Effect of Frozen Embryo Transfer and Progestin-primed Ovary Stimulation on IVF outcomes in women with high body mass index

Among women undergoing IVF, high BMI negatively affects pregnancy outcomes when using the conventional ovary stimulating protocols combined with fresh embryo transfer. Therefore, finding a proper treatment for these high BMI women is more important and urgent when obesity is prevalent. In our study, we reported a retrospective study of 4457 women who were divided into normal BMI group (18.5 kg/m²–24.9 kg/m²) and high BMI group (≥25 kg/m²) undergoing 4611 IVF treatment cycles with frozen embryo transfer (FET). We found the high BMI group originally had the poor oocytes performance, but after FET they got the similar pregnancy outcomes as the normal BMI group. Then under FET we analyzed the IVF outcomes of our new progestin-primed ovary stimulation (PPOS) protocol, indicating that the hMG + MPA (4 or 10 mg/d) groups had the obvious better pregnancy results than the conventional short group in the high BMI group, and binary logistic regression analysis showed the hMG + MPA (10 mg/d) group was associated with better pregnancy outcomes than the hMG + MPA (4 mg/d) group. These results indicate PPOS - hMG + MPA (10 mg/d) combined with FET might be a new potential treatment choice for the high BMI women undergoing IVF treatments.

Genome-scale identification of nucleosome organization by using 1000 porcine oocytes at different developmental stages

The nucleosome is the basic structural unit of chromosomes, and its occupancy and distribution in promoters are crucial for the regulation of gene expression. During the growth process of porcine oocytes, the "growing" oocytes (SF) have a much higher transcriptional activity than the "fully grown" oocytes (BF). However, the chromosome status of the two kinds of oocytes remains poorly understood. In this study, we profiled the nucleosome distributions of SF and BF with as few as 1000 oocytes. By comparing the altered regions, we found that SF tended toward nucleosome loss and more open chromosome architecture than BF did. BF had decreased nucleosome occupancy in the coding region and increased nucleosome occupancy in the promoter compared to SF. The nucleosome occupancy of SF was higher than that of BF in the GC-poor regions, but lower than that of BF in the GC-rich regions. The nucleosome distribution around the transcriptional start site (TSS) of all the genes of the two samples was basically the same, but the nucleosome occupancy around the TSS of SF was lower than that of BF. GO functional annotation of genes with different nucleosome occupancy in promoter showed the genes were mainly involved in cell, cellular process, and metabolic process biological process. The results of this study revealed the dynamic reorganization of porcine oocytes in different developmental stages and the critical role of nucleosome arrangement during the oocyte growth process.

ATRX is a novel progesterone-regulated protein and biomarker of low developmental potential in mammalian oocytes

A multi-species meta-analysis of published transcriptomic data from models of oocyte competence identified the chromatin remodelling factor ATRX as a putative biomarker of oocyte competence. The objective of the current study was to test the hypothesis that ATRX protein expression by cumulus-oocyte complexes (COCs) reflects their intrinsic quality and developmental potential. In excess of 10,000 bovine COCs were utilised to test our hypothesis. COCs were in vitro matured (IVM) under conditions associated with reduced developmental potential: IVM in the presence or absence of (1) progesterone synthesis inhibitor (Trilostane); (2) nuclear progesterone receptor inhibitor (Aglepristone) or (3) an inducer of DNA damage (Staurosporine). ATRX protein expression and localisation were determined using immunocytochemistry and Western blot analysis. A proportion of COCs matured in the presence or absence of Trilostane was in vitro fertilised and cultured, and subsequent embryo development characteristics were analysed. In addition, ATRX expression was investigated in 40 human germinal vesicle-stage COCs. Our results showed that ATRX is expressed in human and bovine germinal vesicle oocytes and cumulus cells. In bovine, expression decreases after IVM. However, this decline is not observed in COCs matured under sub-optimal conditions. Blastocyst development rate and cell number are decreased, whereas the incidence of abnormal metaphase phase spindle and chromosome alignment are increased, after IVM in the presence of Trilostane (P < 0.05). In conclusion, localisation of ATRX to the cumulus cell nuclei and oocyte chromatin, after IVM, is associated with poor oocyte quality and low developmental potential. Furthermore, ATRX is dynamically regulated in response to progesterone signalling.

Membrane progesterone receptors in reproduction and cancer

Progesterone is a sexual steroid hormone that has a critical role in reproductive processes in males and females of several species, including humans. Furthermore, progesterone has been associated with pathological diseases such as breast, gynecological and brain cancer, regulating cell proliferation, apoptosis, and metastasis. In the past, progesterone actions were thought to be only mediated by its intracellular receptor (PR). However, recent evidence has demonstrated that membrane progesterone receptors (mPRs) mediate most of the non-classical progesterone actions. The role of the different mPRs subtypes in progesterone effects in reproduction and cancer is an emerging and exciting research area. Here we review studies to date regarding mPRs role in reproduction and cancer and discuss their functions and clinical relevance, suggesting mPRs as putative pharmacological targets and disease markers in cancer and diseases associated with reproduction.

