Oestrogen receptor α and β, androgen receptor and progesterone receptor mRNA and protein localisation within the developing ovary and in small growing follicles of sheep

Effect of the gonadotropin surge on steroid receptor regulation in preovulatory follicles and newly formed corpora lutea in the cow

The objective of the study was to characterize the mRNA expression patterns of specific steroid hormone receptors namely, estrogen receptors (ESRRA-estrogen related receptor alpha and ESRRB-estrogen related receptor beta) and progesterone receptors (PGR) in superovulation-induced bovine follicles during the periovulation and subsequent corpus luteum (CL) formation. The bovine ovaries (n = 5 cow / group), containing preovulatory follicles or early CL, were collected relative to injection of the gonadotropin-releasing hormone (GnRH) at (I) 0 h, (II) 4 h, (III) 10 h, (IV) 20 h, (V) 25 h (preovulatory follicles) and (VI) 60 h (CL, 2-3 days after induced ovulation). In this experiment, we analyzed the steroid receptor mRNA expression and their localization in the follicle and CL tissue. The high mRNA expression of ESRRA, ESRRB, and PGR analyzed in the follicles before ovulation is significantly reduced in the group of follicles during ovulation (25 h after GnRH), rising again significantly after ovulation in newly formed CL, only for ESRRA and PGR (P < 0.05). Immunohistochemically, the nuclei of antral follicles' granulosa cells showed a positive staining for ESRRA, followed by higher activity in the large luteal cells just after ovulation (early CL). In contrast, the lower PGR immunopresence in preovulatory follicles increased in both small and large luteal cell nuclei after follicle ovulation. Our results of steroid receptor mRNA expression in this experimentally induced gonadotropin surge provide insight into the molecular mechanisms of the effects of steroid hormones on follicular-luteal tissue in the period close to the ovulation and subsequent CL formation in the cow.

Changes in ovarian tissue structure and distribution of oestrogen receptors in Huanghuai goats at different ages

To observe developmental changes in the ovarian tissue structure and distribution characteristics of oestrogen receptors (ERs) in the ovaries of Huanghuai goats at different ages, we selected healthy Huanghuai goats ewes and divided them into five groups (i.e. 3-, 30-, 60-, 90- and 120-day-old groups), with 10 animals in each group. The serum was separated after blood collection through the jugular vein, and the contents of oestrogen (E) and progesterone (P) in the serum of Huanghuai goats at each age were determined. Three goats were randomly selected from each group and sacrificed after anaesthesia, and the ovarian tissue was quickly obtained and placed in 4% paraformaldehyde fixative to prepare the tissue sections. Using HE, oestrogen receptors were immunohistochemically stained and observed. These results showed many primordial follicles and occasional secondary follicles in the ovaries of 3-day-old Huanghuai goats. Ovarian reticular structures were observed in 30-day-old ovarian medulla, with occasional near-mature growing follicles. Mature follicles and corpus luteum were occasionally detected in 60-day-old ovarian cortex. The 90-120-day-old ovarian cortices contained growing and mature follicles, and the number of mature follicles and corpora lutea increased, implying a significant luteal involution period. The E and P contents in the 120-day-old group were significantly higher than those in the 3-, 30-, 60- and 90-day-old groups. The levels of ERα and ERβ in the 3- and 30-day-old groups were mainly distributed in the granulosa cells of ovarian reproductive epithelial cells, primordial follicles, atretic follicles, and primary and secondary follicles. The ERα and ERβ levels of the 60-, 90- and 120-day-old groups were also distributed in the granulosa cells and luteal cells of mature follicles, especially in the 120-day-old endometrial cells of mature follicles, where ERβ was distributed significantly. The overall expression of ERβ in the ovary was higher than that of ERα. The results of this study provide basic data on the ovarian development and the specific expression of ERs and PRs in the ovaries of Huanghuai white goats, which play an important role in ovarian development and precocity.

Loss of ERβ Disrupts Gene Regulation in Primordial and Primary Follicles

Loss of ERβ increases primordial follicle growth activation (PFGA), leading to premature ovarian follicle reserve depletion. We determined the expression and gene regulatory functions of ERβ in dormant primordial follicles (PdFs) and activated primary follicles (PrFs) using mouse models. PdFs and PrFs were isolated from 3-week-old Erβ knockout (Erβnull) mouse ovaries, and their transcriptomes were compared with those of control Erβfl/fl mice. We observed a significant (≥2-fold change; FDR p-value ≤ 0.05) deregulation of approximately 5% of genes (866 out of 16,940 genes, TPM ≥ 5) in Erβnull PdFs; ~60% (521 out of 866) of the differentially expressed genes (DEGs) were upregulated, and 40% were downregulated, indicating that ERβ has both transcriptional enhancing as well as repressing roles in dormant PdFs. Such deregulation of genes may make the Erβnull PdFs more susceptible to increased PFGA. When the PdFs undergo PFGA and form PrFs, many new genes are activated. During PFGA of Erβfl/fl follicles, we detected a differential expression of ~24% genes (4909 out of 20,743; ≥2-fold change; FDR p-value ≤ 0.05; TPM ≥ 5); 56% upregulated and 44% downregulated, indicating the gene enhancing and repressing roles of Erβ-activated PrFs. In contrast, we detected a differential expression of only 824 genes in Erβnull follicles during PFGA (≥2-fold change; FDR p-value ≤ 0.05; TPM ≥ 5). Moreover, most (~93%; 770 out of 824) of these DEGs in activated Erβnull PrFs were downregulated. Such deregulation of genes in Erβnull activated follicles may impair their inhibitory role on PFGA. Notably, in both Erβnull PdFs and PrFs, we detected a significant number of epigenetic regulators and transcription factors to be differentially expressed, which suggests that lack of ERβ either directly or indirectly deregulates the gene expression in PdFs and PrFs, leading to increased PFGA.

The ERβ-cAMP signaling pathway regulates estradiol-induced ovine oocyte meiotic arrest

Although 17β-estradiol (E2) and its receptors (ERs) are reported to play important roles in regulating oocyte maturation, the specific mechanism remains unclear. First, we performed immunohistochemistry analyses to determine the expression of the ERα and ERβ proteins in ovine ovarian tissue. Second, E2 (0.5 ng/mL and 1 μg/mL) were added to pre-IVM medium for 0 h, 1 h and 2 h. The effects of E2 (0.5 ng/mL and 1 μg/mL) on cyclic adenosine monophosphate (cAMP) level in cumulus-oocyte complexes (COCs) and on oocyte meiotic progression were evaluated by ELISA and DAPI staining respectively. Third, the effects of E2 on the gene and protein expression of ERα and ERβ in COCs were investigated by Western blotting and real-time PCR. Afterward, ERβ and cAMP regulators were added to the 2-h pretreatment medium with or without E2 (0.5 ng/mL) to explore the possible interactions among E2, cAMP and ERβ. The results showed that both ERα and ERβ proteins were expressed in ovine cumulus layers and oocytes. E2 significantly increased intra-COC cAMP levels, maintained oocyte meiotic arrest, and promoted ERβ transcript and protein expression. E2 treatment increased the cAMP concentration, which was enhanced by ERβ agonist treatment and remarkably attenuated by ERβ inhibitor treatment. Forskolin plus IBMX treatment increased ERβ protein expression in COCs (P < 0.05), and this was attenuated by Rp-cAMP treatment. In conclusion, E2 (0.5 ng/mL) increased intra-COC cAMP levels by promoting ERβ expression, thereby maintaining oocyte meiotic arrest. cAMP in COCs has a positive feedback effect on ERβ expression, which provides a novel explanation for the positive role of E2 in regulating ovine follicle development and oocyte maturation.

