Effects of IGF-1, TGF-alpha plus TGF-beta1 and bFGF on in vitro survival, growth and apoptosis in FSH-stimulated buffalo (Bubalis bubalus) preantral follicles

Growth factors and female reproduction in vertebrates

Female reproductive efficiency is influenced by the outcomes of various processes, including folliculogenesis, apoptosis, response to gonadotropin signaling, oocyte maturation, and ovulation. The role of hormones in regulating these processes and other reproductive activities has been well established. It is becoming increasingly evident that in addition to well-characterized hormones, growth factors play vital roles in regulating some of these reproductive activities. Growth factors and their receptors are widely distributed in vertebrate ovaries at different stages of ovarian development, indicating their involvement in intraovarian reproductive functions. In the ovary, cell surface receptors allow growth factors to regulate intraovarian reproductive activities. Understanding these actions in the reproductive axis would provide a tool to target growth factors and/or their receptors to yield desirable reproductive outcomes. These include enrichment of in vitro maturation and fertilization culture media, and management of infertility. This review discusses some widely characterized growth factors belonging to the TGF, EGF, IGF, FGF, and BDNF family of peptides and their role in female reproduction in vertebrates, with a focus on mammals.

Insulin-like growth factor (IGF) performance in ovarian function and applications in reproductive biotechnologies

The role of the insulin-like growth factor (IGF) system has attracted close attention. The activity of IGF binding proteins (IGFBPs) within the ovary has not been fully elucidated to date. These proteins bind to IGF with an equal, or greater, affinity than to the IGF1 receptor, thus being in the main position to regulate IGF signalling, in addition to extending the half-life of IGFs within the bloodstream and promoting IGF storage in specific tissue niches. IGF1 has an important part in cell proliferation, differentiation and apoptosis. Considering the importance of IGFs in oocyte maturation, this review sought to elucidate aspects including: IGF production mechanisms; constituent members of their family and their respective functions; the role that these factors play during folliculogenesis, together with their functions during oocyte maturation and apoptosis, and their performance during luteal development. This review also explores the role of IGFs in biotechnological applications, focusing specifically on animal genetic gain.

Clinical characteristics and risk factors of ovarian reserve decreases in women with Crohn's disease: a case-control study

BACKGROUND

Crohn's disease (CD), often occurring in women of child-bearing age, can decline the fertility rate. However, whether it reduces ovarian reserve has been rarely reported. This study aimed to evaluate the ovarian reserve in women with CD from the perspective of anti-Müllerian hormone (AMH), and explore the factors that can decrease ovarian reserve.

METHODS

A case-control retrospective study was designed. We analyzed the AMH levels in a total of 135 CD women and 878 healthy controls. Through propensity score matching, the subjects were assigned in a ratio of 1:3 to CD group (n = 121) and control group (n = 324). Both groups shared similar basic characteristics, like age, body mass index and smoking status. Serum AMH levels were measured by chemiluminescence.

RESULTS

The AMH level in the CD group was significantly lower than that in the control group (2.17 ± 2.23 μg/L vs 3.95 ± 2.01 μg/L, 95%CI [1.34-2.21], P < 0.001). In both groups, the AMH levels decreased as age increased, but without between-group difference in the decreasing rate (P = 0.639). Multivariate analysis showed that age > 30 years (OR, 2.905; 95%CI [1.053-8.531], P = 0.017), disease activity (OR,4.314; 95%CI [1.561-12.910], P = 0.002) and thalidomide use (OR,12.628; 95%CI [4.351 -42.820], P < 0.001) were independent risk factors associated with decreased ovarian reserve (AMH<1.1μg/L).

CONCLUSION

Ovarian reserve is lower in CD women than in healthy women. Age, CD activity and medication of thalidomide are risk factors that can aggravate the decline of ovarian reserve.