L-arginine affects the IVM of cattle cumulus-oocyte complexes

Nitric oxide (NO) is identified as a signaling molecule involved in many cellular or physiological functions, including meiotic maturation of cattle oocytes. This study aimed to evaluate the effect of supplementation of culture medium with the L-arginine (L-arg, NO synthesis precursor) in nuclear maturation of oocytes, concentrations of nitrate/nitrite, progesterone (P₄), and 17β-estradiol (E₂) in the culture medium; and the cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) intracellular concentrations in the cumulus-oocyte complexes (COCs) during the first hours of maturation in the presence of hemisections (HSs) of the follicular wall (control -ve). The addition of 5.0-mM L-arg increased (P < 0.05) the percentage of oocytes at the germinal vesicle breakdown stage after 7 hours of cultivation compared with control -ve. All concentrations of L-arg (2.5, 5.0, and 10.0 mM) increased the percentage of oocytes that reached the metaphase I (MI) at 15 hours (P < 0.05) but do not affect the progression from MI to metaphase II (P > 0.05) at 22 hours. All concentrations of L-arg tested increased (P < 0.05) the percentage of cumulus cells with plasma membrane integrity at 22 hours of cultivation. L-arginine did not change (P > 0.05) the nitrate/nitrite, P₄, and E₂ concentrations in relation to control -ve at any of the times tested. In immature COCs, immediately after being removed from the follicles (0 hours), the intracellular concentration of cGMP in the control -ve and treatment with 5-mM L-arg progressively decreased (P < 0.05) after the first hour of cultivation; however, COCs treated with 5.0-mM L-arg had higher concentrations of cGMP at 1 hour of cultivation (P < 0.05). The cAMP concentration of COCs supplemented or not with 5.0-mM L-arg progressively increased until 3 hours of cultivation and at, 6 hours, decreased (P < 0.05). The results show, in using this system, that (1) the mechanisms that give the oocyte the ability to restart the meiosis until MI after adding 5.0-mM L-arg do not involve changes in the concentration of nitrate/nitrite, P₄, and E₂ in the culture medium and (2) L-arg acts on a pathway that involves changing the cGMP concentration but does not involve changing cAMP concentration. More studies are needed to assess whether the observed effects of L-arg during IVM using this system are via NO or not and what the role is in increasing the viability of cumulus cells in the resumption and progression of meiosis until MI.

Progesterone influences cytoplasmic maturation in porcine oocytes developing in vitro

Progesterone (P4), an ovarian steroid hormone, is an important regulator of female reproduction. In this study, we explored the influence of progesterone on porcine oocyte nuclear maturation and cytoplasmic maturation and development in vitro. We found that the presence of P4 during oocyte maturation did not inhibit polar body extrusions but significantly increased glutathione and decreased reactive oxygen species (ROS) levels relative to that in control groups. The incidence of parthenogenetically activated oocytes that could develop to the blastocyst stage was higher (p < 0.05) when oocytes were exposed to P4 as compared to that in the controls. Cell numbers were increased in the P4-treated groups. Further, the P4-specific inhibitor mifepristone (RU486) prevented porcine oocyte maturation, as represented by the reduced incidence (p < 0.05) of oocyte first polar body extrusions. RU486 affected maturation promoting factor (MPF) activity and maternal mRNA polyadenylation status. In general, these data show that P4 influences the cytoplasmic maturation of porcine oocytes, at least partially, by decreasing their polyadenylation, thereby altering maternal gene expression.

The Utrogestan and hMG protocol in patients with polycystic ovarian syndrome undergoing controlled ovarian hyperstimulation during IVF/ICSI treatments

Poor oocyte quality is a main concern for decreased reproductive outcomes in women with polycystic ovarian syndrome (PCOS) during controlled ovarian hyperstimulation (COH). A primary way to improve oocyte quality is to optimize the COH protocol. It was demonstrated that the viable embryo rate per oocyte retrieved in the Utrogestan and hMG protocol, a novel regimen based on frozen-thawed embryo transfer (FET), is statistically higher than that in the short protocol. Thus, a retrospective study was conducted to evaluate the endocrine characteristics and clinical outcomes in PCOS patients subjected to the Utrogestan and hMG protocol compared with those subjected to the short protocol.One hundred twenty three PCOS patients enrolled in the study group and were simultaneously administered Utrogestan and human menopausal gonadotropin (hMG) from cycle day 3 until the trigger day. When the dominant follicles matured, gonadotropin-releasing hormone agonist (GnRH-a) 0.1 mg was used as the trigger. A short protocol was applied in the control group including 77 PCOS women. Viable embryos were cryopreserved for later transfer in both groups. The primary outcome was the viable embryo rate per oocyte retrieved. The secondary outcomes included the number of oocytes retrieved, fertilization rate, and clinical pregnancy outcomes from FET cycles.The pituitary luteinizing hormone (LH) level was suppressed in most patients; however, the LH level in 13 women, whose basic LH level was more than 10 IU/L, surpassed 10 IU/L on menstruation cycle day (MC)9-11 and decreased subsequently. No significant between-group differences were observed in the number of oocytes retrieved (13.27 ± 7.46 vs 13.1 ± 7.98), number of viable embryos (5.57 ± 3.27 vs 5 ± 2.79), mature oocyte rate (90.14 ± 11.81% vs 93.02 ± 8.95%), and cleavage rate (97.69 ± 6.22% vs 95.89 ± 9.57%). The fertilization rate (76.11 ± 19.04% vs 69.34 ± 21.81%; P < 0.05), viable embryo rate per oocyte retrieved (39.85% vs 34.68%; P < 0.05), biochemical pregnancy rate (71.72% vs 56.67%; P < 0.05), clinical pregnancy rate (64.65% vs 51.65%; P < 0.05), and implantation rate (46.46% vs 31.35%; P < 0.05) in the study group were significant higher than those in the control group.This study shows that the Utrogestan and hMG protocol was feasible to improve the oocyte quality, possibly providing a new choice for PCOS patients undergoing IVF/ICSI treatments in combination with embryo cryopreservation.

