influence tissue kallikrein specific activity where kallikrein activity was greater (P ≤ 0.05) in the 12 and 48 h ewes compared with the 0 h ewes, with 24 h ewes being intermediate (unprotected F test). Uterine arteries from ewes with E2 for 24 and 48 h had more sensitivity to bradykinin, via the bradykinin receptor 2, than uterine arteries from ewes with 0 or 12 h E2 exposure. We fail to reject our hypothesis as E2 did elicit a positive response in tissue kallikrein specific activity and bradykinin response. Further investigations are needed to determine how kallikrein and bradykinin may be involved in vascular remodeling of the ovine uterus.

Plane of nutrition and FSH-induced superovulation affect the expression of steroid hormone receptors and growth factors in caruncular tissue of non-pregnant sheep

Implantation is a critical step in the establishment of pregnancy and an important part of embryo-maternal contact. Uterine receptivity can be affected by changes in body condition and the maternal endocrine milieu, including those caused by the use of exogenous gonadotropins in controlled ovarian hyperstimulation to induce the development of multiple follicles. This study demonstrates the effects of FSH-mediated ovarian hyperstimulation on the caruncles of ewes under various feeding regimes. Sheep were classified into 3 categories: control fed (CF), overfed (OF), or underfed (UF). In each group, animals were superovulated with FSH or injected with a saline solution (non-treated control). Uterine caruncles were collected at the early (d 5) and mid-luteal phase (d 10) of the estrous cycle. The transcript levels of steroid hormone receptors (ESR1, ESR2, PGR) and growth factors (IGF1, IGF2, VEGFA) were investigated and their expression localized by immunohistochemical staining. As for the main findings, day of the estrous cycle affected expression of ESR1, IGF1 and IGF2, but not of ESR2, PGR and VEGFA; both feeding and superovulation had modulatory effects, with feeding (UF/OF) stimulating expression of all genes studied, and superovulation altering expression of some genes, eg IGF1, PGR and ESR1 and ESR2, in CF animals. Similarly, feeding (UF/OF) altered responsiveness to superovulation for PGR on d 5 and ESR1/ESR2 on d 5 and/or 10. Our data emphasize possible effects of dietary and/or hormonal stimuli on uterine physiology, which may affect pregnancy outcomes by disrupting uterine functionality.

Mid- to late- gestational maternal nutrient restriction followed by realimentation alters development and lipid composition of liver and skeletal muscles in ovine fetuses

Maternal nutrient restriction during gestation adversely affects offspring growth and development of liver and skeletal muscle tissues. Realimentation following nutrient restriction may alleviate these negative impacts on development but may alter metabolism and tissue composition. Forty-eight ewes, pregnant with singletons, were fed to meet 100% National Research Council (NRC) recommendations starting at the beginning of gestation. On d 50 of gestation, 7 ewes were euthanized (BASE), and fetal liver, skeletal muscles, and blood samples were collected. The remaining animals were fed either 100% of NRC recommendations (CON) or 60% NRC recommendations (RES), a subset were euthanized at d 90 of gestation (n = 7/treatment), and fetal samples were collected. Remaining ewes were maintained on the current diet (CON-CON, n = 6; RES-RES, n = 7) or switched to the alternate diet (CON-RES, RES-CON; n = 7/treatment). On d 130 of gestation, the remaining ewes were euthanized, and fetal samples were collected. At d 130 of gestation, maternal nutrient restriction during late-gestation (RES-RES and CON-RES) decreased fetal liver weight (P < 0.01) and cross-sectional area in triceps brachii (P = 0.01; TB), longissimus dorsi (P = 0.02; LM), and semitendinosus (P = 0.05; STN) muscles. Maternal nutrient restriction during mid-gestation increased hepatocyte vacuole size at d 130 of gestation. Late-gestational maternal nutrient restriction increased mRNA expression of insulin-like growth factor (IGF) binding protein-1 (P < 0.01), glycogen synthase 2 (P = 0.01; GYS2), and pyruvate dehydrogenase kinase 1 (P < 0.01; PDHK1) in the liver and IGF receptor 1 (P = 0.05) in the LM. Lipid concentration in the LM was decreased by late-gestational nutrient restriction (P = 0.01) and increased by mid-gestational nutrient restriction in STN (P = 0.03) and TB (P < 0.01). Principal component analysis of lipidomics data demonstrated clustering of principal components by day of gestation and elastic net regression identified 50, 44, and 29 lipids that classified the treatments in the fetal liver, LM, and blood, respectively. In conclusion, restricting maternal nutrition impacts fetal liver and muscle morphology, gene expression, and lipid metabolism, whereas realimentation attenuated some of these effects. Therefore, realimentation may be a viable strategy to reduce the impacts of nutrient restriction, but can lead to alterations in lipid metabolism in sheep.

PSX-A-16 Late-Breaking: Maternal nutrient restriction and re-alimentation influences liver protein expression in fetal sheep

To determine the effects of maternal nutrient restriction and re-alimentation on the fetal liver proteome, 48 pregnant ewes with singletons were fed a control diet [100% National Research Council (NRC) requirements (CON)] starting at the beginning of gestation. On day 50 of gestation, a subset of ewes were fed either CON or 60% NRC requirements (RES). A subset of ewes were euthanized at day 90 of gestation (n = 7/treatment), and fetal liver samples collected. Remaining ewes were maintained on the current diet (CON-CON, n=6; RES-RES, n = 7) or switched to alternative diet (CON-RES, RES-CON; n=7/treatment). On day 130 of gestation, remaining ewes were euthanized, and fetal samples collected. Fetal liver proteins were extracted, digested by trypsin and subjected to multiplexed, label-based quantitative mass spectrometry analysis integrating Tandem Mass Tags. Proteins were identified and quantified using Proteome Discoverer (v2.5, Thermo Scientific) and differential abundance analysis was performed using ANOVA and post hoc Tukey’s HSD test. Hierarchal clustering analysis showed clustering of treatments by day of gestation. However, differences were also observed between treatments. At day 90 of gestation, 23 proteins were differentially expressed in RES compared with CON among which glycyl tRNA synthetase and pyruvate carboxylase were increased 12% and 10%, respectively (P &lt; 0.03). At day 130 of gestation, 24, 5, and 71 proteins were differentially expressed in CON-RES, RES-CON, and RES-RES, respectively, compared with CON-CON. Carnosine dipeptidase 2 was decreased 7% in CON-RES and rho associated protein kinase and glycogen synthase 2 were increased 20% and 26% in RES-CON and RES-RES, respectively, compared with CON-CON (P &lt; 0.04). These results indicate that nutrient restriction during mid- and late-gestation impacts expression of proteins involved in gluconeogenesis, glycogenesis, and the formation of carnosine, an integral molecule in beta-oxidation, and that re-alimentation alters proteins involved in cell migration pathways. Supported by USDA-AFRI grants 2016-67016-24884 and 2017-67016-26568.

PSV-2 Maternal nutrient restriction and re-alimentation influences liver and muscle tissue development and gene expression

To determine the effects of maternal nutrient restriction and re-alimentation on fetal liver and muscle development, 48 pregnant ewes with singletons, were fed a control diet [100% National Research Council (NRC) requirements (CON)] starting at the beginning of gestation. On day 50 of gestation, ewes (n = 7) were euthanized and fetal liver and skeletal muscle samples were collected. The remaining animals were fed either CON or 60% NRC requirements (RES), a subset were euthanized at day 90 of gestation (n = 7/treatment), and fetal samples obtained. Remaining ewes were maintained on the current diet (CON-CON, n = 6; RES-RES, n = 7) or switched to alternative diet (CON-RES, RES-CON; n = 7/treatment). On day 130 of gestation, remaining ewes were euthanized, and fetal samples collected. Fetal liver was analyzed for general tissue morphology, and fetal skeletal muscles were analyzed for lipid accumulation. mRNA expression of growth and metabolic factors were quantified in liver and muscle tissues. Hepatocellular vacuolation was increased in RES-CON and RES-RES compared with CON-CON and CON-RES (P &lt; 0.01). In semitendinosus and triceps brachii, intramyocellular lipid content increased 19% and 15%, respectively, in RES-CON and RES-RES compared with CON-CON and CON-RES (P£0.02) and in longissimus dorsi, lipid content was decreased 7% in CON-RES and RES-RES compared with CON-CON and RES-CON (P=0.01). In liver, insulin-like growth factor binding protein-1, glycogen synthase 2, and pyruvate dehydrogenase kinase 1 expression increased 1.92-fold, 1.45-fold, and 1.47-fold, respectively (P£0.03) in CON-RES and RES-RES compared with RES-CON and CON-CON. In LD, IGF1-R expression increased 3.19-fold in CON-RES and RES-RES compared with RES-CON and CON-CON (P = 0.05). These results demonstrate that maternal nutrient restriction followed by re-alimentation restores liver and muscle gene expression of growth and metabolic factors while negatively impacting liver composition and muscle lipid content potentially leading to altered tissue function and metabolism later in life. Supported by USDA-AFRI grants 2016-67016-24884 and 2017-67016-26568.