Testosterone supplementation improves estrogen synthesis of buffalo (Bubalus bubalis) granulosa cells

Granulosa cells (GCs) synthesize estrogens needed for follicular growth. However, the effects of androgen on estrogen production in buffalo GCs remain unclear. In this study, the impacts of testosterone on estrogen synthesis in buffalo GCs were examined. The results showed that testosterone that was added to cell medium at a concentration of 10-7  mol/L and applied to GCs for 48 or 72 h enhanced the estrogen synthesis of buffalo GCs. This study provides a theoretical basis for further exploration of ovarian endocrine mechanism for steroidogenesis.

Histomorphological changes between short and long days in ovary guanacos (Lama guanicoe)

This is the first morpho-histological comparison of guanaco ovaries between reproductive (long-days) and non-reproductive (short-days) seasons, and oestrogen receptor-alpha (ERα) and beta (ERβ) detection. Different stages of follicle development were found in the cortical area, but no corpus luteum was detected. The size and frequency of antral follicles and large atretic follicles were higher in long-day ovaries than short-days, consistent with ovarian activity in this season. Differential expression of ERα and ERβ was observed in follicles at different stages of development between short and long days. These data reveal histological and molecular differences between reproductive and non-reproductive seasons of guanaco ovaries.

Single-cell profiling of mouse and primate ovaries identifies high levels of EGFR for stromal cells in ovarian aging

Increased ovarian fibrosis and an expanded stromal cell compartment are the main characteristics of aging ovaries. However, the molecular mechanisms and the key factor of stromal cells underlying ovarian aging remain unclear. Here, we explored single-cell transcriptomic data of ovaries from the adult mouse (4,363 cells), young (1,122 cells), and aged (1,479 cells) non-human primates (NHPs) to identify expression patterns of stromal cells between young and old ovaries. An increased number of stromal cells (p = 0.0386) was observed in aged ovaries of NHPs, with enrichment processes related to the collagen-containing extracellular matrix. In addition, differentially expressed genes of stromal cells between young and old ovaries were regulated by ESR1 (p = 7.94E-08) and AR (p = 1.99E-05). Among them, EGFR was identified as the common target and was highly expressed (p = 7.69E-39) in old ovaries. In human ovaries, the correlated genes of EGFR were associated with the process of the cell-substrate junction. Silencing of EGFR in human ovarian stromal cells led to the reduction of cell-substrate junction via regulating phosphorylation modification of the AKT-mTOR signaling pathway and stromal cell marker genes. Overall, we identified high levels of EGFR for stromal cells in ovarian aging, which provides insight into the cell type-specific molecular mechanisms underlying ovarian aging at single-cell resolution.

AOP key event relationship report: Linking decreased androgen receptor activation with decreased granulosa cell proliferation of gonadotropin-independent follicles

We recently proposed to formally recognize Key Event Relationships (KERs) as building blocks of Adverse Outcome Pathways (AOPs) that can be independently developed and peer-reviewed. Here, we follow this approach and provide an independent KER from AOP345, which describes androgen receptor (AR) antagonism leading to decreased female fertility. This KER connects AR antagonism to reduced granulosa cell proliferation of gonadotropin-independent follicles (KER2273). We have developed both the KER and the two adjacent Key Events (KEs). A systematic approach was used to ensure that all relevant supporting evidence for KER2273 was retrieved. Supporting evidence for the KER highlights the importance of AR action during the early stages of follicular development. Both biological plausibility and empirical evidence are presented, with the latter also assessed for quality. We believe that tackling isolated KERs instead of whole AOPs will accelerate the AOP development. Faster AOP development will lead to the development of simple test methods that will aid screening of chemicals, endocrine disruptor identification, risk assessment, and subsequent regulation.

Acetaminophen (APAP, Paracetamol) Interferes With the First Trimester Human Fetal Ovary Development in an Ex Vivo Model

CONTEXT

Acetaminophen (APAP, paracetamol) is widely used by pregnant women. Although long considered safe, growing evidence indicates that APAP is an endocrine disruptor since in utero exposure may be associated with a higher risk of male genital tract abnormalities. In rodents, fetal exposure has long-term effects on the reproductive function of female offspring. Human studies have also suggested harmful APAP exposure effects.

OBJECTIVE

Given that disruption of fetal ovarian development may impact women's reproductive health, we investigated the effects of APAP on fetal human ovaries in culture.

DESIGN AND SETTING

Human ovarian fragments from 284 fetuses aged 7 to 12 developmental weeks (DW) were cultivated ex vivo for 7 days in the presence of human-relevant concentrations of APAP (10-8 to 10-3 M) or vehicle control.

MAIN OUTCOME MEASURES

Outcomes included examination of postculture tissue morphology, cell viability, apoptosis, and quantification of hormones, APAP, and APAP metabolites in conditioned culture media.

RESULTS

APAP reduced the total cell number specifically in 10- to 12-DW ovaries, induced cell death, and decreased KI67-positive cell density independently of fetal age. APAP targeted subpopulations of germ cells and disrupted human fetal ovarian steroidogenesis, without affecting prostaglandin or inhibin B production. Human fetal ovaries were able to metabolize APAP.

CONCLUSIONS

Our data indicate that APAP can impact first trimester human fetal ovarian development, especially during a 10- to 12-DW window of heightened sensitivity. Overall, APAP behaves as an endocrine disruptor in the fetal human ovary.

Endoplasmic Reticulum Stress: A New Research Direction for Polycystic Ovary Syndrome?

Polycystic ovary syndrome (PCOS) is one of the most common gynecological endocrine disorders, with sporadic ovulation, excessive androgens, and polycystic ovarian changes as the main clinical manifestations. Due to the high heterogeneity of its clinical manifestations, the discussion on its pathogenesis has not been unified. Current research has found that genetic factors, hyperandrogenism, chronic inflammation and oxidative stress, insulin resistance, and obesity are strongly associated with PCOS. Recently, when studying the specific mechanisms of the abovementioned factors in PCOS, the biological response process of endoplasmic reticulum stress (ERS) has gradually come to researchers' attention, and several studies have confirmed the involvement of ERS in the pathogenesis of PCOS and the improvement of a series of pathological manifestations of PCOS after the application of ERS inhibitors, which may be a new entry point for the treatment of PCOS. In this article, we review the relationship between ERS and various pathogenic factors of PCOS.

Early preantral follicles of the domestic cat express gonadotropin and sex steroid signalling potential

Key biomolecular processes which regulate primordial ovarian follicle dormancy and early folliculogenesis in mammalian ovaries are not fully understood. The domestic cat is a useful model to study ovarian folliculogenesis and is the most relevant for developing in vitro growth methods to be implemented in wild felid conservation breeding programs. Previously, RNA-sequencing of primordial, primary, and secondary follicle samples from domestic cat implicated ovarian steroidogenesis and steroid reception during follicle development. Here we aimed to identify which sex steroid biosynthesis and metabolism enzymes, gonadotropin receptors, and sex steroid receptors are present and may be potential regulators. Differential gene expression, functional annotation, and enrichment analyses were employed and protein localisation was studied too. Gene transcripts for PGR, PGRMC1, AR (steroid receptors), CYP11A1, CYP17A1, HSD17B1 and HSD17B17 (steroidogenic enzymes), and STS (steroid metabolising enzyme) were significantly differentially expressed (Q values of ≤0.05). Differential gene expression increased in all transcripts during follicle transitions apart from AR which decreased by the secondary stage. Immunohistochemistry localised FSHR and LHCGR to oocytes at each stage. PGRMC1 immunostaining was strongest in granulosa cells whereas AR was strongest in oocytes throughout each stage. Protein signals for steroidogenic enzymes were only detectable in secondary follicles. Products of these significantly differentially expressed genes may regulate domestic cat preantral folliculogenesis. In vitro growth could be optimised as all early follicles express gonadotropin and steroid receptors meaning hormone interaction and response may be possible. Protein expression analyses of early secondary follicles supported its potential for producing sex steroids.