PGRMC1 participates in late events of bovine granulosa cells mitosis and oocyte meiosis

Progesterone Receptor Membrane Component 1 (PGRMC1) is expressed in both oocyte and ovarian somatic cells, where it is found in multiple cellular sub-compartments including the mitotic spindle apparatus. PGRMC1 localization in the maturing bovine oocytes mirrors its localization in mitotic cells, suggesting a possible common action in mitosis and meiosis. To test the hypothesis that altering PGRMC1 activity leads to similar defects in mitosis and meiosis, PGRMC1 function was perturbed in cultured bovine granulosa cells (bGC) and maturing oocytes and the effect on mitotic and meiotic progression assessed. RNA interference-mediated PGRMC1 silencing in bGC significantly reduced cell proliferation, with a concomitant increase in the percentage of cells arrested at G2/M phase, which is consistent with an arrested or prolonged M-phase. This observation was confirmed by time-lapse imaging that revealed defects in late karyokinesis. In agreement with a role during late mitotic events, a direct interaction between PGRMC1 and Aurora Kinase B (AURKB) was observed in the central spindle at of dividing cells. Similarly, treatment with the PGRMC1 inhibitor AG205 or PGRMC1 silencing in the oocyte impaired completion of meiosis I. Specifically the ability of the oocyte to extrude the first polar body was significantly impaired while meiotic figures aberration and chromatin scattering within the ooplasm increased. Finally, analysis of PGRMC1 and AURKB localization in AG205-treated oocytes confirmed an altered localization of both proteins when meiotic errors occur. The present findings demonstrate that PGRMC1 participates in late events of both mammalian mitosis and oocyte meiosis, consistent with PGRMC1's localization at the mid-zone and mid-body of the mitotic and meiotic spindle.

Mechanisms underlying reduced fertility in anovular dairy cows

Resumption of ovulation after parturition is a coordinated process that involves recoupling of the GH/insulin-like growth factor 1 axis in the liver, increase in follicular development and steroidogenesis, and removal of negative feedback from estradiol in the hypothalamus. Infectious diseases and metabolic disorders associated with extensive negative energy balance during early lactation disrupt this pathway and delay first ovulation postpartum. Extended periods of anovulation postpartum exert long-lasting effects on fertility in dairy cows including the lack of spontaneous estrus, reduced pregnancy per artificial insemination (P/AI), and increased risk of pregnancy loss. Concentrations of progesterone in anovular cows subjected to synchronized programs for AI are insufficient to optimize follicular maturation, oocyte competence, and subsequent fertility to AI. Ovulation of first wave follicles, which develop under low concentrations of progesterone, reduces embryo quality in the first week after fertilization and P/AI in dairy cows. Although the specific mechanisms by which anovulation and low concentrations of progesterone impair oocyte quality have not been defined, studies with persistent follicles support the involvement of premature resumption of meiosis and degradation of maternal RNA. Suboptimal concentrations of progesterone before ovulation also increase the synthesis of PGF2α in response to oxytocin during the subsequent estrous cycle, which explains the greater incidence of short luteal phases after the first AI postpartum in anovular cows compared with estrous cyclic herd mates. It is suggested that increased spontaneous luteolysis early in the estrous cycle is one of the mechanisms that contributes to early embryonic losses in anovular cows. Anovulation also leads to major shifts in gene expression in elongated conceptuses during preimplantation stages of pregnancy. Transcripts involved with control of energy metabolism and DNA repair were downregulated, whereas genes linked to apoptosis and autophagy were upregulated in Day 15 conceptuses collected from anovular cows compared with estrous cyclic counterparts. Similar changes in conceptus transcriptome were not observed in estrous cyclic cows induced to ovulate follicles that grew under low and high concentrations of progesterone, indicating an effect of anovulation on embryonic development that is not mediated solely by progesterone concentrations before ovulation. Finally, risk factors for anovulation have direct effects on embryo development and uterine receptivity to pregnancy that complement those determined by insufficient concentrations of progesterone during follicular growth. One approach to minimize the impact of anovulation on fertility is supplementation with progesterone during recruitment, selection and final stages of development of the preovulatory follicle. It is suggested that a minimum of 2.0 ng/mL of progesterone is needed during growth of the preovulatory follicle to achieve P/AI similar to that of cows growing the preovulatory follicle during diestrus.

Does metformin improve in vitro maturation and ultrastructure of oocytes retrieved from estradiol valerate polycystic ovary syndrome-induced rats

Background

Metformin decreases polycystic ovary syndrome (PCOS) symptoms, induces ovulation, and may improve developmental competence of in vitro oocyte maturation. This study was designed to define the effects of metformin on the characteristics of in vitro oocyte maturation in estradiol valerate (EV) PCOS-induced rats.

Methods

Forty-five adult female Sprague–Dawley rats were randomly divided into control; sham and PCOS-induced (treated by a single dose of estradiol valerate, 4 mg/rat, IM) groups. The body weight was measured weekly for 12 weeks. At the end of week 12, the serum levels of testosterone, estrogen, progesterone, LH, and FSH and blood glucose of all the rats were measured. About 380 cumulus oocyte complexes (control, 125; sham, 122; PCOS-induced rats, 133) were incubated in Ham’s F10 in the absence and/or presence of metformin (M 5⁻¹⁰) for 12, 24, 36, and 48 h. The cumulus cells expansion and nuclear and cytoplasmic maturation of the oocytes was evaluated using 1 % aceto-orcein staining, and transmission electron microscopy (TEM).