Acute effects of estradiol-17β on plasma volume and uterine cell proliferation in sheep

Ovarian steroids play an important role in increasing plasma volume in pregnant females and preparing the uterus for implantation. We hypothesized that a short duration of increased estradiol-17β (E2) would increase plasma volume and uterine cell proliferation in ovariectomized ewes. Adult non-pregnant Romanov ewes (n = 15) were ovariectomized. After ovariectomy, ewes were individually housed and were offered water at ad libitum intake and were fed a pelleted diet at maintenance once daily according to body weight. After at least 30 days post-ovariectomy ewes were fasted and received an implant placed in the axillary region that contained 100 mg of E2 (E2; n = 8) or a sham implant with no E2 (CON, n = 7). After 24 h, ewes were weighed prior to plasma volume measurement procedures. Plasma volume was determined using the Evans blue dye method. Blood samples were taken at 0 (pre dye injection), 5, 10, 15, 20, 25, 30, 40, 50 and 60 min after dye injection. After the final blood collection, ewes were euthanized with an overdose of sodium pentabarbital and uterine weights were recorded. Uterine cross-sections were fixed in formalin for immunohistochemical localization of Ki67 (a marker of proliferating cells) followed by image generation of luminal epithelium and endometrial stroma (5 areas each/tissue section) and analysis to determine the proportion of proliferating cells. Plasma volume tended to be greater in E2 vs CON (2.75 ± 0.11 vs. 2.54 ± 0.12 L, P = 0.07) and uterine weights were greater in E2 vs CON (27.25 ± 2.35 vs. 17.35 ± 2.51 g, P < 0.01). Water intake after implant placement was similar in E2 and CON (3.85 vs. 4.87 ± 0.67 L; P = 0.28). Cell proliferation in the luminal epithelium was greater in E2 vs CON (6.55 vs. 1.2 ± 1.75%, P = 0.02) and stromal cells tended to be greater in E2 vs CON (0.59 vs 0.37 ± 0.06%, P = 0.07). Our results demonstrate that E2-treatment tends to increase plasma volume acutely and increases uterine cell proliferation in ewes.

Maternal periconceptual nutrition, early pregnancy, and developmental outcomes in beef cattle

The focus of this review is maternal nutrition during the periconceptual period and offspring developmental outcomes in beef cattle, with an emphasis on the first 50 d of gestation, which represents the embryonic period. Animal agriculture in general, and specifically the beef cattle industry, currently faces immense challenges. The world needs to significantly increase its output of animal food products by 2050 and beyond to meet the food security and agricultural sustainability needs of the rapidly growing human population. Consequently, efficient and sustainable approaches to livestock production are essential. Maternal nutritional status is a major factor that leads to developmental programming of offspring outcomes. Developmental programming refers to the influence of pre-and postnatal factors, such as inappropriate maternal nutrition, that affect growth and development and result in long-term consequences for health and productivity of the offspring. In this review, we discuss recent studies in which we and others have addressed the questions, "Is development programmed periconceptually?" and, if so, "Does it matter practically to the offspring in production settings?" The reviewed studies have demonstrated that the periconceptual period is important not only for pregnancy establishment but also may be a critical period during which fetal, placental, and potentially postnatal development and function are programmed. The evidence for fetal and placental programming during the periconceptual period is strong and implies that research efforts to mitigate the negative and foster the positive benefits of developmental programming need to include robust investigative efforts during the periconceptual period to better understand the implications for life-long health and productivity.

PSIV-16 Maternal Nutrient Restriction Followed by Re-alimentation Alters Distinct Metabolic Pathways in Sheep Offspring

To determine the effects of maternal nutrient restriction and re-alimentation on offspring metabolism, 48 pregnant ewes with singletons, were fed a control diet [100% National Research Council (NRC) requirements (CON)] starting at the beginning of gestation. On day 50 of gestation, ewes (n = 7) were euthanized and fetal liver, muscle, and blood samples were collected. The remaining animals were fed either CON or 60% NRC requirements (RES), a subset were euthanized at day 90 of gestation (n = 7/treatment), and fetal samples obtained. Remaining ewes were maintained on the current diet (CON-CON, n = 6; RES-RES, n = 7) or switched to alternative diet (CON-RES, RES-CON; n = 7/treatment). On day 130 of gestation, remaining ewes were euthanized, and fetal samples collected. Fetal liver, longissimus dorsi, and blood metabolites were analyzed using LC-MS/MS at Metabolon Inc. Pathway enrichment analysis was conducted using MetaboAnalyst 4.0. In liver, muscle, and blood, 64, 44, and 34 pathways were enriched between treatments at day 130 gestation and 10, 6, and 11 pathways were enriched at day 90 gestation, respectively. Arginine and proline metabolism; primary bile acid biosynthesis; and valine, leucine, and isoleucine biosynthesis were the most highly enriched pathways in RES compared with CON in liver, muscle, and blood, respectively. Additionally, the pentose phosphate pathway; valine, leucine, and isoleucine metabolism; and phenylalanine metabolism were the most highly enriched pathways in RES-CON compared with CON-CON in liver, muscle, and blood, respectively. In liver, ribulose 5-phosphate, xylulose 5-phosphate, and ribose 5-phosphate were decreased 1.82-, 1.54-, and 2.38-fold, respectively in RES-CON compared with CON-CON (P ≤ 0.05). Total triacylglycerols were increased 3.04-fold in muscle and decreased 1.57-fold in blood in RES-CON and RES-RES compared with CON-CON and CON-RES (P ≤ 0.05). Mid-gestational nutrient restriction and subsequent re-alimentation altered distinct metabolic amino acid, carbohydrate, and lipid pathways, potentially altering postnatal growth. Supported by USDA-AFRI grants 2016-67016-24884 and 2017-67016-26568.

PSIII-42 Genome-wide expression profile of trophoblastic cells during late pregnancy in ewes

During pregnancy, the placenta plays a pivotal role in fetal-maternal communication. Despite the known involvement of trophoblast mononuclear (MNC) and binuclear (BNC) cells in placentation and fetal development, the regulatory mechanisms underlying the gene expression in these cells and their role in pregnancy have not been fully elucidated. Thus, a genome-wide expression profile analysis of MNC and BNC from ovine placentomes on day 90 and 130 of pregnancy was performed to identify differentially expressed genes (DEG) and regulatory pathways. After tissue separation, enzymatic digestion, and elutriation, MNC and BNC were obtained, and the total RNA was isolated and sequenced (n = 2 ewes/day). Differential expression analysis was carried out with DESeq2 after library quality control and read mapping using FastQC and STAR, respectively. Among six pairwise contrasts possible, herein, we focused on the one between MNC and BNC on day 130. Accordingly, we identified 514 genes upregulated and 161 downregulated in BNC (adj.Pval &lt; 0.05). Interestingly, we found nine DE long intergenic noncoding RNAs (lincRNA). Although the function of lincRNAs remains under investigation, its transcription has been associated with gene expression regulation in utero. The DEGs functional over-representation analysis included Rap1 and PI3k-Akt signaling pathways as up-regulated in BNC (adj.Pval. &lt; 0.05). These pathways are activated by extracellular signals and are involved in cell proliferation and differentiation, morphogenesis, and energy metabolism. Furthermore, we identified PLA2G10 gene that codes a phospholipase protein involved in the production of prostaglandins, which have been associated with placental blood flow. These findings suggest an intricate and complex network underlying gene expression between cells and time points that are essential for the fetal-maternal placenta relationship. This project was supported by Agriculture and Food Research Initiative Competitive Grant n. 2016-67016-24884 from the USDA National Institute of Food and Agriculture.

Effects of fetal and maternal genotype on placentome morphology in sheep

Both maternal and fetal genotypes contribute to conceptus development. The objective was to determine how placentome number, size, and type and fetal weight was influenced after reciprocal embryo transfer in Columbia and Romanov sheep. Reciprocal embryo transfer was conducted between Columbia and Romanov ewes where a single embryo was transferred into Romanov and Columbia recipients [Romanov embryo in a Romanov uterus (RinR, n = 9); Romanov embryo in a Columbia uterus (RinC, n = 7); Columbia embryo in a Columbia uterus (CinC, n = 8); Columbia embryo in a Romanov uterus (CinR, n = 4)]. On day 130 of gestation, fetuses were weighed and placentomes were morphologically typed, weighed, and measured. Regardless of maternal genotype, Romanov fetuses were smaller (P < 0.05) compared to Columbia fetuses. Moreover, CinC fetuses were larger (P < 0.05) than CinR fetuses. There was a tendency (P = 0.12) for a fetal by maternal genotype interaction on total placentome weight, but main effects were significant for fetal genotype (P = 0.04) and maternal genotype (P < 0.01). The number of Type A placentomes was greater than any other types. Type A placentomes had a greater (P < 0.05) contribution to total placentome weight within the Romanov uterus, or when associated with a Romanov fetus, than within the Columbia breed, in which placentome type was evenly distributed. The hypothesis that the Romanov uterus would limit the growth of a Columbia conceptus is accepted; however, the Romanov conceptus did not experience augmented growth when transferred into a Columbia uterus as predicted.

Nutritionally induced tanycytic plasticity in the hypothalamus of adult ewes

The blood-brain barrier regulates the transport of molecules that convey global energetic status to the feeding circuitry within the hypothalamus. Capillaries within the median eminence (ME) and tight junctions between tanycytes lining the third ventricle (3V) are critical components of this barrier. Herein, we tested the hypothesis that altering the plane of nutrition results in the structural reorganization of tanycytes, tight junctions, and capillary structure within the medial basal hypothalamus. Proopiomelanocortin (POMC) neuronal content within the arcuate nucleus of the hypothalamus (ARC) was also assessed to test whether reduced nutritional status improved access of nutrients to the ARC, while decreasing the access of nutrients of overfed animals. Multiparous, nongestating ewes were stratified by weight and randomly assigned to dietary treatments offered for 75 d: 200% of dietary recommendations (overfed), 100% of dietary recommendations (control), or 60% of dietary recommendations (underfed). The number of POMC-expressing neurons within the ARC was increased (P ≤ 0.002) in underfed ewes. Overfeeding increased (P ≤ 0.01) tanycyte cellular process penetration and density compared with control and underfeeding as assessed using vimentin immunostaining. Immunostaining of tight junctions along the wall of the 3V did not differ (P = 0.32) between treatments. No differences were observed in capillary density (P = 0.21) or classification (P ≥ 0.47) within the ME. These results implicate that changes within the satiety center and morphology of tanycytes within the ARC occur as an adaptation to nutrient availability.