Dihydrotestosterone regulates oestrogen secretion, oestrogen receptor expression, and apoptosis in granulosa cells during antral follicle development

Dihydrotestosterone (DHT) is involved in the development of preantral follicles. However, the effect of DHT on the development of antral follicles has yet to be fully investigated. Herein, we used enzyme-linked immunosorbent assays, immunofluorescence assays, quantitative real time-polymerase chain reaction, immunohistochemical staining, and western blotting to investigate the effect of DHT on antral follicle development. First, we detected the concentration of DHT and the expression of the androgen receptor (AR) in different antral follicles. Second, multiple DHT concentration (10^-10-10^-7 M) were added to granulosa cells cultured in vitro to examine the influence of DHT on AR expression. Third, to study changes in the expression of oestrogen (E2) synthase and receptors during the development of antral follicles, we divided them according to their diameters into small (≤ 2 mm), medium (2-5 mm), and large (≥ 5 mm) groups. Fourth, we added DHT (10^-8 M) and flutamide (Flu, 10^-7 M) to granulosa cells to determine whether DHT regulates the expression of cytochrome P450 aromatase (CYP19A1) and the associated receptors through the AR pathway. Fifth, we tested the effect of DHT and Flu on the expression of apoptotic genes and proteins in granulosa cells. We found that AR was expressed in sheep antral follicle granulosa cells and was regulated by DHT. During antral follicle development, the concentration of E2 and the expression of CYP19A1 and E2 receptors significantly increased in granulosa cells. DHT influenced this increase, at least partially, through the AR. Moreover, DHT regulated the expression of apoptotic genes and proteins through the AR. Our study expands our knowledge on the regulatory mechanism of DHT in antral follicle development and guides further research on the androgen regulation of ovarian function.

Follicle-stimulating hormone and luteinizing hormone regulate the synthesis mechanism of dihydrotestosterone in sheep granulosa cells

Steroid hormones and receptors play important roles in female reproduction, and their expression patterns affect follicular growth and development. To examine the expression of dihydrotestosterone (DHT) synthases (5α-reductases (5α-red1 and 5α-red2)) and androgen receptor (AR) during follicular development, and the regulation of DHT signalling by follicle-stimulating hormone (FSH) and luteinizing hormone (LH), we have used enzyme-linked immunosorbent assays, quantitative real-time polymerase chain reaction, immunohistochemical staining and Western blotting to examine DHT synthesis in small (≤2 mm), medium (2-5 mm) and large (≥5 mm) sheep follicles. Expression of 5α-red1, 5α-red2 and AR was observed in ovine ovaries, and with the development of follicles, the expressions of 5α-red1 and 5α-red2 mRNA and protein increased, but the levels of AR mRNA, protein and DHT level decreased. In addition, granulosa cells were treated with FSH (0.01, 0.1 and 1 international unit (IU)/ml), LH (0.01, 0.1 and 1 IU/ml) and testosterone (T, 10^-7  M) to evaluate the effects of FSH and LH on DHT and oestradiol (E2) synthesis and 5α-red1, 5α-red2 and AR expression. We found that FSH and LH upregulated 5α-red1 and 5α-red2 in sheep granulosa cells, but downregulated the concentration of DHT and expression of AR. Meanwhile, FSH and LH significantly upregulated the expression of aromatase (P450arom) and secretion of E2. This result indicates that although FSH and LH promote the expression of 5α-red1 and 5α-red2, T is not transformed into DHT, but E2. This study reveals the reason why DHT concentration is downregulated in large follicles and lays a foundation for further exploring the synthesis mechanism of DHT during follicular development.

Exogenous Oestrogen Impacts Cell Fate Decision in the Developing Gonads: A Potential Cause of Declining Human Reproductive Health

The increasing incidence of testicular dysgenesis syndrome-related conditions and overall decline in human fertility has been linked to the prevalence of oestrogenic endocrine disrupting chemicals (EDCs) in the environment. Ectopic activation of oestrogen signalling by EDCs in the gonad can impact testis and ovary function and development. Oestrogen is the critical driver of ovarian differentiation in non-mammalian vertebrates, and in its absence a testis will form. In contrast, oestrogen is not required for mammalian ovarian differentiation, but it is essential for its maintenance, illustrating it is necessary for reinforcing ovarian fate. Interestingly, exposure of the bi-potential gonad to exogenous oestrogen can cause XY sex reversal in marsupials and this is mediated by the cytoplasmic retention of the testis-determining factor SOX9 (sex-determining region Y box transcription factor 9). Oestrogen can similarly suppress SOX9 and activate ovarian genes in both humans and mice, demonstrating it plays an essential role in all mammals in mediating gonad somatic cell fate. Here, we review the molecular control of gonad differentiation and explore the mechanisms through which exogenous oestrogen can influence somatic cell fate to disrupt gonad development and function. Understanding these mechanisms is essential for defining the effects of oestrogenic EDCs on the developing gonads and ultimately their impacts on human reproductive health.

Estrogen suppresses SOX9 and activates markers of female development in a human testis-derived cell line

Background

The increasing incidence of reproductive disorders in humans has been attributed to in utero exposure to estrogenic endocrine disruptors. In particular, exposure of the developing testis to exogenous estrogen can negatively impact male reproductive health. To determine how estrogens impact human gonad function, we treated the human testis-derived cell line NT2/D1 with estrogen and examined its impact on SOX9 and the expression of key markers of granulosa (ovarian) and Sertoli (testicular) cell development.

Results

Estrogen successfully activated its cognate receptor (estrogen receptor alpha; ESR1) in NT2/D1 cells. We observed a significant increase in cytoplasmic SOX9 following estrogen treatment. After 48 h of estrogen exposure, mRNA levels of the key Sertoli cell genes SOX9, SRY, AMH, FGF9 and PTGDS were significantly reduced. This was followed by a significant increase in mRNA levels for the key granulosa cell genes FOXL2 and WNT4 after 96 h of estrogen exposure.

Conclusions

These results are consistent with estrogen's effects on marsupial gonads and show that estrogen has a highly conserved impact on gonadal cell fate decisions that has existed in mammals for over 160 million years. This effect of estrogen presents as a potential mechanism contributing to the significant decrease in male fertility and reproductive health reported over recent decades. Given our widespread exposure to estrogenic endocrine disruptors, their effects on SOX9 and Sertoli cell determination could have considerable impact on the adult testis.

Therapeutic Effects and Mechanisms of Herbal Medicines for Treating Polycystic Ovary Syndrome: A Review

Background

Polycystic ovary syndrome (PCOS) is one of the most common disorders of endocrinology in reproductive-age women. In this study, we reviewed data on the effects and underlying mechanisms of herbal medicines used in the treatment of PCOS in laboratory studies.

Methods

Articles published in English up to June 30, 2018 were searched in Medline and EMBASE. We extracted data regarding herbal intervention; target cell (or animal model) usage; method of herbal extraction; route of administration; dosage and periods; and outcomes of the compounds isolated from herbs, individual herbal extracts, and herbal formula decoctions. We summarized the actions and the mechanisms underlying the beneficial effects of herbal medicines on PCOS.