Results

No significant differences were observed in the body weight of the rats. The serum level of testosterone was reduced, and progesterone and LH were significantly increased in the PCOS-induced rats (p < 0.05). However, no significant differences were observed in the serum levels of estrogen and FSH among the groups. Blood glucose level was higher in the PCOS-induced rats than control, (p < 0.01). The expansion of cumulus cells was observed in the metformin-treated oocytes. The oocytes retrieved from PCOS-induced rats show a stage of meiotic division (GVBD, MI, A-T, and MII) in 57.12 % of metformin-untreated and fairly significantly increased to 64.28 % in metformin-treated oocytes, (p < 0.05), but no differences were observed in the MII stage within groups. The redistribution of some cytoplasmic organelles throughout the ooplasm, particularly the peripheral cortical granules, was defined in the metformin-treated oocytes.

Conclusions

Single dose of EV can creates a reversible PCO adult rat model. Metformin enhances the COCs to initiate meiotic resumption at the first 6 h of IVM. In our study the metformin inability to show all aspects of in vitro oocyte maturation and may be resulted from deficiency of EV to induce PCOS.

Form of supplemental selenium fed to cycling cows affects systemic concentrations of progesterone but not those of estradiol

In areas where soils are deficient in selenium (Se), dietary supplementation of this trace mineral directly to cattle is recommended. Selenium status affects fertility, and the form of Se supplemented to cows affects tissue-specific gene expression profiles. The objective of this study was to determine whether the form of Se consumed by cows would affect follicular growth and the production of steroids. Thirty-three Angus-cross cows that had ad libitum access of a mineral mix containing 35 ppm of Se in free-choice vitamin-mineral mixes as either inorganic (ISe), organic (OSe), or a 50/50 mix of ISe and OSe (MIX) for 180 days were used. After 170 days of supplementation, all cows were injected with 25-mg PGF2α to induce regression of the CL and then monitored for behavioral estrus (Day 0). From Day 4 to Day 8 after estrus, follicular growth was determined by transrectal ultrasonography. On Day 6, cows were injected with PGF2α (20 then 15 mg, 8-12 hours apart) to induce regression of the developing CL and differentiation of the dominant follicle of the first follicular wave into a preovulatory follicle. On Day 8, 36 hours after PGF2α (20 mg), the contents of the preovulatory follicle were aspirated by ultrasound-guided follicular puncture. Blood collected on Days 6 and 8 and follicular fluid collected on Day 8 was analyzed for concentrations of progesterone and estradiol. Form of Se supplemented to cows affected (P = 0.04) the systemic concentration of progesterone on Day 6, but not on Day 8. Form of Se did not affect the systemic concentration of estradiol on Day 6 or Day 8. Form of Se tended to affect (P = 0.07) the concentration of progesterone, but not that of estradiol, in the follicular fluid. Form of Se did not affect diameter of the dominant ovarian follicle on Days 4 to 6, but tended to affect (P = 0.08) the diameter of the preovulatory follicle on Day 8. Our results suggest that form of Se fed to cows affects the production of progesterone but not that of estradiol. Further investigation of organic Se-induced increases in progesterone and potentially the effects of increased progesterone on the establishment of pregnancy, especially in cows of lower fertility, is warranted.

Progesterone plays a critical role in canine oocyte maturation and fertilization

Canine oocyte maturation and fertilization take place within the oviducts under increasing plasma levels of progesterone (P4). In order to investigate the role of P4 in these processes, 51 beagle bitches were treated with the P4 receptor antagonist aglepristone at the end of proestrus and 32 females were kept untreated. Fifteen treated and 13 control bitches were inseminated at Days +1 and +2 after ovulation (Day 0). Stages of oocyte maturation and embryo development were determined after ovariectomy at different time points after ovulation. Aglepristone did not prevent ovulation but delayed the resumption of oocyte meiosis and inhibited its progression: first metaphase I (MI) stage was observed at 173 h postovulation and 39% of oocytes reached MII as late as 335 h postovulation in treated females whereas first MI occurred at 76 h and 100% of oocytes were in MII at 109 h postovulation in controls. Aglepristone extended the stay of morphologically normal oocytes within the oviducts: first signs of oocyte degeneration were observed at 335 h in treated versus 100- to 110-h postovulation in control bitches. In inseminated females, aglepristone prevented sperm progression toward the oviducts and fertilization, although motile spermatozoa were observed in the uterine tip flush and within the cranial uterine glands. A proteomic analysis of the tubal fluid from treated and control noninseminated bitches at Day +4 found evidence of 79 differential proteins potentially involved in the oocyte phenotype. In conclusion, P4 plays key roles in postovulatory canine oocyte maturation, aging, and in fertilization.

Cumulus cell gene expression associated with pre-ovulatory acquisition of developmental competence in bovine oocytes

The final days before ovulation impact significantly on follicular function and oocyte quality. This study investigated the cumulus cell (CC) transcriptomic changes during the oocyte developmental competence acquisition period. Six dairy cows were used for 24 oocyte collections and received FSH twice daily over 3 days, followed by FSH withdrawal for 20, 44, 68 and 92 h in four different oestrous cycles for each of the six cows. Half of the cumulus-oocyte complexes were subjected to in vitro maturation, fertilisation and culture to assess blastocyst rate. The other half of the CC underwent microarray analysis (n=3 cows, 12 oocyte collections) and qRT-PCR (n=3 other cows, 12 oocyte collections). According to blastocyst rates, 20 h of FSH withdrawal led to under-differentiated follicles (49%), 44 and 68 h to the most competent follicles (71% and 61%) and 92 h to over-differentiated ones (51%). Ten genes, from the gene lists corresponding to the three different follicular states, were subjected to qRT-PCR. Interestingly, CYP11A1 and NSDHL gene expression profiles reflected the blastocyst rate. However most genes were associated with the over-differentiated status: GATM, MAN1A1, VNN1 and NRP1. The early period of FSH withdrawal has a minimal effect on cumulus gene expression, whereas the longest period has a very significant one and indicates the beginning of the atresia process.