SUN-LB54 Nutritionally-Induced Alteration in KNDy Neuronal Expression in the Arcuate Nucleus of Ewes

Kisspeptin, neurokinin B, and dynorphin are imperative for GnRH/LH pulsatility and reproductive cyclicity. Neurons co-expressing these neuropeptides, KNDy neurons, within the arcuate nucleus of the hypothalamus (ARC) are positioned to integrate energy balance signals from neuronal and glial cells. Energy balance mediates neurokinin B expression in the ARC and LH pulse amplitude. Dynorphin mediates progesterone negative feedback on GnRH neurons. The hypothesis that the number of KNDy-expressing neurons in the ARC of ewes during the luteal phase of the estrous cycle is influenced by energy balance was tested using ovary-intact, mature ewes fed to lose, maintain, or gain body weight. Fluorescent multiplex immunohistochemistry was employed to identify and quantify neurons expressing a single neuropeptide and co-expressing kisspeptin, neurokinin B, and dynorphin in the ARC. Kaminski et al. (1) reported previously that concentrations of insulin and leptin differed between ewes fed to achieve different body weights and that ewes fed to gain body weight had increased concentrations of progesterone in the luteal phase of the estrous cycle. Moreover, tanycyte density and cellular penetration into the ARC are increased in ewes fed to gain body weight (2). Number of neurons in the ARC expressing kisspeptin (14.9 ± 2.7 neurons, 20.9 ± 3.6 neurons, and 51.5 ± 3.3 neurons in ewes fed to lose, maintain, and gain body weight, respectively), neurokinin B (21.5 ± 3.2 neurons, 31.3 ± 4.3 neurons, and 56.0 ± 3.9 neurons in ewes fed to lose, maintain, and gain body weight, respectively), and dynorphin (10.1 ± 2.4 neurons, 14.9 ± 3.2 neurons, and 33.1 ± 2.9 neurons in ewes fed to lose, maintain, and gain body weight, respectively) protein was increased (P &lt; 0.0001) in ewes fed to gain body weight. Number of KNDy neurons in the ARC expressing kisspeptin, neurokinin B, and dynorphin protein was decreased in ewes fed to lose body weight (1.0 ± 0.5 neurons; P = 0.01) and increased in ewes fed to gain body weight (6.7 ± 0.6 neurons; P = 0.0005) when compared to ewes fed to maintain body weight (3.3 ± 0.7 neurons). These findings suggest that expression of kisspeptin, neurokinin B, and dynorphin protein in the ARC during the luteal phase of the estrous cycle may be influenced by nutritionally-induced alterations in circulating concentrations of progesterone that drive changes in morphology and density of tanycytes. Moreover, these results demonstrate that changes in KNDy neurons within the ARC occur as an adaptation to energy balance, potentially regulated divergently by metabolic milieu.

References: (1) Kaminski et al., Theriogenology. 2015 83:808-16. (2) Prezotto et al., Domestic Animal Endocrinology. 2020 Accepted.

Follicle-stimulating hormone receptors expression in ovine corpora lutea during luteal phase: effect of nutritional plane and follicle-stimulating hormone treatment

Corpus luteum (CL), a transient endocrine gland critical for reproductive cyclicity and pregnancy maintenance, is controlled by numerous regulatory factors. Although LH is widely recognized as the major regulator, other factors may also affect luteal functions. It has been demonstrated that FSH receptors (FSHR) are expressed not only in ovarian follicles but also in other tissues within the reproductive tract, including the CL. To evaluate FSHR expression in nontreated (nonsuperovulated; experiment 1) or FSH-treated (superovulated; experiment 2) sheep fed a control (C; maintenance), excess (O; 2 × C), or restricted (U; 0.6 × C) diet, CL were collected at the early, mid and/or late luteal phases (n = 5-7 per group). Protein and messenger RNA (mRNA) expression of FSHR were detected in the CL from all groups using immunohistochemistry followed by image analysis and quantitative RT-PCR, respectively. Follicle-stimulating hormone receptor was immunolocalized to steroidogenic small and large and nonsteroidogenic luteal cells. In both experiments, FSHR protein expression was not affected by stage of luteal development or diet. In experiment 1, expression of mRNA for all FSHR variants was greater (P <0.02 to 0.0003) at the late phase than mid or early luteal phase, and in experiment 2, it was greater (P < 0.001) at the mid than early luteal phase. Plane of nutrition did not affect FSHR mRNA expression. Comparison of FSH-treated with nontreated ewes demonstrated that FSH increased FSHR protein expression by 1.5- to 2-fold (P < 0.0001) in all groups, and mRNA expression by 7- to 30-fold (P < 0.001) for (1) FSHR-1 in all groups except U at the early luteal phase, (2) FSHR-2 in C, O, and U at the mid-phase, but not early luteal phase, and (3) FSHR-3 in U at the mid-luteal phase. Our data demonstrate that (1) FSHRs are expressed in ovine CL at several stages of luteal development, (2) FSHR protein expression does not change during the luteal phase and is not affected by diet, (3) FSHR mRNA expression not only depends on the stage of the estrous cycle but also not affected by diet in nonsuperovulated or superovulated ewes, and (4) in vivo FSH treatment enhanced FSHR protein and/or mRNA expression in the CL depending on diet and phase of the estrous cycle. Presence of FSHR in the CL indicates a regulatory role of FSH in luteal function in sheep. As very little is known about the possible role of FSH and FSHR in luteal functions, further studies should be undertaken to elucidate the endocrine, molecular, and cellular mechanisms of FSH effects on the CL.

Nuclear and membrane progesterone receptors expression in placenta from early to late pregnancy in sheep: Effects of restricted nutrition and realimentation

Nutrient restriction and/or realimentation may affect several placental functions, such as expression of selected regulatory factors, blood flow and other processes in sheep and other species. To determine the effects of the plane of nutrition, nulliparous white face ewes (6-8 months) carrying singletons on day 50 of gestation were randomly assigned to two dietary treatments receiving 100% of National Research Council recommendations (control; C) or 60% of C (restricted; R). Two groups remained on C or R diets from day 50 until day 130. From day 90-130 another group of C fed ewes was switched to the R diet, and another group of R fed ewes was switched to the C diet. This resulted in 7 groups (n = 5-6 ewes/group): C (day 50, 90 and 130), R (day 90 and 130), CR (day 130) and RC (day 130). At these time points, placental tissues were collected for the evaluation of progesterone receptor (PGR) protein expression (whole tissue), and mRNA expression in maternal (caruncular, CAR) and fetal (cotyledon, COT) (separated tissues). Data were statistically analyzed using analysis of variance (SAS 9.4). Protein for PGRAB and PGRB isoforms was detected using immunohistochemistry in all placental tissues, but the pattern of expression differed depending on pregnancy stage and placental compartment (e.g., CAR vs COT). PGRAB protein expression, quantified using image analysis, was greater (P < 0.04) on day 50 than 90 or 130, and was not affected by plane of nutrition. In CAR and COT, PGRAB mRNA expression was greater (P < 0.05) on day 50 than 90 or 130. PGRB mRNA expression was greater (P < 0.03) in CAR on day 50 than 90 and 130, and was greatest (P < 0.02) in COT on day 50, less on day 130, and least on day 90. For the membrane progesterone receptors, PAQR7 (membrane PGR alpha) mRNA expression was greater (P < 0.05) on days 50 and 90 than 130 in CAR, and greater (P < 0.01) on days 50 than 90 and 130 in COT; PAQR8 (membrane PGR beta) was similar throughout pregnancy in CAR and COT, and PAQR5 (membrane PGR gamma) was greatest (P < 0.0001) on day 130 in COT, but similar throughout pregnancy in CAR. Plane of nutrition affected (P < 0.05) mRNA expression for all genes in CAR and COT throughout pregnancy. These data indicate that expression of PGR in ovine placenta is dependent on stage of pregnancy and plane of nutrition in sheep. The mechanisms of how diet and stage of pregnancy influences placental PGR expression and function remains to be elucidated.

PSII-35 Melatonin supplementation and restricted nutrition do not affect chorionic somatomammotropin (CSH) concentration in ovine placenta from mid- to late- gestation

Melatonin plays a role as a vasodilator. Vasoactive and angiogenic factors are expressed by placental binucleate cells (BNC) and produce chorionic somatomammotropin (CSH), known to impact fetal and placental growth. We hypothesized that melatonin supplementation and restricted nutrition from mid- to late-gestation would alter CSH concentration and some characteristics of BNC in placenta. At day 50 of gestation, ewes carrying singletons were randomly assigned to a 2 × 2 factorial design and were fed either an adequate (ADQ; 100% NRC; n = 15) or restricted (RES; 60% NRC; n = 15) diet supplemented with 0 (CON, n = 14) or 5 mg of melatonin (MEL; n = 16). Placentomes were collected on day 130 of gestation and preserved in formalin for histological analysis. Cotyledon (COT) were snap frozen for western immunoblotting analyses. Tissue sections were stained using biotinylated Dolichos Biflurus (DBA; a marker of fetal membrane) lectin and fluorescein labeled Texas red-avidin and fluorescein labeled Griffonia Simplifolica (BS) lectin (a marker of BNC). The number, area, and diameter of BNC in COT were determined by image analysis. For immunoblotting, protein was extracted from COT in SDS phosphate buffer, loaded equally, and separated on 12.5% polyacrylamide gels. Protein was transferred to PVDF membranes and incubated with rabbit anti-CSH. Bands were visualized and imaged. Data were analyzed using Proc Mixed procedure of SAS. Melatonin supplementation and restricted nutrition did not affect BNC number, area, or diameter, or CSH protein expression. While we reject our hypothesis that melatonin supplementation and nutrient restriction would alter the CSH concentration and BNC characteristics in COT, we continue to evaluate if the BNC produce angiogenic or vasoactive factors that may influence placental and mammary gland functions in sheep.