Results

A total of 27 studies involving 22 herbal medicines reported their efficacy on PCOS. The herbal interventions in the 27 studies comprised four compounds isolated from herbs (6 studies), nine individual herbal extracts (11 studies), and nine herbal formula decoctions (10 studies). Herbal medicines normalized female hormones, diminished male hormones, recovered the estrous cycle, ameliorated insulin resistance, and improved lipid metabolism in PCOS. The mechanisms underlying the beneficial effects of herbal medicines on PCOS were found to be associated with anti-inflammation, anti-oxidative stress, inhibition of autophagy and/or apoptosis, and ovarian nerve growth factor reduction.

Conclusions

Herbal medicines are thought to be promising resources in the development of effective therapeutic agents for PCOS. Further studies that include methodological quality assessment and quantitative synthesis of outcomes are recommended.

Effects of Electroacupuncture on Ovarian Expression of the Androgen Receptor and Connexin 43 in Rats with Letrozole-Induced Polycystic Ovaries

Background

Polycystic ovarian syndrome (PCOS) occurs in women of reproductive age and is often characterized by reproductive and endocrine dysfunction. Androgens play a major role in PCOS, and previous studies reported abnormal expression of Connexin 43 (Cx43) in animal models of PCOS, suggesting an association of Cx43 with PCOS pathogenesis. Experimental and clinical evidence indicated that acupuncture may be a safe and effective approach for treating reproductive and endocrine disorders in women with PCOS. This study aimed to determine the effects of electroacupuncture (EA) on PCOS and its relationship with the expression of the androgen receptor (AR) and Cx43.

Methods

In total, 30 female Sprague Dawley rats (6 weeks old) were randomly divided into three groups: control group, letrozole (LE) group, and LE + EA group. Rats were administered LE solution (1.0 mg/kg) for 21 consecutive days to induce PCOS. For the LE + EA group, additional EA treatment was conducted (2 Hz, 20 min/d) with “Guanyuan” (CV3) for 14 consecutive days. After hematoxylin-eosin staining, the ovarian structure was observed with an optical microscope, and serum levels of the following hormones were examined via enzyme-linked immunosorbent assay (ELISA): testosterone (T), estradiol (E₂), sex hormone-binding globulin (SHBG), follicle-stimulating hormone (FSH); luteinizing hormone (LH), insulin (INS), anti-Müllerian hormone (AMH), and inhibin B (INHB). Fasting blood glucose (FBG) levels were evaluated using glucose oxidase-peroxidase. Ovarian mRNA and protein expressions of AR and Cx43 were determined by real-time RT-PCR and Western blot analysis.

Results

EA was found to restore the cyclicity and ovarian morphology in the PCOS rat model. Serum derived from the LE + EA group showed significant decreases in the levels of T, free androgen index (FAI), LH, LH/FSH ratio, AMH, INHB, and fasting serum insulin (FINS), and significant increases in the levels of E₂, FSH, and SHBG. Western blot analysis showed a decreased protein expression of ovarian AR and Cx43; real-time RT-PCR showed reduced expression of ovarian mRNA levels of AR and Cx43.

Conclusions

In conclusion, our results showed that EA can ease hyperandrogenism and polycystic ovary morphology in PCOS rats. Furthermore, EA counteracted the letrozole-induced upregulation of AR and Cx43. These results suggested that acupuncture can break the vicious cycle initiated by excessive androgen secretion and may be an effective treatment method for improving the reproductive and endocrine dysfunction caused by PCOS.

Pre-Implantation Effects of Progesterone Administration on Ovarian Angiogenesis after Ovarian Stimulation: A Histological, Hormonal, and Molecular Analysis

OBJECTIVE

Progesterone (P4) is known to directly affect ovarian tissue angiogenesis. The present study was designed to show how P4 affects ovarian angiogenesis in hormonal, histological, and molecular levels.

METHODS

Fifteen adult female NMRI mice were divided into three groups: Control Group; Case Group I (ovarian stimulation alone); and Case Group II (ovarian stimulation followed by P4 administration). Blood and ovarian tissue samples were assessed for hormonal, histological, and molecular alterations. Gene expression for ovarian vascular endothelium growth factor (VEGF) and hypoxia-inducible factor-1 alpha (HIF-1α) was analyzed using real-time PCR.

RESULTS

Ovarian hormone levels were increased in the case groups compared with the control group (p<0.05). Quantitative corpus luteum parameters were increased in the case groups compared with the control group (p<0.05). Quantitative ovarian vascular parameters were significantly different in the case groups compared with the control group. Gene expression analyses shows that the mice in Case Group I had higher levels of ovarian VEGF expression than the mice in the control group (p<0.05). No significant difference in gene expression was observed for HIF-1ɑ.

CONCLUSION

Treatment with P4 after ovarian stimulation enhanced ovarian angiogenesis by increasing hormone levels and causing significant structural changes.

Prenatal programming by testosterone of follicular theca cell functions in ovary

In mammalian ovaries, the theca layers of growing follicles are critical for maintaining their structural integrity and supporting androgen synthesis. Through combining the postnatal monitoring of ovaries by abdominal magnetic resonance imaging, endocrine profiling, hormonal analysis of the follicular fluid of growing follicles, and transcriptomic analysis of follicular theca cells, we provide evidence that the exposure of ovine fetuses to testosterone excess activates postnatal follicular growth and strongly affects the functions of follicular theca in adulthood. Prenatal exposure to testosterone impaired androgen synthesis in the small antral follicles of adults and affected the expression in their theca cells of a wide array of genes encoding extracellular matrix components, their membrane receptors, and signaling pathways. Most expression changes were uncorrelated with the concentrations of gonadotropins, steroids, and anti-Müllerian hormone in the recent hormonal environment of theca cells, suggesting that these changes rather result from the long-term developmental effects of testosterone on theca cell precursors in fetal ovaries. Disruptions of the extracellular matrix structure and signaling in the follicular theca and ovarian cortex can explain the acceleration of follicle growth through altering the stiffness of ovarian tissue. We propose that these mechanisms participate in the etiology of the polycystic ovarian syndrome, a major reproductive pathology in woman.

Undernutrition and hyperandrogenism during pregnancy: Role in programming of cardiovascular disease and infertility

Maternal nutritional status programs the development of several systems in female offspring, with effects that depend on the severity, duration, and window of development when the nutritional perturbation is imposed. On the basis of the developmental origins of health and disease concept, we hypothesize that gestational low caloric intake may induce maternal subclinical hyperandrogenism during early pregnancy and compromise cardiovascular health and fertility in the female offspring. To examine this possibility, a literature search for human and animal studies was conducted using two electronic databases, PubMed and Cochrane until April 2019 to address the following questions: (a) Do androgens have a developmental role in cardiovascular and ovarian development? (b) Is excess maternal testosterone linked to cardiovascular disease and infertility? and (c) Could early pregnancy undernutrition enhance maternal androgen production and compromise health and fertility in female offspring? The observations reviewed, establish a potential causative link between maternal undernutrition and subclinical hyperandrogenism with hypertension and reduced ovarian reserve in the progeny. Further studies in appropriate models are needed to better understand whether low energy intake and subclinical maternal hyperandrogenism during early pregnancy can negatively affect the health of the female offspring.

MiR-26a promotes apoptosis of porcine granulosa cells by targeting the 3β-hydroxysteroid-Δ24-reductase gene

Objective

Apoptosis of ovarian granulosa cells (GCs) affects mammalian follicular development and fecundity. This study aimed to explore the regulatory relationship between microRNA-26a (miR-26a) and the 3β-hydroxysteroid-Δ24-reductase gene (DHCR24) gene in porcine follicular granular cells (pGCs), and to provide empirical data for the development of methods to improve the reproductive capacity of pigs.