Expression and cellular distribution of estrogen and progesterone receptors and the real-time proliferation of porcine cumulus cells

Although the expression of estrogen and progesterone receptors within porcine ovary and cumulus–oocyte complexes (COCs) is well recognized, still little information is known regarding expression of the progesterone receptor (PGR), PGR membrane component 1 (PGRMC1) and of estrogen-related receptors (ERRγ and ERRβ/γ) in separated cumulus cells in relation to real-time proliferation. In this study, a model of oocytes-separated cumulus cells was used to analyze the cell proliferation index and the expression PGR, PGRMC1 and of ERRγ and ERRβ/γ during 96-h cultivation in vitro using real-time quantitative PCR (qRT-PCR) and confocal microscopic observation. We found that PGR protein expression was increased at 0 h, compared with PGR protein expression after 96 h of culture (P < 0.001). The expression of PGRMC1, ERRγ and ERRβ/γ was unchanged. After using qRT-PCR we did not found statistical differences in expression of PGR, PGRMC1, ERRγ and ERRβ/γ during 96 h of cumulus cells in vitro culture (IVC). We supposed that the differential expression of the PGR protein at 0 h and after 96 h is related to a time-dependent down-regulation, which may activate a negative feedback. The distribution of PGR, PGRMC1 proteins may be linked with the translocation of receptors to the cytoplasm after the membrane binding of respective agonists and intra-cytoplasmic signal transduction. Furthermore, cumulus cells analyzed at 0 h were characterized by decreased proliferation index, whereas those after 96 h of culture revealed a significant increase of proliferation index, which may be associated with differentiation/luteinization of these cells during real-time proliferation.

Effects of RU486 and indomethacin on meiotic maturation, formation of extracellular matrix, and progesterone production by porcine oocyte-cumulus complexes

This study was designed to determine whether inhibition of either cyclooxygenase-2 (COX-2) by indomethacin or progesterone receptor (PR) by PR antagonist, RU486, affects oocyte maturation, progesterone production, and covalent binding between hyaluronan (HA) and heavy chains of inter-α trypsin inhibitor, as well as expression of cumulus expansion-associated proteins (HA-binding protein, tumor necrosis factor α-induced protein 6, pentraxin 3) in oocyte-cumulus complexes (OCCs). The experiments were based on freshly isolated porcine OCC cultures in which the consequences of PR and COX-2 inhibition on the final processes of oocyte maturation were determined. Granulosa cells (GCs) and OCCs were cultured in medium supplemented with FSH/LH (both 100 ng/mL) in the presence/absence of RU486 or indomethacin. Western blot analysis, (3)H-glucosamine hydrochloride assay, immunofluorescence, and radioimmunoassay were performed. Only treatment with RU486 (25 μM) caused a decrease in the number of oocytes that reached germinal vesicle breakdown and metaphase II stage compared with indomethacin (100 μM) or FSH/LH treatment alone after 44 h. All treated OCCs synthesized an almost equal amount of HA. Heavy chains (of inter-α trypsin inhibitor)-HA covalent complexes were formed during in vitro FSH/LH-stimulated expansion in RU486- or indomethacin-treated OCCs. Follicle-stimulating hormone/LH-induced progesterone production by OCCs was increased in the presence of RU486 after 44 h. In contrast, a decrease of FSH/LH-stimulated progesterone production by GCs was detected in the presence of either RU486 or indomethacin after 72 h. We suggest that the PR-dependent pathway may be involved in the regulation of oocyte maturation. Both PR and COX-2 regulate FSH/LH-stimulated progesterone production by OCCs and GCs.

The effect of hormonal estrus induction on maternal effect and apoptosis-related genes expression in porcine cumulus-oocyte complexes

BACKGROUND

The effect of hormonal estrus induction on maternal effect (MATER - maternal antigen that embryo requires, ZAR-1 - zygote arrest 1, and BMP15 - bone morphogenetic protein 15) and apoptosis-related genes expression (BCL-2 and BAX) in porcine cumulus-oocyte complexes (COCs) and selected follicular parameters was investigated in this study.

METHODS

Gilts were divided into three groups: (I) with natural estrus; (II) stimulated with PMSG/hCG; and (III) with PMSG/hCG + PGF2alpha. Analysis of maternal effect and apoptosis-related transcripts expression in COCs, and progesterone synthesis pathway genes expression (P450scc and 3betaHSD) in granulosa cells was performed by qPCR. BMP15 protein expression in follicular fluid (FF) was analyzed by western blot. Oocyte nuclear maturation was assessed by aceto-orcein staining. Progesterone (P4) and estradiol (E2) concentrations in FF and serum were measured by ELISA. Data were analyzed with the one-way ANOVA and Bonferroni post-test or Kruskal-Wallis test and Dunns post-test.