PSIV-8 Effects of restricted maternal nutrition and re-alimentation on fetal muscle development from mid to late gestation in sheep

Inadequate maternal nutrition during gestation negatively impacts offspring muscle development, which may be attenuated by re-alimentation. We hypothesized that restricted maternal nutrition would alter fetal muscle fiber cross-sectional area (CSA) and the percent of Pax7(+) progenitor cells. To test this, 48 primiparous ewes, pregnant with singletons, were fed 100% of NRC requirements (CON) between days 25 and 50 of gestation. At day 50 of gestation, seven ewes were euthanized for fetal sample collection. The remaining ewes were fed either CON or 60% NRC requirements (RES). At day 90 of gestation, seven ewes per diet were euthanized for fetal sample collection. The remaining ewes were maintained on their current diet (CON-CON, RES-RES) or switched to the alternate diet (CON-RES, RES-CON). At day 130 of gestation, all ewes (n = 6 or 7 ewes/diet) were euthanized, and fetal samples were collected. On days 90 and 130, fetal longissimus (LM) and triceps brachii (TB) were collected and immunostained for enumeration of Pax7(+) cells and muscle fiber CSA. The percent of Pax7(+) cells was determined by dividing the number of Pax7(+) cells by the total number of cells. At day 90 of gestation, the percent of Pax7(+) cells was less (P &lt; 0.01) in the TB of RES compared with CON. At day 130, fiber CSA was greater (P &lt; 0.04) in RES-CON compared with CON-CON, CON-RES, and RES-CON in the TB, and was greater (P &lt; 0.02) in RES-CON compared with RES-RES and CON-RES in the LM. An effect of maternal nutrition was not observed for the percent of Pax7(+) cells in the LM, or for CSA at day 90 in either muscle. Thus, restricted maternal nutrition during early to mid-gestation alters the percent of Pax7(+) cells at mid-gestation in a muscle specific manner. Re-alimentation during late gestation increased fiber CSA, demonstrating that re-alimentation alters fetal muscle development.

345 The effects of maternal nutrient restriction followed by re-alimentation on offspring growth and metabolism in sheep

The duration and timing of inadequate maternal nutrition can have detrimental effects on metabolism and organogenesis in the offspring. Re-alimentation, a common management practice that involves feeding full nutrient requirements following a period of nutrient restriction, may reduce the negative impacts of maternal nutrient restriction. To determine the effects of maternal nutrient restriction and re-alimentation on offspring growth,48 primiparous ewes, confirmed pregnant with singletons, were fed a control diet consisting of100% NRC requirements (CON) starting on day25 of gestation. On day50 of gestation, ewes (n = 7) were euthanized and fetal liver, muscle, and blood samples were collected. The remaining animals were fed either CON or60% NRC requirements (RES). On day90 of gestation, a portion of ewes were euthanized (n = 7 per treatment) and fetal samples and weights were collected. Remaining ewes were maintained on the current diet (CON-CON, n = 6; RES-RES, n = 7) or switched to the alternative diet (CON-RES, RES-CON; n = 7/treatment). On day130 of gestation, all remaining ewes were euthanized. All fetal BW, liver, longissimus muscle, semitendinosus, and triceps brachii weights were determined for each day of gestation. Fetal BW’s were not different between treatment groups (P = 0.29; P = 0.83). Fetal liver weights decreased12.89% in RES-RES compared with CON-CON at day130 (P = 0.049), but were not different at day90 (P = 0.69). There was a tendency for decreased semitendinosus weight in RES group compared with CON at day90 (P = 0.055). Liver lipid droplet accumulation was analyzed for day90 and130 using histochemistry and an effect of maternal nutrition was not observed (P = 0.562). In summary, maternal nutrient restriction reduces offspring muscle and liver growth. To gain insight into the effects of maternal nutrient restriction and re-alimentation on liver development and metabolism, analysis of liver morphology, gene expression, and global metabolomics are needed. Supported by USDA-AFRI grant2016-67016-24884

PSI-25 Effects of restricted maternal nutrition and realimentation during gestation on the fetal progenitor cell population in semitendinosus muscle of sheep

Satellite cells are muscle stem cells that contribute to postnatal growth. The satellite cell population is established during fetal muscle development, through the retention of Pax7-expressing myogenic progenitor cells. We hypothesized that realimentation during late gestation would ameliorate the negative effect of poor maternal nutrition during mid-gestation on the fetal myogenic progenitor cell population. To test this hypothesis, 47 ewes pregnant with singletons were fed a control diet of 100% of National Research Council (NRC) requirements (CON) starting at day 25 of gestation. At day 50 of gestation, six ewes were euthanized and the remainder were randomly assigned to one of two diets: CON or 60% of CON (RES). On day 90 of gestation, a subset of ewes were euthanized (n = 7 per treatment) and fetal semitendinosus samples were collected. The remaining ewes were maintained on the current diet (CON-CON, RES-RES) or switched to the alternative diet (CON-RES, RES-CON). On day 130 of gestation, all ewes were euthanized for fetal sample collection (n = 6–7 per treatment). Fetal semitendinosus was cryosectioned and immunostained for detection of Pax7(+) cells followed by image analysis. Data were analyzed using the MIXED procedure in SAS. Semitendinosus from RES lambs had a greater number of Pax7(+) cells but similar total cell numbers to CON offspring, resulting in a greater percentage of Pax7(+) cells at d90 of gestation (CON: 13.22 ± 0.74%; RES: 16.01 ± 0.74%, P = 0.01). At day 130, there was no difference in the percentage of Pax7(+) cells between dietary treatment groups (CON-CON: 7.88 ± 0.80%; CON-RES: 6.34 ± 0.74%; RES-RES: 7.82 ± 0.74%; RES-CON: 6.87 ± 0.74%; P &gt; 0.17). The percentage of Pax7(+) cells decreased from day 90 to day 130, regardless of dietary treatment (P &lt; 0.0001). In summary, restricted maternal nutrition may delay progenitor cell differentiation at mid-gestation.

Lipopolysaccharide disrupts gap junctional intercellular communication in an immortalized ovine luteal endothelial cell line

Gram-negative bacteria, in particular Escherichia coli with its cell wall lipopolysaccharide (LPS), often cause metritis and mastitis in domestic animals. Ovarian LPS accumulation may initiate local inflammatory reactions mediated through cell surface Toll-like receptors (TLRs). This may disrupt ovarian functionality leading to infertility. Possible adverse effects of LPS on luteal activity are not yet well explored. We hypothesized that LPS could lead to alterations in luteal vascular functionality. Therefore, we established an in vitro cell line model (OLENDO) by immortalizing microvascular endothelial cells isolated from ovine corpus luteum (CL) with a potent Simian Virus 40 T-antigen (SV40-Tag). OLENDO exhibit endothelial cell characteristics, like low-density lipoprotein (LDL) uptake, express BSL-I, and VEGFR2, as well as TLR2 and TLR4 receptors. LPS-treatment of OLENDO altered in vitro tube formation, had no effects on cell viability and decreased gap junctional intercellular communication (GJIC). LPS did not impair GJA1/Cx43 protein expression, but altered its cellular localization showing signs of internalization. Taken together, we demonstrated the mechanisms underlying LPS induced impairment of luteal GJIC and immune processes in a novel and well-characterized OLENDO cell line.

Effects of plane of nutrition and arginine on ovarian follicles in non-pregnant sheep: Cell proliferation, and expression of endothelial nitric oxide and its receptor

The aim of this study was to investigate the role of the nitric oxide (NO) system in ovarian function, by determining if arginine (Arg) supplementation impacts follicle number, cell proliferation, and expression of the NO system members in nutritionally compromised ewes. Ewes were randomly assigned into maintenance (C, 100% requirements), excess (O; 2xC), or restricted (U; 0.6xC) diets 8 weeks prior to Arg treatment. Ewes were individually fed twice daily with pelleted diets. Ewes from each nutritional group were randomly assigned to one of two treatments: saline or Arg, which was initiated on day 0 of the estrous cycle and administered 3 times per day. Ovaries were collected at the early-luteal, mid-luteal and late-luteal/follicular phases of the estrous cycle to determine 1) the number of surface follicles, 2) follicle cell proliferation marked by Ki67 protein expression, and 3) expression of endothelial nitric oxide (eNOS; NOS3) and soluble guanylyl cyclase beta (sGC; GUCY1B3) protein and mRNA in granulosa (G) and theca (T) layers using immunohistochemistry followed by image analysis and qPCR, respectively. During nutritional treatment, C maintained body weight, O gained 6±1.2 kg, and U lost 14±1.3 kg. Our data show that: 1) Ki67 was expressed in all ovarian compartments, eNOS protein was detected in blood vessels of T and stroma, and sGC protein was detected in T cells, and blood vessels of T layer and other ovarian compartments; 2) plane of nutrition affected the number of surface follicles, and thus folliculogenesis, cell proliferation in the T layer, eNOS and sGC protein expression in T, and NOS3 and GUCY1B3 mRNA expression in G; 3) Arg treatment affected cell proliferation in G and T, eNOS and sGC protein expression in T, mRNA expression of NOS3 in T in all groups, and GUCY1B3 in G depending on the stage of the estrous cycle; and 4) G and T cell proliferation, and expression of eNOS and sGC protein in T was affected by the stage of the estrous cycle. Our data demonstrated that plane of nutrition and Arg are involved in the regulation of follicular functions in non-pregnant sheep.

Placental development during early pregnancy in sheep: nuclear estrogen and progesterone receptor mRNA expression in the utero-placental compartments

Sex steroid hormones are major regulators of uterine and placental growth and functions, as well as many other biological processes. To examine the mRNA expression of nuclear estrogen (ESR1 and 2) and progesterone (PGRAB and B) receptors in different compartments of the uterus and placenta, tissues were collected in experiment 1 on days 16, 20, and 28 after natural mating (NAT) and on day 10 after estrus (nonpregnant controls [NP]); and in experiment 2 on day 22 of NAT, and pregnancies established after transfer of embryos generated through mating of FSH-treated ewes (NAT-ET), in vitro fertilization (IVF), or in vitro activation (parthenotes). In experiment 1, ESR1 expression in endometrial stroma (ES), endometrial glands (EGs), and myometrial blood vessels (MBVs), ESR2 in endometrial blood vessels (EBV), PGRAB in ES, and PGRB in ES, EG, and MBV was greater in pregnant than NP ewes depending on the day of pregnancy. The day of pregnancy affected the expression of ESR1 in MBV, ESR2 in EBV and MBV, and PGRAB in ES. In experiment 2, ESR1, PGRAB, and PGRB in EG, but not in other compartments, was greater in NAT-ET than NAT, and PGRB was greater for NAT-ET than IVF. These data demonstrate that ESR and PGR expression differ in pregnant versus NP ewes in selected compartments and was affected by pregnancy stage or embryo origin in selected utero-placental compartments. Thus, sex steroid hormone mRNA expression is differentially regulated in a spatiotemporal manner in the uterus and placenta and is affected by the application of assisted reproductive technology in sheep.