Methods

The pGCs were transfected with miR-26a mimic, miR-26a inhibitor and DHCR24-siRNA in vitro. The cell apoptosis rate of pGCs was detected by the flow cytometry. The secretion levels of estradiol (E2) and progesterone (P) in pGCs were detected by enzyme-linked immunosorbent assay. Double luciferase validation system was used to detect the binding sites between miR-26a and DHCR24 3′-UTR region. Qualitative real-time polymerase chain reaction and Western blotting were used to verify the DHCR24 mRNA and protein expression in pGCs, respectively, after transfecting with miR-26a mimic and miR-26a inhibitor.

Results

Results showed that enhancement of miR-26a promoted apoptosis, and inhibited E2 and P secretion in pGCs. Meanwhile, inhibition of DHCR24 also upregulated the Caspase-3 expression, reduced the BCL-2 expression, promoted pGCs apoptosis, and inhibited E2 and P secretion in pGCs. There were the binding sites of miR-26a located within DHCR24 3′-UTR. Up-regulation of miR-26a inhibited DHCR24 mRNA and protein expression in pGCs.

Conclusion

This study demonstrates that miR-26a can promote cell apoptosis and inhibit E2 and P secretion by inhibiting the expression of DHCR24 in pGCs.

MiR-222 inhibits apoptosis in porcine follicular granulosa cells by targeting the THBS1 gene

Apoptosis of granulosa cells affects follicular atresia and reproduction and is regulated by miRNAs and the expression of certain genes. For the present study, we investigated the regulatory relationship between microRNA-222 (miR-222) and THBS1 in porcine follicular granulosa cells (pGCs) and its effects on apoptosis to provide empirical data for developing methods to improve pig fecundity. Results revealed that miR-222 promotes the proliferation of pGCs. MiRNA mimics and luciferase reporter assays revealed that miR-222 functions as an anti-apoptotic factor in pGCs. MiR-222 mimics in pGCs result in the upregulation of the anti-apoptotic BCL-2 gene, down-regulation of the proapoptotic caspase-3 gene, and inhibition of apoptosis. MiR-222 inhibitors reduced BCL-2 and had no significant effect on caspase-3. MiR-222 mimics promoted estrogen levels. Inhibition of THBS1 inhibited pGC apoptosis. Transfection of THBS1-siRNA reduced the proapoptotic BAX gene. MiR-222 can directly target the 3'-untranslated region of the THBS1 gene. MiR-222 mimics suppressed THBS1 mRNA and proteins, but these were upregulated by the miR-222 inhibitor. Transfection of THBS1-siRNA resulted in the inhibition of the miR-222 inhibitor, which suggests that miR-222 inhibits pGC apoptosis by targeting THBS1. These findings suggest that miR-222 and THBS1 play important roles in follicular atresia, ovarian development, and female reproduction.

Dehydroepiandrosterone Supplementation Improves the Outcomes of in vitro Fertilization Cycles in Older Patients With Diminished Ovarian Reserve

Background: Dehydroepiandrosterone (DHEA) supplementation has been reported to have beneficial effects on the in vitro fertilization (IVF) outcomes of patients with poor ovarian response or diminished ovarian reserve. The Patient-Oriented Strategies Encompassing IndividualizeD Oocyte Number (POSEIDON) stratification is a set of newly established criteria for low prognosis patients. The aim of this study was to examine the potential effects of DHEA supplementation on the IVF outcomes of patients who fulfill the POSEIDON group 4 criteria. Methods: This retrospective cohort study investigated 297 cycles that fulfilled the POSEIDON group 4 criteria and underwent IVF treatment using the gonadotropin-releasing hormone antagonist protocol. The study group contained 159 cycles that received DHEA (30 mg three times per day) daily for 12 weeks before their IVF cycles. The control group included 138 cycles that underwent IVF cycles but did not receive DHEA. The baseline characteristics and cycle parameters as well as the IVF outcomes of both groups were compared. Results: In terms of baseline characteristics, more previous IVF attempts and lower AMH levels were found in the study group than in the control group. Regarding IVF outcomes, patients in the study group had significantly higher follicular oocyte index and higher numbers of retrieved oocytes, metaphase II oocytes, fertilized oocytes, day 3 embryos and top-quality day 3 embryos than those in the control group. Besides, a higher cumulative pregnancy rate and lower cancellation rate were observed in the study group than in the control group although clinical pregnancy rate, live birth rate, and cumulative live birth rate did not differ between the two groups. Whether patients are aged ≤ 40 years or aged > 40, higher numbers of oocytes and embryos were observed in the study group than in the control group. In patients aged > 40, cumulative pregnancy rate was significantly higher in the study group than in the control group. Conclusions: Our data suggest that DHEA supplementation might increase both oocyte and embryo yields, as well as cumulative pregnancy rates, in patients fulfilling the POSEIDON group 4 criteria.

First ovarian response to gonadotrophin stimulation in rats exposed to neonatal androgen excess

This study analyzes the effects of neonatal androgenization on follicular growth and first ovulation in response to gonadotrophins, using a model of exogenous stimulation or the use of subcutaneous ovary grafts in castrated animals to replace the hypothalamus-pituitary signal. Neonatal rats (days 1-5) were treated with testosterone, dihydrotestosterone or vehicle. At juvenile period, rats were stimulated with PMSG, hCG (alone or combined) or used as ovarian donors to be grafted on castrated adult female rats. Ovulation and ovarian histology were analyzed in both groups. Animals treated with vehicle or dihydrotestosterone stimulated with gonadotrophins (pharmacological or by using an ovary graft) ovulated, showing a normal histological morphology whereas rats exposed to testosterone and injected with the same doses of gonadotrophins did not it. In this group, ovulation was reached using a higher dose of hCG. Ovaries in the testosterone group were characterized by the presence of follicles with atretic appearance and a larger size than those observed in control or dihydrotestosterone groups. A similar appearance was observed in testosterone ovary grafts although luteinization and some corpora lutea were also identified. Our findings suggest that neonatal exposure to aromatizable androgens induces a more drastic signalling on the ovarian tissue that those driven by non-aromatizable androgens in response to gonadotrophins.

The local regulation of folliculogenesis by members of the transforming growth factor superfamily and its relevance for advanced breeding programmes

Regulation of the growth and maturation of the ovarian follicle is critical for normal reproductive function. Alterations in this growth can lead to pathological conditions, such as cystic follicles, reduced oocyte quality, or an abnormal endocrine environment leading to poor fertility. Alterations in follicular growth also influence the number of follicles ovulating and thus can change litter size. Both endocrine factors, such as follicle stimulating hormone and luteinizing hormone, as well as local factors, are known to regulate follicular growth and development. This review will focus on the role of local factors in regulation of ovarian follicular growth in ruminants, with a focus on members of the transforming growth factor superfamily. The potential role of these factors in regulating proliferation, apoptosis, steroidogenesis and responsiveness to gonadotrophins will be considered.