RESULTS

The highest expression of MATER, ZAR-1, and BMP15 genes was found in COCs recovered from gilts treated with PMSG/hCG when compared to PMSG/hCG + PGF2alpha-stimulated or non-stimulated gilts. Hormonal treatment did not affect the BMP15 protein expression in FF, but increased the expression of genes participating in P4 synthesis in granulosa cells. The higher percentage of immature oocytes was found in PMSG/hCG-treated when compared to the non-stimulated gilts. The expression of BCL-2 and BAX mRNA, and BCL-2/BAX mRNA ratio was significantly higher in COCs derived from PMSG/hCG-treated when compared to PMSG/hCG + PGF2alpha-treated or non-stimulated subjects. The level of P4 in serum was similar in animals from all experimental groups, while its concentration in FF was greater in gilts subjected to PMSG/hCG treatment than in PMSG/hCG + PGF2alpha-stimulated and non-stimulated gilts. The concentration of E2 did not differ in the serum or FF between the control group and the hormonally stimulated groups.

CONCLUSIONS

Hormonal induction of estrus affected maternal effect gene transcripts levels in COCs and and oocyte nuclear maturation. The inclusion of PGF2alpha into the stimulation protocol enabled maintaining of physiological concentration of P4 in FF. Additionally, both hormonal treatments seem to be beneficial for apoptosis prevention through increasing BCL-2/BAX transcript ratio.

Expression of nuclear and membrane progesterone receptors in the canine oviduct during the periovulatory period

Important reproductive events take place in the canine oviduct in the presence of increasing concentrations of progesterone (P4). To investigate the potential effects of P4 on the canine oviduct, the expression of nuclear (PR) and membrane (PGRMC1 and 2, mPRα, β and γ) P4 receptors was studied by quantitative RT-PCR and immunohistochemistry. Oviducts were collected from Beagle bitches after the onset of pro-oestrus and before the LH peak (Pre-LH), after the LH peak and before ovulation (Pre-ov) and on Days 1, 4 and 7 post-ovulation (n=6 bitches/stage). PR mRNA concentrations decreased from Pre-LH to Day 7 in the ampulla and isthmus, whereas both PGRMC1 and 2 mRNA levels increased over the same period. The main change in mPR expression was an increase in mPRβ and γ mRNAs at Day 7 in the isthmus. Furthermore, PR proteins were expressed in the nuclei of luminal epithelial, stromal and muscular cells, whereas the expression of PGRMCs and mPRs was primarily cytoplasmic and localised in the luminal epithelium. The immunostaining for PR decreased at Day 4 in the stroma and muscle, whereas it remained strong in the epithelium from Pre-LH to Day 7. PGRMC1 staining was strong at Days 4 and 7 whereas PGRMC2 was highly expressed from Pre-ov to Day 7. The most intense immunostaining signals for all three mPRs were observed at Day 7. Our results strongly support the hypothesis that P4 is an important regulator of oviductal functions in the bitch through complementary classical and non-classical P4 pathways.

FSH up-regulates angiogenic factors in luteal cells of buffaloes

Follicle-stimulating hormone has been widely used to induce superovulation in buffaloes and cows and usually triggers functional and morphologic alterations in the corpus luteum (CL). Several studies have shown that FSH is involved in regulating vascular development and that adequate angiogenesis is essential for normal luteal development. Angiogenesis is regulated by many growth factors, of which vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2) have an established central role. Therefore, we have used a combination of in vitro and in vivo studies to assess the effects of FSH on the expression of VEGF and FGF2 and their receptors in buffalo luteal cells. The in vivo model consisted of 12 buffalo cows, divided into control (n = 6) and superovulated (n = 6) groups, and CL samples were collected on day 6 after ovulation. In this model, we analyzed the gene and protein expression of FGF2 and its receptors and the protein expression of VEGFA systems with the use of real-time PCR, Western blot analysis, and immunohistochemistry. In the in vitro model, granulosa cells were collected from small follicles (diameter, 4-6 mm) of buffaloes and cultured for 4 d in serum-free medium with or without FSH (10 ng/mL). To induce in vitro luteinization, LH (250 ng/mL) and fetal bovine serum (10%) were added to the medium, and granulosa cells were maintained in culture for 4 d more. The progesterone concentration in the medium was measured at days 4, 5, and 8 after the beginning of cell culture. Cells were collected at day 8 and subjected to real-time PCR, Western blot analysis, and immunofluorescence for assessment of the expression of FGF2, VEGF, and their receptors. To address the percentage of steroidogenic and growth factor-expressing cells in the culture, flow cytometry was performed. We observed that in superovulated buffalo CL, the FGF2 system mRNA expression was decreased even as protein expression was increased and that the VEGF protein was increased (P < 0.05). In vitro experiments with granulosa cells showed an increase in the mRNA expression of VEGF and FGF2 and its receptors 1 and 2 and protein expression of VEGF, kinase insert domain receptor, FGF receptor 2, and FGF receptor 3 in cells treated with FSH (P < 0.05), in contrast to the in vivo experiments. Moreover, the progesterone production by FSH-treated cells was elevated compared with untreated cells (P < 0.05). Our findings indicate that VEGF, FGF2, and their receptors were differentially regulated by FSH in vitro and in vivo in buffalo luteal cells, which points toward a role of CL environment in modulating cellular answers to gonadotropins.