Expression of Hormones, Cytokines, and Antioxidants in Heat-Stressed Subfertile Female Dromedaries

Simple Summary

Heat stress imposes a high burden on domestic animals’ productive and reproductive performance. Due to the long hot summer, drought, and shortage of green fodders, camels raised in the desert suffer a lot of reproductive inefficiencies. This animal represents one of the main wealth sources for the desert inhabitants. Several fertility disorders have been discovered, leading to frequent breeding without pregnancy. This study aimed at exploring blood metabolites such as metabolic and reproductive hormones, cytokines, and antioxidants to be monitored as bio-indictors for subfertility in female camels. The results confirmed that none of the tested metabolic hormones and glucose revealed differences among fertile and subfertile females. However, FSH, inhibin, IL-ß, nitrous oxide, and glutathione revealed remarkable differences between fertile and subfertile females, which would be reliable tools to predict subfertility statuses in this animal. IL-ß revealed higher levels in the cases with genital inflammations. The normal profiles in control females revealed the highest FSH, and the lowest inhibin were vice versa in all subfertile females. Nonetheless, nitrous oxide and glutathione would also be reliable bio-indicators for judging the fertility status.

Abstract

The prevailing hot climate imposes heavy burdens on the productivity of the camel, goat, and sheep herds raised in the Gulf desert. Due to the lack of a reliable indicator for the various subfertility statuses in camel females, this study aimed to investigate the expression of inhibin, TGFά, ILß, FSH, sex and metabolic hormones, and antioxidants for the fertility status in camel females. Eighty-two subfertile and five fertile females were admitted to the university clinic with the complaint of repeat breeding with failed conception. The animal’s genital tracts were examined for reproductive soundness. Blood samples were withdrawn for hormonal, cytokines, and antioxidants determinations. Subfertile females were categorized into six groups; endometritis (EN, 28), inactive ovaries (IO, 20), ovarian hydrobursitis (BU, 19), vaginal adhesions (VA, 7), salpingitis (SA, 4), and cervicitis (CE, 4). Results revealed a significant increase in inhibin in all groups compared to control (68.2, 66.4, 61.8. 58.8, 58.3, 55.8, and 36 pg/mL, in CE, VA, IO, BU, EN, SA, and CON, respectively). TGFά, dehydroepiandrosterone (DHEA), and progesterone were not different among groups, whereas IL-ß differed among groups. FSH, estradiol, nitrous oxide, and glutathione were higher in CON compared with other groups. In conclusion, reproductive failures in camel females are reflected in the imbalances of endocrine, cytokines, and antioxidants bio-indicators.

Drug-free in vitro activation combined with 3D-bioprinted adipose-derived stem cells restores ovarian function of rats with premature ovarian insufficiency

BACKGROUND

Emerging drug-free in vitro activation (IVA) technique enables patients with premature ovarian insufficiency (POI) to restore ovarian function and conceive their own genetic offspring. However, various issues have greatly restricted its clinical application. Transplantation of adipose-derived stem cells (ADSCs) has promising roles in restoring ovarian function of rats with POI, but insufficient retention has greatly hampered their efficiency. Here, we designed a 3D-bioprinted engineering ovary composed of drug-free IVA and ADSCs, which may prolong the retention of ADSCs and construct an early vascular microenvironment, thus compensating for the disadvantages of drug-free IVA to some extent and ameliorating impaired ovarian function in the POI rats.

METHODS

After intraperitoneal injection of cyclophosphamide, the POI model rats were randomized into 5 groups: (1) POI group; (2) ovarian fragments group; (3) 3D scaffold combined with ovarian fragments group; (4) ovarian fragments combined with ADSCs group; (5) 3D scaffold with ADSCs combined with ovarian fragments as 3D-bioprinted engineering ovary group. Normal rats were identified as the control group. The localization of CM-Dil-labeled ADSCs and co-localization with CD31 were observed to examine the distribution and underlying mechanism of differentiation. Histomorphological and immunohistochemical analyses were performed to calculate follicle number and assess proliferation and apoptosis of granulosa cells (GCs). Immunofluorescence staining was used to evaluate angiogenesis. Hormone levels were measured to evaluate the restoration of endocrine axis. Western blot analysis and RT-PCR were conducted to explore the potential mechanism.