Intrafollicular level of steroid hormones and the expression of androgen receptor in the equine ovary at puberty

Steroidogenic activity in the equine ovary from birth to puberty has been poorly investigated. This study aimed to examine the capability of the ovarian follicles of prepubertal and pubertal fillies to produce steroid hormones and to evaluate the expression and cellular localization of androgen receptor (AR) in their ovaries. The ovaries of 6-18 month-old fillies were divided into two groups: prepubertal (PrP) - without preovulatory follicle (pF) and corpus luteum (CL), and ovulating/postpubertal (Ov/pB) - with pF and/or CL in at least one of the gonads. Adult mares (Me) were used as a control. The concentration of progesterone (P4), testosterone (T) and estradiol (E2) in follicular fluid (FF) was measured by radioimmunoassay. AR distribution was assessed by immunohistochemistry, while AR protein expression was examined by Western blot analysis. In the female groups, E2 concentration in FF of small follicles (<10 mm) was low and increased with the diameter of the follicle reaching the greatest value in pF (Ov/pB and Me group). In follicles (11-30 mm) of PrP fillies, the concentration of E2 was similar to that from Ov/pB fillies, but less than half (P < 0.05) than in Me follicles. In FF from all classes of follicles of Ov/pB fillies, the concentration of all steroids was similar to that in Me. AR immunolocalization, predominantly nuclear, was observed in all types of follicular cells (granulosa and theca cells) as well as in stroma and luteal cells. The pattern of staining was dependent on the follicle size and the group of females. In smaller antral follicles and in pF, the nuclear AR staining in granulosa cells was stronger than that found in follicles of 21-25 mm. In theca interna cells of pF, both nuclear and faint cytoplasmic reactions were seen. In luteal cells, AR labeling was noted in the nuclei and the cytoplasm: the strongest one in the early CL and almost negative in the late CL. AR protein expression in filly and mare ovarian tissues was confirmed by Western blot analysis and detected as a single band at approximately 110 kDa. In summary, the ovaries of fillies aged at least 6 months are capable of active steroidogenesis. ARs are present either in the cell nuclei or cytoplasm of all compartments of the equine ovary. AR expression in follicular and stroma cells may indicate the sensitivity of the filly ovarian tissue to androgens, the impact of androgens on folliculogenesis and the development of the equine ovary via a receptor-mediated pathway.

Role of androgens in the ovary

It has been well established for decades that androgens, namely testosterone (T) plays an important role in female reproductive physiology as the precursor for oestradiol (E₂). However, in the last decade a direct role for androgens, acting via the androgen receptor (AR), in female reproductive function has been confirmed. Deciphering the specific roles of androgens in ovarian function has been hindered as complete androgen resistant females cannot be generated by natural breeding. In addition, androgens can be converted into estrogens which has caused confusion when interpreting findings from pharmacological studies, as observed effects could have been mediated via the AR or estrogen receptor. The creation and analysis of genetic mouse models with global and cell-specific disruption of the Ar gene, the sole mediator of pure androgenic action, has now allowed the elucidation of a role for AR-mediated androgen actions in the regulation of normal and pathological ovarian function. This review aims to summarize findings from clinical, animal, pharmacological and novel genetic AR mouse models to provide an understanding of the important roles androgens play in the ovary, as well as providing insights into the human implications of these roles.

Androgen Action in the Ovary

Androgen production by the ovary is an essential requirement for normal cyclical secretion of estradiol but its physiological role extends to important actions on both preantral and antral follicle development, including promotion of granulosa cell proliferation. It is likely only in mature antral follicles that androgens encourage apoptosis and consequent follicle atresia, and this may be an important mechanism to ensure mono-follicular ovulation in primates, including humans. Recent studies have provided new insight into the mechanism of androgen signaling in the ovary which involves both genomic and non-genomic effects that are complementary in effecting a cellular response. In polycystic ovary syndrome, a condition characterized by intra-ovarian androgen excess, aberrant development of both preantral and antral follicles is a salient feature. We present evidence that local action of androgens plays a part in such abnormalities. Finally, we review the role of androgens in follicle atresia and conclude that the effects are part of the normal physiology of follicle maturation.

Xiao-Yao-San, a Chinese Medicine Formula, Ameliorates Chronic Unpredictable Mild Stress Induced Polycystic Ovary in Rat

Chronic stress induces endocrine disturbance, which contributes to the development of polycystic ovary syndrome (PCOS), a condition that remains a challenge for clinicians to cope with. The present study investigated the effect of Xiao-Yao-San (XYS), a traditional Chinese medicine formula used for treatment of gynecological disease, on the chronic stress-induced polycystic ovary and its underlying mechanism. Female Sprague-Dwaley rats underwent a 3 weeks chronic unpredictable mild stress (CUMS) procedure to establish the PCOS model, followed by 4 weeks treatment with XYS (0.505 g/kg or 1.01 g/kg) by gavage. Granulosa cells were exposed to noradrenaline (1 mM) in vitro for 24 h, followed by incubation with or without XYS-treated rat serum for 24 h. Post-treatment with XYS ameliorated CUMS-induced irregular estrous cycles and follicles development abnormalities, decrease of estradiol and progesterone level as well as increase of luteinizing hormone in serum, reduced cystic follicles formation and the apoptosis and autophagy of granulosa cells, attenuated the increase in dopamine beta hydroxylase and c-fos level in locus coeruleus, the noradrenaline level in serum and ovarian tissue, and the expression of beta 2 adrenergic receptor in ovarian tissue. Besides, XYS alleviated the reduction of phosphorylation of ribosomal protein S6 kinase polypeptide I and protein kinase B, as well as the increase of microtubule-associated protein light chain 3-I to microtubule-associated protein light chain 3-II conversion both in vivo and in vitro. This study demonstrated XYS as a potential strategy for CUMS induced polycystic ovary, and suggested that the beneficial role of XYS was correlated with the regulation of the sympathetic nerve activity.

Is progesterone the key regulatory factor behind ovulation rate in sheep?

Ovarian antral follicles in the ewe grow in an orderly succession, producing 3 to 4 waves per estrous cycle. In prolific sheep, some large antral follicles from the second-to-last wave of the estrous cycle are added to the ovulatory follicles emerging just before estrus to give a higher ovulation rate; it is feasible that regression of these follicles is prevented by an increase in serum concentrations of FSH or LH pulsatility at proestrus. Prolific sheep tend to have a shorter luteal phase than nonprolific ewes and there is a great deal of evidence that luteal progesterone (P₄), in addition to regulating LH release, may govern the secretion of FSH heralding the emergence of follicular waves. The specific purpose of this study was to determine whether or not extending the duration of the luteal phase in prolific sheep to that typically seen in nonprolific breeds would alter the follicle wave dynamics and ovulation rate. In 2 separate experiments, exogenous P₄ (7.5 mg per ewe intramuscularly) was administered on day 11 at PM and day 12 at AM (day 0 = first ovulation of the interovulatory interval studied) in moderately prolific Rideau Arcott × Polled Dorset ewes (experiment 1, n = 8) and highly prolific Olkuska ewes (experiment 2, n = 7; TRT), whereas the equinumerous groups of animals served as controls (CTR). Transrectal ovarian ultrasonography was performed daily, and jugular blood samples were drawn twice a day from day 9 until the next ovulation. Progesterone injections resulted in relatively uniform increments in serum P₄ levels, but the mean duration of the interovulatory interval did not differ (P > 0.05) between TRT and CTR groups of ewes in either experiment. The mean ovulation rate post-treatment was 1.6 ± 0.2 vs 3.2 ± 0.4 (experiment 1, P < 0.001) and 3.2 ± 0.8 vs 4.0 ± 1.0 (experiment 2, P > 0.05) in TRT vs CTR, respectively. The number and percentage of ovulating follicles from the penultimate wave of the interovulatory interval studied was 0.25 ± 0.16 vs 1.75 ± 0.45 (P < 0.01) and 25.0 ± 16.4% vs 75.0 ± 16.4% (P < 0.05) in experiment 1, and 0.50 ± 0.30 vs 1.60 ± 0.40 (P < 0.05) and 13.8 ± 9.0% vs 53.4 ± 16.7% (P < 0.05) in experiment 2, for TRT vs CTR, respectively. In summary, administration of P₄ at the end of diestrus decreased the incidence of ovulations from the penultimate wave of the estrous cycle in both the moderately and highly prolific strains of sheep, but it reduced the ovulation rate only in moderately prolific ewes.