Heat stress effects on the cumulus cells surrounding the bovine oocyte during maturation: altered matrix metallopeptidase 9 and progesterone production

When the effects of heat stress are detrimental during maturation, cumulus cells are intimately associated with the oocyte. To determine the extent to which heat stress affects these cells, in this study, transcriptome profiles of the cumulus that surrounded control and heat-stressed oocytes (41 °C during the first 12 h only and then shifted back to 38.5 °C) duringin vitromaturation (IVM) were compared using Affymetrix bovine microarrays. The comparison of cumulus-derived profiles revealed a number of transcripts whose levels were increased (n=11) or decreased (n=13) ≥ twofold after heat stress exposure (P<0.01), sufficient to reduce the development of blastocysts by 46.4%. In a separate study, quantitative PCR (qPCR) was used to confirm heat-induced differences in the relative abundances of the transcripts of five different genes (caveolin 1, matrix metallopeptidase 9, FSH receptor, Indian hedgehog homolog, and inducible nitric oxide synthase). Heat stress exposure resulted in >1.7-fold decrease in the protein levels of latent matrix metallopeptidase 9 (proMMP9). Heat-induced reductions in transcript levels were noted at 6 h IVM with reductions in proMMP9 protein levels at 18 h IVM (P=0.0002). Independent of temperature, proMMP9 levels at 24 h IVM were positively correlated with the development rate of blastocysts (R2=0.36;P=0.002). The production of progesterone increased during maturation; heat-induced increases were evident by 12 h IVM (P=0.002). Both MMP9 and progesterone are associated with the developmental competence of the oocyte; thus, it seems plausible for some of the negative consequences of heat stress on the cumulus–oocyte complex to be mediated through heat-induced perturbations occurring in the surrounding cumulus.

Characterization, neurosteroid binding and brain distribution of human membrane progesterone receptors δ and {epsilon} (mPRδ and mPR{epsilon}) and mPRδ involvement in neurosteroid inhibition of apoptosis

Three members of the progestin and adipoQ receptor (PAQR) family, PAQR-7, PAQR-8, and PAQR-5 [membrane progesterone (P4) receptor (PR) (mPR)α, mPRβ, and mPRγ], function as plasma mPRs coupled to G proteins in mammalian cells, but the characteristics of two other members, PAQR6 and PAQR9 (mPRδ and mPRε), remain unclear, because they have only been investigated in yeast expression systems. Here, we show that recombinant human mPRδ and mPRε expressed in MDA-MB-231 breast cancer cells display specific, saturable, high-affinity [(3)H]-P4 binding on the plasma membranes of transfected cells with equilibrium dissociation constants (K(d)s) of 2.71 and 2.85 nm, respectively, and low affinity for R5020, characteristics typical of mPRs. P4 treatment increased cAMP production as well as [(35)S]-guanosine 5'-triphosphate (GTP)γS binding to transfected cell membranes, which was immunoprecipitated with a stimulatory G protein antibody, suggesting both mPRδ and mPRε activate a stimulatory G protein (Gs), unlike other mPRs, which activate an inhibitory G protein (Gi). All five mPR mRNAs were detected in different regions of the human brain, but mPRδ showed greatest expression in many regions, including the forebrain, hypothalamus, amygdala, corpus callosum, and spinal cord, whereas mPRε was abundant in the pituitary gland and hypothalamus. Allopregnanolone and other neurosteroids bound to mPRδ and other mPRs and acted as agonists, activating second messengers and decreased starvation-induced cell death and apoptosis in mPRδ-transfected cells and in hippocampal neuronal cells at low nanomolar concentrations. The results suggest that mPRδ and mPRε function as mPRs coupled to G proteins and are potential intermediaries of nonclassical antiapoptotic actions of neurosteroids in the central nervous system.

In vivo and in vitro environmental effects on mammalian oocyte quality

The oocyte is at the center of the equation that results in female fertility. Many factors influence oocyte quality, including external factors such as maternal nutrition, stress, and environmental exposures, as well as ovarian factors such as steroids, intercellular communication, antral follicle count, and follicular fluid composition. These influences are interconnected; changes in the external environment of the female translate into ovarian changes that affect the oocyte. The lengthy period during which the oocyte remains arrested in the ovary provides ample time and opportunity for environmental factors to take their toll. An appropriate environment for growth and maturation of the oocyte, in vivo and in vitro, is critical to ensure optimal oocyte quality, which determines the success of fertilization and preimplantation embryo development, and has long-term implications for implantation, fetal growth, and offspring health.

Expression of nuclear progesterone receptor and progesterone receptor membrane components 1 and 2 in the oviduct of cyclic and pregnant cows during the post-ovulation period

BACKGROUND

Progesterone (P4) may modulate oviductal functions to promote early embryo development in cattle. In addition to its nuclear receptor (PR), P4 may mediate its actions through P4 receptor membrane component 1 (PGRMC1) and its relative, PGRMC2. Two successive experiments were undertaken to characterise the expression of PR, PGRMC1 and PGRMC2 in the bovine oviduct during the post-ovulation period, and to relate their expression to the presence of an embryo, the proximity of the CL and to the region of the oviduct.

METHODS

In the first experiment (Exp. I), whole oviduct sections were collected from Holstein cows at Day 1.5, Day 4 and Day 5 post-ovulation (n = 2 cows per stage). The expression of PR, PGRMC1 and PGRMC2 was studied in the ampulla and isthmus by RT-PCR, western-blot and immunohistochemistry. In Exp. II, oviduct epithelial cells were collected from cyclic and pregnant Charolais cows (n = 4 cows per status) at Day 3.5 post-ovulation and mRNA expression of PR, PGRMC1 and PGRMC2 was examined in the ampulla and isthmus by real-time quantitative PCR.

RESULTS

In Exp. I, PR, PGRMC1 and PGRMC2 were expressed in all oviduct samples. PGRMC1 was mainly localised in the luminal epithelium whereas PR and PGRMC2 were localised in the epithelium as well as in the muscle and stroma layers of the oviduct. The expression was primarily nuclear for PR, primarily cytoplasmic for PGRMC1 and both nuclear and cytoplasmic for PGRMC2. In Exp. II, mRNA levels for PR, PGRMC1 and PGRMC2 were not affected by either the pregnancy status or the side relative to the CL. However, the expression of PR and PGRMC2 varied significantly with the region of the oviduct: PR was more highly expressed in the isthmus whereas PGRMC2 was more highly expressed in the ampulla.