RESULTS

CM-Dil-labeled ADSCs were distributed in the interstitium of ovaries and had significantly higher retention in the 3D-bioprinted engineering ovary group. Several regions of the co-staining for CM-Dil and CD31 were in the area of vascular endothelial cells. Meanwhile, the follicle counts, GCs proliferation, neoangiogenesis, and hormone levels were significantly improved in the 3D-bioprinted engineering ovary group, as compared with other groups. Furthermore, the ovarian function was ameliorated and angiogenesis was promoted through regulating the PI3K/AKT pathway.

CONCLUSION

Our results suggested that 3D-bioprinted engineering ovary had great potential for restoring impaired ovarian function of rats with POI, which could compensate for the disadvantages of drug-free IVA to some extent.

Follicular wave dynamics and Growth factors gene expression in Braford heifers

The objectives of the present study were (experiment 1) to characterized development and dynamics of the dominant follicles (DF) and the corpus luteum (CL) to determine patterns of two (W2) and three (W3) follicular waves in beef heifers, and (experiment 2) to determine gene expression of growth factors gene expression in follicular cells of W2 and W3 heifer. Twenty-eight Braford heifers were used. Dominant follicular and CL were monitored daily by ultrasonography to identify the development W2 and W3 in heifers. Pre-ovulatory DF were aspirated on day 19 in W2 and on day 22 in W3 heifers. In W2 and W3, follicular cells (FC) of gene expression of growth differentiation factor 9, bone morphogenetic protein 15 (BMP15), fibroblast growth factor basic, transforming growth factor beta receptor 1, bone morphogenetic protein receptor type IB and fibroblast growth factor receptor 2 were evaluated. The regression of the DF of the first follicular wave and the emergency of the DF of the second follicular wave began later in the heifers W2 than in W3 (p = .02 and p < .01). The regression of the CL began earlier in the W2 than in W3 group (p < .01). Gene expression of growth factors and receptors was similar between groups. However, higher relative levels of BMP15 was observed in W2 group (p = .07). Results propose that wave patterns were regulated by the development time of the DF in the first wave and the life of the CL. Furthermore, higher levels of BMP15 could produce shorter life of CL. The present work suggest that ultrasonography associated with molecular assays could be used as an easy and effective tool to characterize follicular wave patterns.

Risk Factors Associated with Impaired Ovarian Reserve in Young Women of Reproductive Age with Crohn's Disease

BACKGROUND/AIMS

Crohn's disease (CD) primarily affects young female adults of reproductive age. Few studies have been conducted on this population's ovarian reserve status. The aim of study was to investigate potential risk factors associated with low ovarian reserve, as reflected by serum anti-Müllerian hormone (AMH) in women of reproductive age with CD.

METHODS

This was a case-control study. Cases included 87 patients with established CD, and healthy controls were matched by age, height and weight in a 1:1 ratio. Serum AMH levels were measured by enzyme-linked immunosorbent assay.

RESULTS

The average serum AMH level was significantly lower in CD patients than in control group (2.47±2.08 ng/mL vs. 3.87±1.96 ng/mL, respectively, P<0.001). Serum AMH levels were comparable between CD patients and control group under 25 years of age (4.41±1.52 ng/mL vs. 3.49±2.10 ng/mL, P=0.06), however, serum AMH levels were significantly lower in CD patients over 25 years of age compared to control group (P<0.05). Multivariable analysis showed that an age greater than 25 (odds ratio [OR], 10.03; 95% confidence interval [CI], 1.90-52.93, P=0.007), active disease state (OR, 27.99; 95% CI, 6.13-127.95, P<0.001) and thalidomide use (OR, 15.66; 95% CI, 2.22-110.65, P=0.006) were independent risk factors associated with low ovarian reserve (serum AMH levels <2 ng/mL) in CD patients.