Activity of Zearalenone in the Porcine Intestinal Tract

This study demonstrates that low doses (somewhat above the No Observed Adverse Effect Level, NOAEL) of the mycoestrogen zearalenone (ZEN) and its metabolites display multispecificity towards various biological targets in gilts. The observed responses in gilts were surprising. The presence of ZEN and zearalenols (ZELs) did not evoke a response in the porcine gastrointestinal tract, which was attributed to dietary tolerance. Lymphocyte proliferation was intensified in jejunal mesenteric lymph nodes, and lymphocyte counts increased in the jejunal epithelium with time of exposure. In the distal digestive tract, fecal bacterial counts decreased, the activity of fecal bacterial enzymes and lactic acid bacteria increased, and cecal water was characterized by higher genotoxicity. The accompanying hyperestrogenism led to changes in mRNA activity of selected enzymes (cytochrome P450, hydroxysteroid dehydrogenases, nitric oxide synthases) and receptors (estrogen and progesterone receptors), and it stimulated post-translational modifications which play an important role in non-genomic mechanisms of signal transmission. Hyperestrogenism influences the regulation of the host's steroid hormones (estron, estradiol and progesteron), it affects the virulence of bacterial genes encoding bacterial hydroxysteroid dehydrogenases (HSDs), and it participates in detoxification processes by slowing down intestinal activity, provoking energy deficits and promoting antiporter activity at the level of enterocytes. In most cases, hyperestrogenism fulfils all of the above roles. The results of this study indicate that low doses of ZEN alleviate inflammatory processes in the digestive system, in particular in the proximal and distal intestinal tract, and increase body weight gains in gilts.

Effect of testosterone on the Connexin37 of sexual mature mouse cumulus oocyte complex

BACKGROUND

Recent researches demonstrate that pre-treatment with androgen could increase retrieved oocytes number and clinical pregnancy rate in poor ovarian response (POR) patients. In view of gap junction intercellular communication (GJIC) is important for follicular growth, and androgen plays an important role in improving prognosis of POR patients, we speculate that androgen can increase the expression of connexin in follicle cells, and improve ovarian microenvironment, thus can promote ovarian response. The objective of the research is to study the effect of testosterone on connexin37 (Cx37) expression so as to provide theoretical basis for adding testosterone in treatment of POR.

METHODS

Cumulus-oocyte-cells (COCs) were collected from ICR mice ovaries, and were cultured in vitro for 48 h and then treated with testosterone (T) at various concentration. To assess whether the effect of androgen on Cx37 expression is mediated through androgen receptor (AR) pathway, COCs were cultured in vitro with Flutamide (androgen receptor antagonist). The expression of Cx37 was determined by western blot.

RESULTS

The expression of Cx37 in COCs which were treated with testosterone was higher than that of control group. There were significant differences (P < 0.001;<0.001;<0.001;<0.001). Cx37 increased with the elevated testosterone concentrations. Cx37 was lower in androgen receptor antagonist group (2.57 ± 0.12) than the corresponding testosterone concentrations group (4.42 ± 0.28). There were significant differences between two groups (P < 0.001).

CONCLUSIONS

There was close relationship between gap junction protein and ovarian response, which suggested that androgen could promote ovarian response by increasing the expression of Cx37 in follicle. Androgen plays an important role in ovarian response through the AR pathway and non-AR pathway.

Immunohistochemical localization of androgen receptors in female mole rat (Spalax leucodon) tissues

Androgens exert their effects through androgen receptors (AR) in tissues. We investigated the distribution of AR in female mole rat tissues. Tissues were excised, fixed with 10% formalin and embedded in paraffin. Sections were stained after microwave antigen retrieval for immunohistochemistry. Immunostaining of AR immunostaining was detected in the nucleus or cytoplasm of the cells in the cerebral cortex, cerebellum, anterior pituitary, lung, liver, uterus and skin. Granulosa and some thecal cells in the ovary, cardiac muscle cells and adipose cells exhibited a nuclear reaction for AR. In the kidney, labeling of AR was restricted to the cytoplasm of tubule cells. We found that AR could be detected using immunohistochemistry in the nucleus or cytoplasm or both in the presence of androgens.

Long-term storage does not impact the quality of cryopreserved human ovarian tissue

Background

Ovarian tissue cryopreservation is an emerging technique, also addressed to very young cancer patients, for whom it is not possible to perform an ovarian stimulation for oocytes freezing, before gonadotoxic treatment. In this cases, ovarian tissue must be cryopreserved for a long period of time and it is very important to know if it maintains fertility function after a long period of storage. Here we aimed to assess the effect of long-term storage on preservation and viability of cryopreserved human ovarian tissue.

Methods

Descriptive study of three cases of cancer patients whose cryopreserved ovarian tissue remained stored for 18 years. Long-term stored tissue was examined by histological and immunohistochemical analysis, transmission electron microscopy, TUNEL assay and LIVE/DEAD viability/citotoxicity test.

Results

Ovarian tissue stored for 18 years showed a good morphology. Follicles presented negative staining for estrogen and progesterone receptors, positive staining for ki67 in granulosa cells and/or oocytes and for bcl2 in granulosa cells. Regarding stroma, patch/focal positive expression was found for estrogen receptor and ki67, diffusely positive expression for progesterone receptor and bcl2. After long-term storage, ultrastructural examination showed sub-cellular integrity of follicles and interstitial oedema foci. No apoptosis was observable by TUNEL assay. Stromal cell viability remained >97 % during the culture period.

Conclusion

The evaluation of different aspects of the tissue provides evidence that the storage time does not impact on tissue quality and gives hope especially to cancer girls, whose tissues could remain cryopreserved for a very long time.

Early embryo loss, morphology, and effect of previous immunization against androstenedione in the ewe

In a naturally mated cycle, ova and viable embryo number as well as embryo size were assessed on Day 4, 10, 14, 18, and 30 of gestation in Romney ewes (n = 38-44 per gestational group). For Days 4-18 of gestation, embryos were recovered by flushing the reproductive tract after slaughtering of the ewe. Ovulation rate was determined by counting the number of corpora lutea present on both ovaries. For the Day 30 group, number of ovulations was measured by laparoscopic examination of the ovaries at Day 9-12 of the cycle, and number of embryos present was determined by ultrasound examination at approximately Day 30 of pregnancy. Most of embryo loss occurred before Day 14 of gestation with 6% loss before Day 4, and 12% loss between Day 4 and 14 of gestation. A similar proportion of viable embryos per number of ova ovulated were recovered on Day 14 and 18 (82%) and Day 30 (81%) of gestation. Fertilization failure was estimated at 1%. Conceptus and embryo size was most variable on Day 14, representing a period of rapid growth (conceptus length ± standard deviation); Day 4 (169 ± 8 μm), Day 10 (379 ± 93 μm), Day 14 (23 ± 32 mm), Day 18 (embryo length ± standard deviation; 5.0 ± 0.7 mm). Vaccination with commercially available fertility vaccines targeting androstenedione (Androvax and Ovastim) in previous seasons resulted in reduced conceptus size compared with controls. However, no difference in the proportion of viable embryos was observed between treatments, signifying maternal tolerance for considerable variation at this stage of development. Furthermore, the finding that most of loss occurs within the first 14 days of gestation highlights the importance of both oocyte quality and the uterine environment for the embryo to successfully overcome the challenges leading up to and including pregnancy recognition in the ewe.