CONCLUSIONS

This is the first evidence of PGRMC2 expression in the bovine oviduct. Our findings suggest that P4 regulates the functions of the bovine oviduct in a region-specific manner and through both classical and non classical pathways during the post-ovulation period.

Progesterone directly and rapidly inhibits GnRH neuronal activity via progesterone receptor membrane component 1

GnRH neurons are essential for reproduction, being an integral component of the hypothalamic-pituitary-gonadal axis. Progesterone (P4), a steroid hormone, modulates reproductive behavior and is associated with rapid changes in GnRH secretion. However, a direct action of P4 on GnRH neurons has not been previously described. Receptors in the progestin/adipoQ receptor family (PAQR), as well as progesterone receptor membrane component 1 (PgRMC1) and its partner serpin peptidase inhibitor, clade E (nexin, plasminogen activator inhibitor type 1) mRNA binding protein 1 (SERBP1), have been shown to mediate rapid progestin actions in various tissues, including the brain. This study shows that PgRMC1 and SERBP1, but not PAQR, are expressed in prenatal GnRH neurons. Expression of PgRMC1 and SERBP1 was verified in adult mouse GnRH neurons. To investigate the effect of P4 on GnRH neuronal activity, calcium imaging was used on primary GnRH neurons maintained in explants. Application of P4 significantly decreased the activity of GnRH neurons, independent of secretion of gamma-aminobutyric acidergic and glutamatergic input, suggesting a direct action of P4 on GnRH neurons. Inhibition was not blocked by RU486, an antagonist of the classic nuclear P4 receptor. Inhibition was also maintained after uncoupling of the inhibitory regulative G protein (G(i/o)), the signal transduction pathway used by PAQR. However, AG-205, a PgRMC1 ligand and inhibitor, blocked the rapid P4-mediated inhibition, and inhibition of protein kinase G, thought to be activated downstream of PgRMC1, also blocked the inhibitory activity of P4. These data show for the first time that P4 can act directly on GnRH neurons through PgRMC1 to inhibit neuronal activity.

Influence of progesterone on oocyte quality and embryo development in cows

In cattle, the majority of embryo loss occurs very early during pregnancy (approximately Day 16), around or prior to maternal recognition of pregnancy. The actions of P4 in controlling LH pulsatility and ovarian follicular development may impinge negatively on oocyte quality. A considerable proportion of embryo loss may be attributable to inadequate circulating progesterone (P4) concentrations and the subsequent downstream consequences on endometrial gene expression and histotroph secretion into the uterine lumen. Conceptus growth and development require the action of P4 on the uterus to regulate endometrial function, including conceptus-maternal interactions, pregnancy recognition, and uterine receptivity for implantation. This review summarizes recent data highlighting the role of progesterone in determining oocyte quality and embryo development in cattle.

Immunopharmacology of ulipristal as an emergency contraceptive

A new progesterone antagonist, ulipristal has been made available as an emergency contraceptive. Ulipristal’s major mechanism of action as an emergency contraceptive has been ascribed to its ability to delay ovulation beyond the life span of the sperm. This paper analyzes the potential action of ulipristal (1) when unprotected intercourse and administration of ulipristal occur outside the fertility window and (2) when unprotected intercourse and administration of ulipristal occur at or within 24 hours of ovulation. When unprotected intercourse and the use of a single low dose of ulipristal occur outside of the fertility window, ulipristal behaves like a placebo. When unprotected intercourse and the use of a single low dose of ulipristal occur within the fertility window but before ovulation, ulipristal behaves like an emergency contraceptive by delaying ovulation and thereby preventing fertilization. When unprotected intercourse and the administration of ulipristal occur at or within 24 hours of ovulation, then ulipristal has an abortifacient action. It is proposed that the abortifacient mechanism of a low dose of ulipristal taken after fertilization but before implantation is due to the ability of ulipristal to block the maternal innate immune system to become immunotolerant to the paternal allogenic embryo. Progesterone’s critical immunotolerant actions involving early pregnancy factor, progesterone-induced blocking factor, and uterine natural killer cells are compromised by ulipristal.

Expression of progesterone receptor membrane component-1 in bovine reproductive system during estrous cycle

Several reports suggest the participation of progesterone receptor membrane component 1 (PGRMC1) in progesterone signaling in the reproductive system. This study aimed at investigating the presence and localization of PGRMC1 in bovine ovary, oviduct and uterus, during the follicular and luteal phases of the estrous cycle. In the ovary, PGRMC1 has been detected in surface germinal epithelium, granulosa cells, theca cells and in the germinal vesicle of the oocytes at all stages of folliculogenesis. In the corpus luteum the expression of PGRMC1 was influenced by the stage of the estrous cycle. In the oviducts and in the uterus horns, PGRMC1 was immunolocalized in the luminal epithelium, in the muscle layer cells and in the endothelial cells. In the uterus, PGRMC1 was intensely localized also in the glandular endometrium. However, in the oviducts and in the uterus horns, the localization of PGRMC1 was independent on the stage of the estrous cycle and on whether evaluating the ipsilateral or the contralateral organ. In conclusion, the present immunohistochemical study showed that PGRMC1 is located in various compartments of the bovine female reproductive organs. With the exception of the corpora lutea, PGRMC1 localization showed similar pattern during different stages of the estrous cycle.