Angiopoietin expression in ovine corpora lutea during the luteal phase: Effects of nutrition, arginine and follicle stimulating hormone

The aim of this study was to evaluate angiopoietin (ANGPT) 1 and 2, and tyrosine-protein kinase receptor 2 (TIE2) expression in the corpora lutea (CL) of FSH-treated, or non-treated sheep administered arginine (Arg) or vehicle (saline, Sal), and fed a control (C), excess (O) or restricted (U) diet. Ewes from each dietary group were treated with Arg or Sal (experiment 1), and with FSH (experiment 2). Luteal tissues were collected at the early-, mid- and/or late-luteal phases of the estrous cycle. Protein and mRNA expression was determined using immunohistochemistry followed by image analysis, and quantitative RT-PCR, respectively. The results demonstrated that ANGPT1 and TIE2 proteins were localized to luteal capillaries and endothelial cells of larger blood vessels, and ANGPT2 was localized to tunica media of larger blood vessels. TIE2 protein was also present in luteal cells. In experiment 1, ANGPT1 protein expression was greater in O than C during early- and mid-luteal phases, and was greatest during late-luteal phase, less at the mid- and least at the early-luteal phase; 2) TIE2 protein expression was greatest at the mid-, less at the early- and least at the late-luteal phase; 3) ANGPT1 and 2 mRNA expression was greater at the mid- and late- than the early-luteal phase, and TIE2 mRNA expression was greatest at the late-, less at the mid- and least at the early-luteal phase. The ANGPT1/2 ratio was less at the early- than mid- or late-luteal phases. In experiment 2, ANGPT1 protein expression was greater in O during the mid-luteal phase than in other groups, and was greater at the mid- than early-luteal phase. TIE2 protein expression was highest at the mid-, less at the early- and least during the late-luteal phase. ANGPT1 and 2, and TIE2 mRNA expression was higher at the mid- than the early-luteal phase. During mid-luteal phase, ANGPT1 mRNA expression was greater in C than O and U, ANGPT2 was greatest in C, less in O and least in U, and TIE2 mRNA expression was greater in C than O and U. The ANGPT1/2 ratio was higher in U than in any other group. Comparison of FSH vs. Sal treatment effects (experiment 2 vs. experiment 1) demonstrated that FSH affected ANGPT1 and/or -2, and TIE2 protein and mRNA expression depending on luteal phase and/or diet. Thus, expression of ANGPTs and TIE2 in the CL changes during the luteal lifespan, indicating their involvement in luteal vascular formation, stabilization and degradation. Moreover, this study has demonstrated that plane of nutrition and/or FSH treatment affect the ANGPT system, and may alter luteal vascularity and luteal function in sheep.

Luteal ANGPT-TIE system during selected stages of pregnancy, and normal and antigestagen-induced luteolysis in the dog

Rapid establishment of a vascular network is essential for normal functionality of the corpus luteum (CL). The early luteal phase is associated with increased expression of the VEGF-system in canine CL. Acting in synchrony with angiopoietins (ANGPTs), VEGF-system plays major roles in stabilization of blood vessels. However, the expression of the ANPGT-system has not yet been investigated in the dog. Therefore, here, we investigated the luteal expression of ANGPT1, -2, and of their receptors TIE1 and -2, in pregnant dogs at selected time points during pregnancy and at normal and antigestagen-induced luteolysis. Additionally, luteal cells from early CL were incubated with PGE2 and its effects on the ANGPT-system were assessed. Whereas the luteal ANGPT1 was stable until mid-gestation, TIE1 was elevated post-implantation, their expression decreased towards prepartum luteolysis. The ANGPT2- and TIE2-mRNA did not vary during pregnancy. The ANGPT2/ANGPT1 ratio was elevated during prepartum luteolysis. PGE2 increased ANGPT2, but suppressed ANGPT1 levels. None of the ANGPT-system members was affected by antigestagen treatment in mid-pregnancy. Localization of ANGPT1 was predominantly found in the tunica intima and media of vessels and ANGPT2 stained strongly in luteal cells. Both ANGPTs were localized in macrophages. TIE1 stained in the vascular tunica media, in luteal cells and macrophages, whereas TIE2 was colocalized with ANGPT1 in vascular components. In conclusion, high expression of ANGPT1 during the increased presence of VEGFA in early canine CL implies its contribution to vascular network development. The upregulation of the ANGPT2/ANGPT1 ratio during prepartum luteolysis indicates involvement of the ANGPT-system in PGF2a-mediated vascular destabilization.

Follicle stimulating hormone receptor protein is expressed in ovine uterus during the estrous cycle and utero-placenta during early pregnancy: An immunohistochemical study

Follicle stimulating hormone (FSH) is a well characterized gonadotropin that controls primarily development and functions of ovarian follicles in mammalian species. FSH binds to a specific G protein-coupled receptor (FSHR) belonging to the glycoprotein hormone receptor family that plays an essential role in reproduction. Although the primary location of FSHR is in the gonads (mainly in ovarian follicles), FSHR protein and/or mRNA have also been detected in extragonadal female reproductive tissues including embryo, placenta, endometrium, cervix, ovarian cancer tissues, and/or endometriotic lesions in several species. To determine the pattern of FSHR expression in the uterus and placenta, uterine tissues were collected at the early, mid- and/or late luteal phases of the estrous cycle from non-treated or FSH-treated ewes, and utero-placental tissues were collected during early pregnancy followed by immunohistochemistry and image generation. FSHR was immunolocalized to several uterine and utero-placental compartments including luminal epithelium, endometrial glands and surrounding stroma, myometrium, and endothelium and vascular smooth muscle cells in endometrium, myometrium and mesometrium. Intensity of staining and distribution of FSHR in selected compartments differed and seems to depend on the stage of the estrous cycle or pregnancy, and FSH-treatment. These novel data demonstrate differential expression of FSHR protein indicating that FSH plays a specific role in regulation of uterine and utero-placenta functions in sheep.

Corpora lutea in superovulated ewes fed different planes of nutrition

The corpus luteum (CL) is an ovarian structure which is critical for the maintenance of reproductive cyclicity and pregnancy support. Diet and/or diet components may affect some luteal functions. FSH is widely used to induce multiple follicle development and superovulation. We hypothesized that FSH would affect luteal function in ewes fed different nutritional planes. Therefore, the aim of this study was to determine if FSH-treatment affects (1) ovulation rate; (2) CL weight; (3) cell proliferation; (4) vascularity; (5) expression of endothelial nitric oxide (eNOS) and soluble guanylate cyclase (sGC) proteins; and (6) luteal and serum progesterone (P4) concentration in control (C), overfed (O), and underfed (U) ewes at the early- and mid-luteal phases. In addition, data generated from this study were compared to data obtained from nonsuperovulated sheep and described by Bass et al. Ewes were categorized by weight and randomly assigned into nutrition groups: C (2.14 Mcal/kg; n = 11), O (2xC; n = 12), and U (0.6xC; n = 11). Nutritional treatment was initiated 60 d prior to day 0 of the estrous cycle. Ewes were injected with FSH on day 13-15 of the first estrous cycle, and blood samples and ovaries were collected at early- and mid-luteal phases of the second estrous cycle. The number of CL/ewe was determined, and CL was dissected and weighed. CL was fixed for evaluation of expression of Ki67 (a proliferating cell marker), CD31 (an endothelial cell marker), and eNOS and sGC proteins using immunohistochemistry and image analysis. From day 0 until tissue collection, C maintained, O gained, and U lost body weight. The CL number was greater (P < 0.03) in C and O than U. Weights of CL, cell proliferation, vascularity, and eNOS but not sGC expression were greater (P < 0.001), and serum, but not luteal tissue, P4 concentrations tended to be greater (P = 0.09) at the early- than mid-luteal phase. Comparisons of CL measurements demonstrated greater (P < 0.01) cell proliferation and serum P4 concentration, but less vascularity at the early and mid-luteal phases, and less CL weight at the mid-luteal phase in superovulated than nonsuperovulated ewes; however, concentration of P4 in luteal tissues was similar in both groups. Thus, in superovulated ewes, luteal cell proliferation and vascularity, expression of eNOS, and serum P4 concentration depend on the stage of luteal development, but not diet. Comparison to control ewes demonstrated several differences and some similarities in luteal functions after FSH-induced superovulation.

Expression of progesterone receptor protein in the ovine uterus during the estrous cycle: Effects of nutrition, arginine and FSH

To evaluate expression of progesterone receptor (PGR) AB in follicle stimulating hormone (FSH)-treated or non-treated sheep administered with arginine (Arg) or saline (Sal) fed a control (C), excess (O) or restricted (U) diet, uterine tissues were collected at the early, mid and/or late luteal phases. In exp. 1, ewes from each diet were randomly assigned to one of two treatments, Arg or Sal administration three times daily from day 0 of the first estrous cycle until uterine tissue collection. In exp. 2, ewes were injected twice daily with FSH on days 13-15 of the first estrous cycle. Uterine tissues were immunostained to detect PGR followed by image analysis. PGR were detected in luminal epithelium (LE), endometrial glands (EG), endometrial stroma (ES), myometrium (Myo), and endometrial and myometrial blood vessels. The percentage of PR-positive cells and/or intensity of staining were affected by phase of the estrous cycle, plane of nutrition, and/or FSH but not by Arg. In exp. 1, percentage of PGR-positive cells in LE and EG but not in ES and Myo was greater at the early and mid than late luteal phase, was not affected by plane of nutrition, and was similar in LE and EG. Intensity of staining was affected by phase of the estrous cycle and plane of nutrition in LE, EG and Myo, and was the greatest in LE, less in EG, and least in ES and Myo. In exp. 2, percentage of PGR-positive cells in LE, EG, ES and Myo was affected by phase of the estrous cycle, but not by plane of nutrition; was greater at the early than mid luteal phase; and was greatest in LE and EG, less in luminal (superficial) ES and Myo and least in deep ES. Intensity of staining was affected by phase of the estrous cycle and plane of nutrition in all compartments but ES, and was the greatest in LE and luminal EG, less in deep EG, and least in ES and Myo. Comparison of data for FSH (superovulated) and Sal-treated (non-superovulated) ewes demonstrated that FSH affected PR expression in all evaluated uterine compartments depending on plane of nutrition and phase of the estrous cycle. Thus, PGR are differentially distributed in uterine compartments, and PGR expression is affected by nutritional plane and FSH, but not Arg depending on phase of the estrous cycle. Such changes in dynamics of PGR expression indicate that diet plays a regulatory role and that FSH-treatment may alter uterine functions.