CONCLUSIONS

Ovarian reserve is impaired in young women of reproductive age with CD. Age over 25 and an active disease state were both independently associated with low ovarian reserve. Thalidomide use could result in impaired ovarian reserve.

Insulin-like growth factor-1 (IGF-1) promotes primordial follicle growth and reduces DNA fragmentation through the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signalling pathway

We investigated the effects of insulin-like growth factor 1 (IGF-1) on the morphology and follicular activation of ovine preantral follicles cultured in situ and whether the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway is involved in IGF-1 action in the sheep ovary. Ovine ovarian fragments were fixed for histological and terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) analyses (fresh control) or cultured in supplemented alpha-minimum essential medium (α-MEM+; control) or α-MEM+ with IGF-1 (1, 10, 50, 100 or 200ngmL-1) for 7 days. Follicles were classified as normal or atretic, primordial or growing and the oocyte and follicle diameters were measured. DNA fragmentation was evaluated by TUNEL assay. Proliferating cell nuclear antigen (PCNA) immunohistochemistry was performed on the fresh control, α-MEM+ and 100ngmL-1 IGF-1 samples. Inhibition of PI3K activity was performed through pretreatment with the PI3K inhibitor LY294002 and phosphorylated AKT (pAKT) expression was analysed after culture in the absence or presence of LY294002. IGF-1 at 100ngmL-1 increased (P<0.05) follicular activation compared with α-MEM+ and decreased TUNEL-positive cells (P<0.05) compared with other treatments. PCNA-positive cells also increased (P<0.05) in 100ngmL-1 IGF-1. LY294002 significantly inhibited follicular activation stimulated by α-MEM+ and 100ngmL-1 IGF-1 and reduced pAKT expression in follicles. Overall, IGF-1 at 100ngmL-1 promoted primordial follicle activation, cell proliferation and reduced DNA fragmentation after in situ culture through the PI3K/AKT pathway.

Effects of stem cell factor on in vitro growth of buffalo oocytes

Stem cell factor (SCF) plays important roles in primordial follicle activation, oocyte growth and survival, granulosa cell proliferation, theca cell recruitment, and ovarian steroidogenesis. The aim of this study was to investigate the effect of SCF on in vitro growth of buffalo oocytes. Oocyte-granulosa cell complexes (OGCs) were dissected from early antral follicles of slaughtered buffalo ovaries and cultured for 6 days in media supplemented with 0, 50 or 100 ng/mL SCF. In vitro grown oocytes were further cultured for in vitro maturation for 24 h. The results showed that SCF significantly (P < 0.05) increased oocyte diameter in vitro. The percentages of surviving oocytes were 60, 81 and 92 in 0, 50 and 100 ng/mL SCF supplemented group, respectively. SCF promoted formation of antrum-like structures in culture. The results also showed that SCF enhanced the maturation of in vitro grown buffalo oocytes. Here, 14% in vitro grown oocytes reached metaphase II (MII) stage in 50 ng/mL SCF supplemented group, whereas the percentage was increased to 26% in 100 ng/mL SCF treated group. These results show that SCF supports the growth, viability and nuclear maturation of buffalo oocytes in vitro.

Therapeutic effects of human umbilical cord mesenchymal stem cell-derived microvesicles on premature ovarian insufficiency in mice

BACKGROUND

Premature ovarian insufficiency (POI) is one of the leading causes of female infertility, which is caused by an abnormal ovarian reserve. Currently, there is no effective treatment to restore the fertility of POI patients. Recent studies suggested that microvesicles (MVs) released from mesenchymal stem cells (MSCs) exert therapeutic effects in various degenerative diseases. In this study, the effect of human umbilical cord MSC-derived MVs (HUCMSC-MVs) on the restoration of ovarian function in a chemotherapy-induced POI mouse model is investigated.