A Preliminary Evaluation of Ovine Bladder Mucosal Damage Associated With 2 Different Indwelling Urinary Catheters

OBJECTIVE

To determine whether a new catheter design with a low-profile, open-ended rounded rather than pointed Foley catheter tip can reduce mucosal damage to the bladder of ewes.

METHODS AND MATERIALS

Six ewes were randomly assigned to 1 of 2 indwelling urinary catheters-a 16 Fr Foley catheter or a 16 Fr open-tip CystoSure catheter. After 96 hours, all the animals were sacrificed and their bladder and urethra harvested for analysis.

RESULTS

Image analysis of the bladder surfaces demonstrated a significant decrease in the percentage of bladder area covered by ulceration and inflammation in sheep with CystoSure catheters compared with Foley catheters (P < .002) as well as a trend toward less edema (P = .17). Macro-morphologic evaluations were confirmed with immunohistochemical markers of cell proliferation and inflammation.

CONCLUSION

In this pilot study, we were able to demonstrate that a new catheter design with an open-ended rounded rather than pointed tip and a reduced balloon base-to-tip profile may reduce mucosal damage to the bladder of ewes. Based on the findings from this trial, we believe this new catheter design with its low-profile, rounded tip may reduce bladder mucosal injury, which is a risk factor for catheter-associated urinary tract infections.

The impact of diet and arginine supplementation on pancreatic mass, digestive enzyme activity, and insulin-containing cell cluster morphology during the estrous cycle in sheep

To determine the effect of feed intake and arginine treatment during different stages of the estrous cycle on pancreatic mass, digestive enzyme activity, and histological measurements, ewes (n = 120) were randomly allocated to 1 of 3 dietary groups; control (CON; 2.14-Mcal metabolizable energy/kg), underfed (UF; 0.6 × CON), or overfed (OF; 2 × CON) over 2 yr. Estrus was synchronized using a controlled internal drug release device for 14 d. At controlled internal drug release withdrawal, ewes from each dietary group were assigned to 1 of 2 treatments; Arg (L-Arg HCl, 155-μmol/kg BW) or Sal (approximately 10-mL saline). Treatments were administered 3 times daily via jugular catheter and continued until slaughter on d (day) 5 and 10 of the second estrus cycle (early luteal phase, n = 41 and mid-luteal phase, n = 39; yr 1) and d 15 of the first estrus cycle (late luteal phase, n = 40; yr 2). A blood sample collected from jugular catheters for serum insulin analysis before slaughter. The pancreas was then removed, trimmed of mesentery and fat, weighed, and a sample snap-frozen until enzyme analysis. Additional pancreatic samples were fixed in 10% formalin solution for histological examination of size and distribution of insulin-containing cell clusters. Data were analyzed as a completely randomized design with a factorial arrangement of treatments. Diet, treatment, and diet × treatment were blocked by yr and included in the model with initial BW used as a covariate. Day of the estrous cycle was initially included in the model but later removed as no effects (P > 0.10) were observed for any pancreatic variables tested. Overfed ewes had the greatest (P < 0.001) change in BW, final BW, change in BCS, and final BCS. A diet × treatment interaction was observed for change in BW and final BW (P ≤ 0.004). Overfed and CON had increased (P < 0.001) pancreas weight (g) compared with UF ewes. Protein concentration (g/pancreas) was the lowest (P < 0.001) in UF ewes, whereas protein content (mg/kg BW) was greater (P = 0.03) in UF than OF ewes. Activity of α-amylase (U/g, kU/pancreas, U/kg of BW, and U/g protein) and trypsin (U/pancreas) was greater (P ≤ 0.003) in OF than UF ewes. Serum insulin was the greatest (P < 0.001) in OF ewes. No effects were observed for pancreatic insulin-containing cell clusters. This study demonstrated that plane of nutrition affected several measurements of pancreatic function; however, the dosage of Arg used did not influence pancreatic function.

Luteal function during the estrous cycle in arginine-treated ewes fed different planes of nutrition

Functions of corpus luteum (CL) are influenced by numerous factors including hormones, growth and angiogenic factors, nutritional plane and dietary supplements such as arginine (Arg), a semi-essential amino acid and precursor for proteins, polyamines and nitric oxide (NO). The aim of this study was to determine if Arg supplementation to ewes fed different planes of nutrition influences: (1) progesterone (P4) concentrations in serum and luteal tissue, (2) luteal vascularity, cell proliferation, endothelial NO synthase (eNOS) and receptor (R) soluble guanylate cyclase β protein and mRNA expression and (3) luteal mRNA expression for selected angiogenic factors during the estrous cycle. Ewes (n = 111) were categorized by weight and randomly assigned to one of three nutritional planes: maintenance control (C), overfed (2× C) and underfed (0.6× C) beginning 60 days prior to onset of estrus. After estrus synchronization, ewes from each nutritional plane were assigned randomly to one of two treatments: Arg or saline. Serum and CL were collected at the early, mid and late luteal phases. The results demonstrated that: (1) nutritional plane affected ovulation rates, luteal vascularity, cell proliferation andNOS3,GUCY1B3, vascular endothelial growth factor (VEGF) andVEGFR2mRNA expression, (2) Arg affected luteal vascularity, cell proliferation andNOS3,GUCY1B3,VEGFandVEGFR2mRNA expression and (3) luteal vascularity, cell proliferation and the VEGF and NO systems depend on the stage of the estrous cycle. These data indicate that plane of nutrition and/or Arg supplementation can alter vascularization and expression of selected angiogenic factors in luteal tissue during the estrous cycle in sheep.

Gap junctional connexin messenger RNA expression in the ovine uterus and placenta: effects of estradiol-17β-treatment, early pregnancy stages, and embryo origin

Gap junctions play a major role in direct, contact-dependent cell-cell communication, and they have been implicated in the regulation of cellular metabolism and the coordination of cellular functions during growth and differentiation of organs and tissues. Gap junctional channels, composed of connexin (Cx) proteins, have been detected and shown to be influenced by hormones (eg, estrogen and progesterone) in uterine and placental tissues in several species. We hypothesized that (1) the messenger RNA (mRNA) for Cx26, Cx32, Cx37, and Cx43 is expressed in the uterus of ovariectomized sheep treated with estradiol-17β (E2) and in ovine placenta during early pregnancy, (2) E2-treatment of ovariectomized ewes would cause time-specific changes in Cx26, Cx32, Cx37, and Cx43 mRNA expression (experiment 1), and (3) expression of these 4 Cx would vary across the days of early pregnancy (experiment 2) and will be affected by embryo origin (ie, after application of assisted reproductive technologies [ARTs]; experiment 3). Thus, we collected uterine tissues at 0 to 24 h after E2 treatments (experiment 1), and placental tissues during days 14 to 30 of early pregnancy after natural (NAT) breeding (experiment 2) and on day 22 of early pregnancy established after transfer of embryos generated through natural breeding (NAT-ET), in vitro fertilization (IVF), or in vitro activation (IVA, parthenotes; experiment 3). In experiment 1, the expression of Cx26, Cx37, and Cx43 mRNA increased (P < 0.05) and Cx32 mRNA decreased (P < 0.06) in both caruncular and intercaruncular tissues after E2 treatment. In experiment 2, during early pregnancy, there were significant changes (P < 0.01) across days in the expression of Cx26, Cx37, and Cx43 mRNA in the maternal placenta, accompanied by changes (P < 0.001) in Cx37 and Cx43 mRNA in the fetal placenta. In experiment 3, in maternal placenta, Cx32 mRNA expression was decreased (P < 0.001) in NAT-ET, IVF, and IVA groups compared to the NAT group; but in fetal placenta, Cx32 mRNA expression was increased (P < 0.05) in NAT-ET, IVF and IVF groups, and Cx26 mRNA expression was increased (P < 0.05) in IVA compared to NAT group. These data suggest that Cx26, Cx32, Cx37, and Cx43 play specific roles in E2-regulated uterine function and in placental development during early gestation both after natural mating and with application of ART.