METHODS

MVs were obtained from the supernatant of cultured HUCMSCs. The localization of PKH26-labeled HUCMSC-MVs in ovarian tissues was observed by confocal laser scanning microscopy. Histomorphometric analysis was performed to count the number of ovarian follicles and vessels. The ovarian sections were stained with anti-CD34 to evaluate angiogenesis. The levels of estradiol (E2) and follicle-stimulating hormone (FSH) were measured by enzyme-linked immunosorbent serologic assay. The mRNA expression of angiogenesis-related cytokines and the protein expression of AKT in mouse ovaries were measured by quantitative RT-PCR and western blot analysis. The parametric variables were compared by Student's t test and analysis of variance. The non-parametric variables were compared by the Mann-Whitney U test. Categorical variables were compared by χ² test. P < 0.05 was considered statistically significant.

RESULTS

PKH26-labeled HUCMSC-MVs were detectable within the ovaries and migrated to the ovarian follicles 24 h after transplantation. The transplantation of HUCMSC-MVs could increase the body weight and number of ovarian follicles (primordial, developing, and preovulatory follicles), induce ovarian angiogenesis, and recover the disturbed estrous cycle of POI mice. The expression levels of total AKT, p-AKT, and angiogenic cytokines (including VEGF, IGF, and angiogenin) in the ovaries of POI mice were markedly upregulated after HUCMSC-MVs transplantation, suggesting that HUCMSC-MVs transplantation might recover ovarian function by inducing angiogenesis via the PI3K/AKT signaling pathway.

CONCLUSIONS

This study provides valuable insight into the effects of HUCMSC-MVs on ovarian tissue angiogenesis and on the restoration of ovarian function in POI mice, which may be helpful to develop a treatment strategy for POI patients.

In vitro survival, growth, and maturation of sheep oocytes from secondary follicles cultured in serum-free conditions: impact of a constant or a sequential medium containing recombinant human FSH

This study evaluated the in vitro development and maturation of ovine oocytes from secondary follicles cultured in serum-free medium containing fixed or sequential concentrations of recombinant human FSH (rhFSH). Follicles were cultured in α-MEM⁺ alone or with constant (500, 750, or 1,000 ng/mL) or sequential concentrations of rhFSH (seq. 1: day 6 = 500; day 12 = 750; day 18 = 1,000 ng/mL and seq. 2: day 6 = 100; day 12 = 500; day 18 = 1,000 ng/mL). At the end of the experiment, follicular survival was higher (P < 0.05) in 750 ng/mL rhFSH than the control and 1,000 ng/mL rhFSH. As early as day 6 of culture, antral cavity formation was observed in all treatments. Follicular diameter increased progressively and significantly in all treatments throughout 18 d of culture. Furthermore, addition of rhFSH to the medium promoted a significant increase in the percentage of fully grown oocytes in all treatments compared to α-MEM⁺. Mitochondrial activity was higher in rhFSH treatments than in the control, except in rhFSH seq. 2 (P < 0.05). Maturation rates increased in oocytes from intact follicles cultured in 750 ng/mL rhFSH compared to the control (P < 0.05). In conclusion, rhFSH at 750 ng/mL maintained the survival of secondary follicles cultured in serum-free medium, improved oocyte growth, mitochondrial activity, and oocyte maturation.

Thalidomide results in diminished ovarian reserve in reproductive age female IBD patients

The effectiveness of thalidomide in treating inflammatory bowel disease (IBD) has been widely recognized. Meanwhile, many serious adverse drug reactions have been observed, but no know reports on ovarian reserve function.Female patients, ranging in age between 18 and 40, were referred to our institution to undergo sex hormone detection and ultrasonic scanning for ovarian function assessment, between February 1, 2016 and September 31, 2016.Thirty-three patients treated with thalidomide (group A), 73 patients without thalidomide (group B), and 78 healthy women as control were studied. Menstrual disorder was higher in group A than group B (78.8% vs 57.2%, P < 0.05), and both groups were higher than control group 33.3%, P < 0.05. Anti-Mullerian hormone (AMH) levels and antral follicle count (AFC) in group A were lower than group B, P < 0.05, while estradiol (E2) and follicle-stimulating hormone (FSH) levels were no different between 2 groups. Crohn Disease Endoscopic Index of Severity (CDEIS) and thalidomide were the independent risk factors in diminished ovarian reserve (DOR), and when dose reached 75 mg/day, 5 g total, or when treatment time reached 10 months respectively. These influence may increasing (P < 0.05), but they may recover after stopping (P < 0.05).Thalidomide was an independent risk factor leading to DOR in female IBD patients, the influence may increasing when daily dose and accumulated dose reached 75 mg/day and 5 g total dose, but may be reversed by stopping.

Fibroblast growth factor 2 (FGF2) and vascular endothelial growth factor A (VEGFA) synergistically promote steroidogenesis and survival of cultured buffalo granulosa cells

The present study investigated the combined effect of fibroblast growth factor 2 (FGF2) and vascular endothelial growth factor A (VEGF-A) on estradiol (E₂) secretion and relative abundance of mRNA for aromatase enzyme (CYP19A1), proliferating cell nuclear antigen (PCNA) and BCL-2 associated X protein (BAX) in cultured buffalo granulosa cells (GCs). Follicles were isolated and classified into four groups based on size and E₂ concentration in follicular fluid (FF): Small, 4-6mm diameter, E₂<0.5ng/ml; Medium, 7-9mm, E₂=0.5-5ng/ml; Large, 10-13mm, E₂=5-40ng/ml; Preovulatory (PFs), >14mm, E₂>180ng/ml. The GCs of PF were cultured in 24 well cell culture plates and allowed to become 75-80% confluent. Then cultured GCs were treated with FGF2 (200ng/ml) and VEGF-A (100ng/ml) separately and in combination for three incubation periods (24, 48 and 72h). Estradiol secretion was greater in GCs treated with FGF2+VEGF-A compared to FGF2 or VEGF-A at all incubation periods and was greatest (P<0.05) at 72h of incubation. The relative abundance of CYP19A1 and PCNA mRNA were relatively consistent with the amount E₂ secretion. In contrast, the relative abundance of Bax mRNA was less in GCs treated with the combination of FGF2 and VEGF-A as compared to either FGF2 or VEGF-A alone and the least concentration (P<0.05) was at 72h of incubation. Findings with use of immunocytochemistry of cells treated with these factors were consistent to the relative abundance of mRNA transcript for the factor. The present findings indicate that FGF2 and VEGF-A may function in a synergistic manner to promote steroidogenesis and survival of cultured buffalo GCs.

Short-term methionine supplementation during the early post-partum period in primiparous rabbits improves prolificacy associated with an increase in serum concentrations of IGF-I

The aim of this study was to evaluate the effects of methionine supplementation on energy metabolism and reproductive performance during the early post-partum period in primiparous does. Forty nulliparous New Zealand White does were used. Females were randomized in two groups at calving: the control group (n = 20) was fed with the basal diet, and the methionine group (n = 20) was fed the basal diet plus 1 g/animal/day of methionine from the day of calving to 4 days post-partum. Results showed that methionine supplementation increased (p = 0.032) the concentration of insulin-like growth factor-1 with respect to control group 4 days post-partum. It similarly increased the prolificacy (p = 0.03), the number of kits born alive per litter (p = 0.06) and the body gain weight of the litter during supplementation (p = 0.035). These results were observed despite the does in the methionine group having a deeper negative energy balance than the does in the control group. Finally, methionine supplementation did not affect receptivity (p = 0.23), fertility (p = 0.49), the number of kits born dead per litter (p = 0.86) insulin and metabolites as glucose, non-esterified fatty acids and triglycerides. In conclusion, our results show that methionine supplementation during the first 4 days of the post-partum period in rabbits increases total litter size and the corporal weight of kits and is associated with an increase in blood concentration of IGF-1.