Lipid droplets in cultured luteal cells in non-pregnant sheep fed different planes of nutrition

Accumulation of lipid droplets (LD) in luteal cells likely is important for energy storage and steroidogenesis in the highly metabolically active corpus luteum (CL). The objective of this study was to determine the effect of plane of nutrition on progesterone (P4) secretion, and lipid droplet number and size in cultured ovine luteal cells. Ewes were randomly assigned to one of three nutritional groups: control (C; 100% NRC requirements, n=9), overfed (O; 2×C, n=12), or underfed (U; 0.6×C, n=10). Superovulation was induced by follicle stimulating hormone injections. At the early and mid-luteal phases of the estrous cycle, CL were dissected from ovaries, and luteal cells isolated enzymatically. Luteal cells were incubated overnight in medium containing serum in chamber slides. Media were then changed to serum-free and after 24h incubation, media were collected for P4 analysis, and cells were fixed in formalin and stained with BODIPY followed by DAPI staining. Z-stacks of optical sections of large and small luteal cells (LLC and SLC, respectively) were obtained using a laser-scanning microscope. Rendered 3D images of individual LLC and SLC were analyzed for cell volume, and total and individual LD volume, number and percentage of cellular volume occupied by LD by using Imaris software. Concentrations of P4 in serum and media were greater (P<0.05) at the mid than early-luteal phase, and were not affected by nutritional plane. LD total volume and number were greater (P<0.001) in LLC than SLC; however, mean volume of individual LD was greater (P<0.02) in SLC than LLC. In LLC, total LD volume was greater (P<0.02) in O than C and U ewes. In SLC, total LD volume and number was greater (P<0.003) at the mid than early-luteal phase, and percentage of cell volume occupied by LD was greater (P<0.002) in U than C and O ewes. These data demonstrate that both stage of luteal development and nutritional plane affect selected LD measurements and thus may affect luteal functions. Furthermore, these data confirm that LD dynamics differ among parenchymal steroidogenic luteal cell types.

Placental development during early pregnancy: Effects of embryo origin on expression of chemokine ligand twelve (CXCL12)

The aim was to localize chemokine ligand twelve (CXCL12) in sheep placental tissues during early gestation and after assisted reproductive technologies (ART). Uteri were collected from naturally (NAT) mated ewes and ewes receiving embryo transfer (ET), in vitro fertilization (IVF) or in vitro activation (IVA). CXCL12 was immunolocalized to endometrial stroma, glands, and trophoblast. Greater CXCL12 immunoreactivity was present in trophoblast on day 22 and 24 and in NAT ewes compared to IVF and IVA. Increased CXCL12 expression suggests CXCL12 promotes implantation and placentation. Decreased CXCL12 in IVF and IVA embryos, may compromise pregnancy establishment when utilizing ART methods.

Placental development during early pregnancy in sheep: estrogen and progesterone receptor messenger RNA expression in pregnancies derived from in vivo-produced and in vitro-produced embryos

Sex steroids are important regulators of angiogenesis and growth in reproductive tissues, including the placenta. In experiment (exp.) 1, to examine the expression of a suite of sex steroid receptors throughout early pregnancy, maternal (caruncular [CAR]) and fetal (fetal membranes [FM]) placental tissues were collected on days 14 to 30 after mating and on day 10 after estrus (nonpregnant controls). In exp. 2, to examine the hypothesis that assisted reproductive technology would affect the expression of the same suite of sex steroid receptors, pregnancies were achieved through natural mating (NAT) or transfer of embryos from natural mating (NAT-ET), in vitro fertilization (IVF), or in vitro activation (IVA), and CAR and FM were collected on day 22. In exp. 1, for CAR messenger RNA (mRNA) expression of estrogen receptors (ESR) 1 and 2, nuclear (n) progesterone receptors (PGR) and membrane (m) PGRα, β, and γ were affected (P < 0.02) by pregnancy stage, as were ESR1, nPGR, and mPGRα, β, and γ for FM (P < 0.03). In exp. 2, for CAR, mRNA expression of ESR1 and nPGR was decreased (P < 0.001) in NAT-ET, IVF, and IVA groups compared with NAT. For FM, mRNA expression of ESR1 tended to be greater (P = 0.10) in the IVA group compared with NAT and NAT-ET, and GPER1 was greater (P < 0.05) in NAT-ET and IVF compared with NAT. These data establish the normal pattern of sex steroid receptor mRNA expression in maternal and fetal placenta during early pregnancy in sheep, and in addition, suggest that altered expression of placental sex steroid receptors may be an early event leading to poor placental vascularization and growth after assisted reproductive technology.

Progesterone secretion by ovine granulosa cells: effects of nitric oxide and plane of nutrition

The aim was to evaluate the effects of nutritional plane on in vitro progesterone (P4) secretion by granulosa (G) cells cultured in the presence or absence of effectors of the nitric oxide (NO) system. Ewes were randomly assigned into three nutritional groups: control (C), overfed (O; 2 × C), or underfed (U; 0.6 × C). Follicular development was induced by FSH injections. On day 15 of the estrous cycle, G cells were isolated and cultured with or without DETA-NONOate (NO donor), L-NAME (NO synthase [S] inhibitor), Arg and (or) LH for 8 h. DETA-NONOate decreased basal and LH-stimulated P4 secretion, and L-NAME increased basal P4 secretion in all groups. In U, Arg decreased LH-stimulated P4 secretion. These data demonstrate that (i) plane of nutrition affects basal P4 secretion by G cells, (ii) the NO donor decreases, NOS inhibitor increases but Arg does not affect basal P4 secretion, and (iii) effects of Arg on LH-stimulated P4 secretion are affected by plane of nutrition in FSH-treated sheep. Thus, plane of nutrition affects G cell function, and the NO system is involved in the regulation of basal and LH-stimulated P4 secretion. The mechanism of the NO system effects on secretory activity of G cells remains to be elucidated.

Impact of maternal physical activity during gestation on porcine fetal, neonatal, and adolescent ovarian development

To determine how exercise from mid to late (days 40-104) gestation impacts offspring body, uterine and ovarian weight, and ovarian cell proliferation at three different developmental stages, Yorkshire gilts were either exercised by walking (EX) or not exercised (CON). In parity 1, ovaries and uteri were collected from the heaviest (H) and lightest (L) neonates and adolescent (6 mo) offspring. In parity 2, mothers were assigned the same treatment groups, and ovaries and uteri were collected from H and L fetuses on day 94 of gestation. Body weight was greater (P < 0.02) for H than L fetuses and neonates but not affected by EX treatment at any developmental stage. Ovarian weight in L but not H neonates was greater (P < 0.02) in EX than CON. Labeling index (LI; percentage of proliferating cells) was greater (P < 0.01) in cortex than medulla regions of fetal and neonatal ovaries. In fetal ovaries, EX enhanced LI (P < 0.01), and LI was greater (P < 0.01) in H compared with L offspring. In adolescent ovaries, LI was greatest (P < 0.01) in healthy antral and least in atretic antral follicles, and LI was greater (P < 0.01) in granulosa than theca cells of healthy antral follicles. Thus, exercise increased LI in fetal but not neonatal or adolescent ovaries. Although maternal exercise during gestation influences fetal and neonatal ovarian development, impacts on fertility remain unknown.

Placental development during early pregnancy in sheep: effects of embryo origin on vascularization

Utero-placental growth and vascular development are critical for pregnancy establishment that may be altered by various factors including assisted reproductive technologies (ART), nutrition, or others, leading to compromised pregnancy. We hypothesized that placental vascularization and expression of angiogenic factors are altered early in pregnancies after transfer of embryos created using selected ART methods. Pregnancies were achieved through natural mating (NAT), or transfer of embryos from NAT (NAT-ET), or IVF or in vitro activation (IVA). Placental tissues were collected on day 22 of pregnancy. In maternal caruncles (CAR), vascular cell proliferation was less (P<0.05) for IVA than other groups. Compared with NAT, density of blood vessels was less (P<0.05) for IVF and IVA in fetal membranes (FM) and for NAT-ET, IVF, and IVA in CAR. In FM, mRNA expression was decreased (P<0.01-0.08) in NAT-ET, IVF, and IVA compared with NAT for vascular endothelial growth factor (VEGF) and its receptor FLT1, placental growth factor (PGF), neuropilin 1 (NP1) and NP2, angiopoietin 1 (ANGPT1) and ANGPT2, endothelial nitric oxide synthase 3 (NOS3), hypoxia-inducible factor 1A (HIF1A), fibroblast growth factor 2 (FGF2), and its receptor FGFR2. In CAR, mRNA expression was decreased (P<0.01-0.05) in NAT-ET, IVF, and IVA compared with NAT for VEGF, FLT1, PGF, ANGPT1, and TEK. Decreased mRNA expression for 12 of 14 angiogenic factors across FM and CAR in NAT-ET, IVF, and IVA pregnancies was associated with reduced placental vascular development, which would lead to poor placental function and compromised fetal and placental growth and development.

Activation of the CXCL12/CXCR4 signaling axis may drive vascularization of the ovine placenta

Early pregnancy, when most embryonic losses occur, is a critical period in which vital placental vascularization is established. Vascular endothelial growth factor (VEGF) is a potent inducer of angiogenesis, and factors that regulate VEGF function, expression, or both may ultimately affect vascularization. Activation of the C-X-C chemokine receptor type 4 (CXCR4) by its cognate ligand, C-X-C chemokine ligand 12 (CXCL12), increases VEGF synthesis and secretion, which in turn stimulates CXCL12 and CXCR4 production and this synergistic regulation may influence placental vascularization. We hypothesized that expression of CXCL12, CXCR4, select angiogenic factors, and their receptors would increase in placental tissues during early pregnancy and that treatment of ovine trophectoderm cells with CXCL12 would increase production of angiogenic factors. To test this hypothesis, maternal caruncle (CAR) and fetal extraembryonic membrane (FM) tissues were collected on days 18, 20, 22, 25, 26, and 30 of pregnancy and on day 10 of the estrous cycle (control, NP) to determine relative mRNA or protein expression of CXCL12 and CXCR4 and selected angiogenic factors. In CAR, expression of mRNA for CXCR4 increased on day 18, 20, 22, and 25 and CXCL12 increased on day 18 and 20 compared with NP ewes. CXCL12 protein followed a similar pattern in CAR tissue, with greater levels on day 20 than in NP tissue. Greater levels of fibroblast growth factor 2 (FGF2) mRNA was observed in CAR on day 20 of gestation than on day 30. In FM, CXCL12, CXCR4, angiopoietin 1, VEGF, and VEGF receptor 1 were enhanced with advancing pregnancy, whereas FGF2 and kinase insert domain receptor (or VEGF receptor 2) peaked on day 25. An increase in protein levels occurred on day 25 compared with day 20 in FM for CXCL12 and CXCR4, as well as a similar tendency for FGF2 protein. Both CXCL12 and CXCR4 are specifically localized to trophoblast cells and to the uterine luminal and glandular epithelium. Treatment of ovine trophectoderm cells with CXCL12 increased mRNA expression for VEGF and FGF2. The relationship between VEGF, FGF2, and the CXCL12/CXCR4 signaling underscores the potential role for this chemokine axis in driving placentation.