Ovarian follicle development in vitro and oocyte competence: advances and challenges for farm animals

During the last 2 decades, research on in vitro preantral follicle growth and oocyte maturation has delivered fascinating advances concerning the knowledge of processes regulating follicle growth and the developmental competence of oocytes. These advances include (1) information about the role of several hormones and growth factors on in vitro activation of primordial follicles; (2) increased understanding of the intracellular pathway involved in the initiation of primordial follicle growth; (3) the growth of primary and secondary follicles up to antral stages; and (4) production of embryos from oocytes from in vitro grown preantral follicles. This review article describes these advances, especially in regard farm animals, and discusses the reasons that limit embryo production from oocytes derived from preantral follicles cultured in vitro.

Relative mRNA expression and immunolocalization for transforming growth factor-beta (TGF-β) and their effect on in vitro development of caprine preantral follicles

This study aimed to evaluate the immunolocalization and messenger RNA (mRNA) expression for transforming growth factor-beta (TGF-β) and its receptors (TGF-βRI and RII), as well as mRNA expression for P450 aromatase and FSH receptor in caprine preantral follicles. The effects of TGF-β, FSH alone, or in association on the in vitro follicular development were also assessed. Immunohistochemical analyses showed the expression of TGF-β and its receptors in oocytes of all follicle stages and granulosa cells of primary and secondary follicles. mRNA for TGF-β receptors and for FSH receptor (FSHR) was present in preantral follicles as well as in oocytes and granulosa cells of antral follicles. Isolated secondary follicles were cultured in α-minimum essential medium (MEM) alone or supplemented with either FSH (100 ng/ml), TGF-β (10 ng/ml), or TGF-β + FSH for 18 d. TGF-β increased significantly oocyte diameter when compared to FSH alone and control. After 18 d of culture, all groups showed a significant reduction in P450 aromatase and FSHR mRNA levels in comparison to fresh control. In contrast, treatment with FSH significantly increased the mRNA expression for TGF-β in comparison to fresh control and other treatments. In conclusion, the findings showed that TGF-β and its receptors are present in caprine ovarian follicles. Furthermore, they showed a positive effect on oocyte growth in vitro.

Transforming growth factor-β (TGF-β) maintains follicular ultrastructure and stimulates preantral follicle growth in caprine ovarian tissue cultured in vitro

The objectives of this study were to investigate whether TGF-β affect the survival, activation and further growth of goat primordial follicles enclosed in ovarian cortex after in vitro culture. Goat ovaries were collected from an abattoir and pieces of ovarian tissues were cultured for one or seven days in a supplemented alpha Minimum Essential Medium, alone or containing TGF-β (1, 5, 10 or 50ng/mL). Ovarian tissues from the fresh control as well as those cultured were processed for histological and ultrastructural studies. The results showed that when compared with fresh control, there was decrease in the percentages of histologically normal follicles in all treatments only after seven days culture. TGF-β did not affect the activation of preantral follicles regardless of its concentration, however, larger follicles diameter (P<0.05) was observed using 10ng/mL TGF-β than in the fresh control and other treatments. Moreover, this concentration maintained the normal ultrastructure after seven days of culture. In conclusion, TGF-β showed additional effect on the follicle growth and the maintenance of ultrastructural integrity of goat preantral follicles enclosed in ovarian tissue when used at 10ng/mL during seven days of culture.

The effect of calorie restriction on the presence of apoptotic ovarian cells in normal wild type mice and low-plasma-IGF-1 Laron dwarf mice

Background

It is known that caloric restriction extends lifespan and can minimize age-related dysfunction of the reproductive system. We became interested in how caloric restriction influences apoptosis, which is a crucial process that maintains ovarian cell homeostasis.

Methods

We examined ovarian cells in: 2.5-year-old wild type mice on caloric restriction (CR) or fed ad libitum (AL) and Laron dwarf mice (GHR-KO) at the same ages on CR or fed AL. Apoptosis was assessed by histochemical analysis on paraffin sections of ovarian tissue.

Results

Morphological and histochemical analysis revealed that CR improved reproductive potential in 2.5-year-old WT littermates and GHR-KO female mice, as indicated by the increased number of ovarian follicles. The level of apoptosis in ovarian tissue was higher in WT mice on a CR diet compared with WT mice on the AL diet. In GHR-KO mice, the level of apoptosis in ovaries was similar for mice on CR and on AL diets and bigger than in WT mice on CR.

Conclusions

Morphological and histochemical analysis revealed a younger biological age of the ovaries in 2-year-old WT littermates and GHR-KO female mice on CR compared with animals fed AL.

Prostaglandin E(2) and insulin-like growth factor I interact to enhance proliferation of theca externa cells from chicken prehierarchical follicles

The interactive effect of insulin-like growth factor I (IGF-I) and prostaglandin E2 (PGE2) on the proliferation of theca externa cells (TECs) was investigated in the prehierarchical small yellow follicles of laying hens. IGF-I manifested a proliferating effect like PGE2 on TECs, but this stimulating effect was restrained by AG1024 (IGF-IR inhibitor), KP372-1 (PKB/AKT inhibitor) or NS398 (COX-2 inhibitor). AG1024, KP372-1 or NS398 abolished IGF-I-stimulated COX-2 expression and PGE2 production. Meanwhile, KP372-1, NS398 or AG1024 depressed the PGE2-stimulated expression of COX-2 and IGF-IR mRNA. Therefore, the IGF-I receptor pathway up-regulates COX-2 expression and PGE2 synthesis via PKB signaling cascade, and then PGE2 stimulates IGF-IR mRNA expression to promote TEC proliferation in an autocrine pattern. Overall, the reciprocal stimulation of intracellular PGE2 and IGF-I may enhance TEC proliferation and facilitate the development of chicken prehierarchical follicles.

The effects of epidermal growth factor (EGF) on the in vitro development of isolated goat secondary follicles and the relative mRNA expression of EGF, EGF-R, FSH-R and P450 aromatase in cultured follicles

The effects of varying concentrations of EGF were evaluated in terms of in vitro follicular development and the mRNA expression levels of EGF, EGF-R, FSH-R and P450 aromatase. After 6 days, the addition of 50 ng/mL of EGF to the culture medium increased the antrum formation rates in comparison to cultured control and after 18 days of culture produced oocytes with higher rates of meiosis resumption when compared to the other treatments (P<0.05). The daily follicular growth rates in presence of EGF (50 or 100) were increased in comparison to the cultured control (P<0.05). Treatment with EGF 50 stimulated the expression of EGF mRNA but reduced EGF-R mRNA expression and estradiol secretion as compared to the cultured control (P<0.05). After 18 days of culture, the mRNA levels for FSH-R and P450 aromatase were greater than those of the non-cultured controls (P<0.05). In conclusion, the effects of EGF treatment on the mRNA levels for EGF, EGF-R, FSH-R, and P450 aromatase varied according to the stage of follicle development.

Caloric restriction promotes the reproductive capacity of female rats via modulating the level of insulin-like growth factor-1 (IGF-1)

The insulin-like growth factor-1 (IGF-1) plays an important role in the regulation of reproductive function. In the present study, we examined the effects of caloric restriction (CR) on the reproductive lifespan in rats and investigated the potential role of IGF-1. After 10 weeks of treatment, we determined the distribution of the ovarian follicles at various stages and measured the plasma level of IGF-1, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estrogen (ESG). Our results show that IGF-1 level was decreased after CR and correlated with the decrease in the levels of LH, FSH and ESG. Moreover, a higher percentage of primordial follicles and surviving follicles was observed in CR rats than in control rats (P<0.05). Immunohistochemical analysis showed that IGF-1 was extensively expressed in the cytoplasm of granulosa cells in the surviving follicles at different stages but not in the atretic follicles. Taken together, these results suggest that caloric restriction promotes the reproductive capacity of female rats via modulating the level of IGF-1, which then regulate pituitary gonadotrope cells to reduce the release of LH, FSH and ESG, and modulate follicular development.