Prion (PrPC) expression in ovine uteroplacental tissues increases after estrogen treatment of ovariectomized ewes and during early pregnancy

Scrapie in sheep is spread laterally by placental transmission of an infectious misfolded form (PrPSc) of a normal prion protein (PrPC) used as a template in PrPSc formation. We hypothesized that PrPC would be expressed in uterine and placental tissues and estradiol-17β (E2) would affect uterine PrPC expression. PrPC expression was evaluated in the uterus of long-term ovariectomized (OVX) ewes treated with an E2 implant for 2-24 h and in uteroplacental tissues from day 20 to day 30 of pregnancy. Expression of PrPC mRNA and PrPC protein increased in the uterus after E2 treatment of OVX ewes. In the maternal placenta, expression of PrPC mRNA and PrPC protein were unchanged, but in the fetal membranes (FM) PrPC mRNA and PrPC protein expression increased from day 20 to day 28. In the nonpregnant uterus, PrPC protein was immunolocalized at apical borders of the surface epithelium, in outer smooth muscle layers of large blood vessels, and in scattered stromal cells of the deep intercaruncular areas of the uterus. In the maternal placenta, PrPC protein was immunolocalized in the cytoplasm of flattened luminal epithelial cells apposed to the FM, whereas in the FM PrPC protein was in trophoblast cells and was also in several tissues of the developing embryo during early pregnancy. These data linking estrogen stimulation to increases in PrPC expression in uteroplacental tissues suggest that PrPC has a specific function during the estrous cycle and early pregnancy. Future studies should determine whether or not estrogen influences PrPC expression in other tissues, such as the nervous system and brain.

Vascular perfusion with fluorescent labeled lectin to study ovarian functions

The aim of this study was to optimize a method to visualize tissue vascularity by perfusing the local vascular bed with a fluorescently labeled lectin, combined with immunofluorescent labeling of selected vascular/tissue markers. Ovaries with the pedicle were obtained from adult non-pregnant ewes. Immediately after collection, the ovarian artery was perfused with phosphate buffered saline (PBS) to remove blood cells, followed by perfusion with PBS containing fluorescently labeled Griffonia (Bandeiraea) simplicifolia (BS1) lectin. Then, half of ovary was fixed in formalin and another half in Carnoy's fixative. BS1 was detected in blood vessels in ovaries fixed in formalin, but not in Carnoy's fixative. Formalin fixed tissue was used for immunofluorescence staining of two markers of tissue function and/or structure, Ki67 and smooth muscle cell actin (SMCA). Ki67 was detected in granulosa and theca cells, luteal and stromal tissue, and a portion of Ki67 staining was co-localized with blood vessels. SMCA was detected in pericytes within the capillary system, in blood vessels in all ovarian compartments, and in the stroma. Thus, blood vessel perfusion with fluorescently labeled lectin combined with immunohistochemistry, microscopy, and imaging techniques provide an excellent tool to study angiogenesis, vascular architecture, and organ structures and function in physiological and pathological conditions.

Overfeeding and underfeeding have detrimental effects on oocyte quality measured by in vitro fertilization and early embryonic development in sheep

To determine effects of maternal diet on in vitro fertilization (IVF) and early embryonic development, ewes (n = 48) were divided into control, overfed (ad libitum feeding), and underfed (60% of control) nutritional planes for 8 wk before oocyte collection. Follicular development was induced by twice-daily injections of FSH on days 13 and 14 of the estrous cycle, and ovaries and blood samples were collected on day 15 of the estrous cycle. During the 8-wk experiment, for control ewes BW and BCS did not change, but for overfed ewes mean (± SEM) BW and BCS increased (11.8 ± 1.1 kg and 2.0 ± 0.1, respectively) and for underfed ewes decreased (14.2 ± 0.9 kg and 0.7 ± 0.1, respectively). The number of follicles was determined; oocytes were collected and subjected to in vitro maturation and fertilization. After IVF, developing embryos were evaluated throughout the 8-d culture period. The proportion of cleaved oocytes after IVF and developing morula and blastocyst were less (P < 0.0001) in overfed and underfed ewes than in control ewes. However, number of visible follicles, total number of oocytes, number of healthy oocytes, and percentage of healthy oocytes were similar for control, overfed, and underfed ewes. Serum insulin concentration was greater (P < 0.05) in overfed ewes than in underfed ewes, estradiol 17-β (E(2)) concentration was greater (P < 0.05) in underfed ewes than in overfed ewes, but triiodothyronine (T(3)) and thyroxine (T(4)) concentrations were similar in all treatment groups. These data show that inadequate feeding has a negative effect on oocyte quality which results in lower oocyte cleavage after IVF and morula and blastocyst formation; overfeeding increased serum insulin and underfeeding increased serum E(2) but not T(3) or T(4). These data emphasize the importance of diet for reproductive and metabolic functions. Furthermore, the mechanisms through which enhanced or decreased energy in diet affect oocyte quality and serum insulin and E(2) concentrations remain to be elucidated.

Placental development during early pregnancy in sheep: effects of embryo origin on fetal and placental growth and global methylation

The origin of embryos including those created through assisted reproductive technologies might have profound effects on placental and fetal development, possibly leading to compromised pregnancies associated with poor placental development. To determine the effects of embryo origin on fetal size, and maternal and fetal placental cellular proliferation and global methylation, pregnancies were achieved through natural mating (NAT), or transfer of embryos generated through in vivo (NAT-ET), IVF, or in vitro activation (IVA). On Day 22 of pregnancy, fetuses were measured and placental tissues were collected to immunologically detect Ki67 (a marker of proliferating cells) and 5-methyl cytosine followed by image analysis, and determine mRNA expression for three DNA methyltransferases. Fetal length and labeling index (proportion of proliferating cells) in maternal caruncles (maternal placenta) and fetal membranes (fetal placenta) were less (P < 0.001) in NAT-ET, IVF, and IVA than in NAT. In fetal membranes, expression of 5-methyl cytosine was greater (P < 0.02) in IVF and IVA than in NAT. In maternal caruncles, mRNA expression for DNMT1 was greater (P < 0.01) in IVA compared with the other groups, but DNMT3A expression was less (P < 0.04) in NAT-ET and IVA than in NAT. In fetal membranes, expression of mRNA for DNMT3A was greater (P < 0.01) in IVA compared with the other groups, and was similar in NAT, NAT-ET, and IVF groups. Thus, embryo origin might have specific effects on growth and function of ovine uteroplacental and fetal tissues through regulation of tissue growth, DNA methylation, and likely other mechanisms. These data provide a foundation for determining expression of specific factors regulating placental and fetal tissue growth and function in normal and compromised pregnancies, including those achieved with assisted reproductive technologies.

Prognosis for clinical pregnancy and birth after transferring embryos derived from a cohort of incompletely mature oocytes at retrieval time

The purpose of this retrospective study was to establish a prognosis for implantation, pregnancy and live birth rates in stimulated IVF cycles after transferring embryos derived from: 1/ retrieved immature oocytes that matured overnight in vitro (late mature group: LM); 2/ retrieved immature oocytes that matured overnight in vitro and were added to the embryos derived from retrieved mature oocytes (mixed embryos group: MX); and 3/ retrieved mature oocytes (mature group: M). The obtained implantation, clinical pregnancy and live birth rates for the LM group were: 5.6%, 11.4%, 11.4%; for the MX group were: 4.2%, 14.6%, 11.6%; and for the M group were: 14.6%, 45.2% and 33.3%, respectively. These measurements were significantly lower p<0.05 for the LM and MX groups in comparison to the M group. The number of oocytes retrieved and the number of embryos transferred were the lowest (p<0.001-0.05) for the LM group. It is concluded, that the retrieved immature oocytes are able to mature during overnight culture in vitro, be fertilized and provide developmentally competent embryos with the prognosis of 11% for the successful delivery.

Expression of gap junctional connexin proteins in ovine fetal ovaries: effects of maternal diet

Gap junctions have been implicated in the regulation of cellular metabolism and the coordination of cellular functions during growth and differentiation of organs and tissues, and gap junctions play a major role in direct cell-cell communication. Gap junctional channels and connexin (Cx) proteins have been detected in adult ovaries in several species. Furthermore, it has been shown that several environmental factors, including maternal diet, may affect fetal organ growth and function. To determine whether maternal diet affects expression of Cx26, Cx32, Cx37, and Cx43 in fetal ovaries, sheep were fed a maintenance (M) diet with adequate (A) selenium (Se) or high (H) Se levels from 21 d before breeding to day 132 of pregnancy. From day 50 to 132 of pregnancy (tissue collection day), a portion of the ewes from the ASe and HSe groups was fed a restricted (R; 60% of M) diet. Sections of fetal ovaries were immunostained for the presence of Cxs followed by image analysis. All four Cxs were detected, but the distribution pattern differed. Cx26 was immunolocalized in the oocytes from primordial, primary, secondary, and antral follicles; in granulosa and theca layers of secondary and antral follicles; stroma; and blood vessels. Cx32 was in oocytes, granulosa, and theca cells in a portion of antral follicles; Cx37 was on the borders between oocyte and granulosa/cumulus cells of primordial to antral follicles and in endothelium; and Cx43 was on cellular borders in granulosa and theca layers and between oocyte and granulosa/cumulus cells of primordial to antral follicles. Maternal diet affected Cx26 and Cx43 expression, Cx26 in granulosa layer of antral follicles was decreased (P < 0.01) by HSe in the M and R diets, and Cx43 in granulosa layer of primary and granulosa and theca of antral follicles was increased (P < 0.05) by the M diet with HSe. Thus, Cxs may be differentially involved in regulation of fetal ovarian function in sheep. These data emphasize the importance of maternal diet in fetal growth and development.