Generation of an estrogen receptor beta-iCre knock-in mouse

A novel knock-in mouse that expresses codon-improved Cre recombinase (iCre) under regulation of the estrogen receptor beta (Esr2) promoter was developed for conditional deletion of genes and for the spatial and/or temporal localization of Esr2 expression. ESR2 is one of two classical nuclear estrogen receptors and displays a spatiotemporal expression pattern and functions that are different from the other estrogen receptor, ESR1. A cassette was constructed that contained iCre, a polyadenylation sequence, and a neomycin selection marker. This construct was used to insert iCre in front of the endogenous start codon of the Esr2 gene of a C57BL/6J embryonic stem cell line via homologous recombination. Resulting Esr2-iCre mice were bred with ROSA26-lacZ and Ai9-RFP reporter mice to visualize cells of functional iCre expression. Strong expression was observed in the ovary, the pituitary, the interstitium of the testes, the head and tail but not body of the epididymis, skeletal muscle, the coagulation gland (anterior prostate), the lung, and the preputial gland. Additional diffuse or patchy expression was observed in the cerebrum, the hypothalamus, the heart, the adrenal gland, the colon, the bladder, and the pads of the paws. Overall, Esr2-iCre mice will serve as a novel line for conditionally ablating genes in Esr2-expressing tissues, identifying novel Esr2-expressing cells, and differentiating the functions of ESR2 and ESR1.

Localisation and endocrine control of hyaluronan synthase (HAS) 2, HAS3 and CD44 expression in sheep granulosa cells

The aim of the present study was to investigate the hormonal regulation of hyaluronan (HA) components in sheep granulosa cells. HA components are present in the reproductive tract and have a range of physical and signalling properties related to reproductive function in several species. First, abattoir-derived ovaries of sheep were used to determine the localisation of HA synthase (HAS) 1–3 and CD44 proteins in antral follicles. Staining for HAS1–3 and CD44 proteins was most intense in the granulosa layer. Accordingly, the expression of HAS2, HAS3 and CD44 mRNA was measured in cultured granulosa cells exposed to 0–50 ng mL–1 of 17β-oestradiol and different combinations of oestradiol, gonadotropins, insulin-like growth factor (IGF)-1 and insulin for 48–96 h (1 ng mL–1 FSH, 10 ng mL–1 insulin, 10 ng mL–1 IGF-1, 40 ng mL–1 E2 and 25 ng mL–1 LH.). mRNA expression was quantified by real-time polymerase chain reaction using a fold induction method. The results revealed that the hormones tested generally stimulated mRNA expression of the genes of interest in cultured granulosa cells. Specifically, oestradiol, when combined with IGF-1, insulin and FSH, stimulated HAS2 mRNA expression. Oestradiol and LH had synergistic effects in increasing HAS3 mRNA expression. In conclusion, we suggest that the hormones studied differentially regulate HAS2, HAS3 and CD44 in ovine granulosa cells in vitro. Further work is needed to address the signalling pathways involved.

Zearalenone in the Intestinal Tissues of Immature Gilts Exposed per os to Mycotoxins

Zearalenone and its metabolites, α-zearalenol and β-zearalenol, demonstrate estradiol-like activity and disrupt physiological functions in animals. This article evaluates the carryover of zearalenone and its selected metabolites from the digesta to intestinal walls (along the entire intestines) in pre-pubertal gilts exposed to low doses of zearalenone over long periods of time. The term “carryover” describes the transfer of mycotoxins from feed to edible tissues, and it was used to assess the risk of mycotoxin exposure for consumers. The experimental gilts with body weight of up to 25 kg were per os administered zearalenone at a daily dose of 40 μg/kg BW (Group E, n = 18) or placebo (Group C, n = 21) over a period of 42 days. In the first weeks of exposure, the highest values of the carryover factor were noted in the duodenum and the jejunum. In animals receiving pure zearalenone, the presence of metabolites was not determined in intestinal tissues. In the last three weeks of the experiment, very high values of the carryover factor were observed in the duodenum and the descending colon. The results of the study indicate that in animals exposed to subclinical doses of zearalenone, the carryover factor could be determined by the distribution and expression of estrogen receptor beta.

Caloric restriction increases ratio of estrogen to androgen receptors expression in murine ovaries--potential therapeutic implications

Both estrogens and androgens are involved in the development and normal functioning of the ovaries. It is also known that ovarian function is regulated by diet. The goal of this study was to estimate the expression of sex hormone receptors in ovaries of mice that were on a 9-month caloric restriction (alternate-day feeding) as compared to normal control animals fed ad libitum. We found that prolonged caloric restriction in mouse ovaries led to increased expression of estrogen receptors (ERs) but did not affect expression of the androgen receptor (AR). This increase in ER:AR ration as result of caloric restriction may lead to higher sensitivity to estrogens and upon return to normal diet may increase ovulation. Thus our observation shed more light on a role of beneficial effect of calorie restriction on female reproduction.

Role of androgens in normal and pathological ovarian function

Androgens mediate their actions via the androgen receptor (AR), a member of the nuclear receptor superfamily. AR-mediated androgen action is essential in male reproductive development and function; however, only in the last decade has the suspected but unproven role for AR-mediated actions in female reproduction been firmly established. Deciphering the specific roles and precise pathways by which AR-mediated actions regulate ovarian function has been hindered by confusion on how to interpret results from pharmacological studies using androgens that can be converted into oestrogens, which exert actions via the oestrogen receptors. The generation and analysis of global and cell-specific femaleArknockout mouse models have deduced a role for AR-mediated actions in regulating ovarian function, maintaining female fertility, and have begun to unravel the mechanisms by which AR-mediated androgen actions regulate follicle health, development and ovulation. Furthermore, observational findings from human studies and animal models provide substantial evidence to support a role for AR-mediated effects not only in normal ovarian function but also in the development of the frequent ovarian pathological disorder, polycystic ovarian syndrome (PCOS). This review focuses on combining the findings from observational studies in humans, pharmacological studies and animal models to reveal the roles of AR-mediated actions in normal and pathological ovarian function. Together these findings will enable us to begin understanding the important roles of AR actions in the regulation of female fertility and ovarian ageing, as well as providing insights into the role of AR actions in the androgen-associated reproductive disorder PCOS.

Neonatal exposure to xenoestrogens impairs the ovarian response to gonadotropin treatment in lambs

Bisphenol A (BPA) and diethylstilbestrol (DES) are xenoestrogens, which have been associated with altered effects on reproduction. We hypothesized that neonatal xenoestrogen exposure affects the ovarian functionality in lambs. Thus, we evaluated the ovarian response to exogenous ovine FSH (oFSH) administered from postnatal day 30 (PND30) to PND32 in female lambs previously exposed to low doses of DES or BPA (BPA50: 50 μg/kg per day, BPA0.5: 0.5 μg/kg per day) from PND1 to PND14. We determined: i) follicular growth, ii) circulating levels of 17β-estradiol (E2), iii) steroid receptors (estrogen receptor alpha, estrogen receptor beta, and androgen receptor (AR)) and atresia, and iv) mRNA expression levels of the ovarian bone morphogenetic protein (BMPs) system (BMP6, BMP15, BMPR1B, and GDF9) and FSH receptor (FSHR). Lambs neonatally exposed to DES or BPA showed an impaired ovarian response to oFSH with a lower number of follicles ≥2 mm in diameter together with a lower number of atretic follicles and no increase in E2 serum levels in response to oFSH treatment. In addition, AR induction by oFSH was disrupted in granulosa and theca cells of lambs exposed to DES or BPA. An increase in GDF9 mRNA expression levels was observed in oFSH-primed lambs previously treated with DES or BPA50. In contrast, a decrease in BMPR1B was observed in BPA0.5-postnatally exposed lambs. The modifications in AR, GDF9, and BMPR1B may be associated with the altered ovarian function due to neonatal xenoestrogen exposure in response to an exogenous gonadotropin stimulus. These alterations may be the pathophysiological basis of subfertility syndrome in adulthood.

Androgens promote the acquisition of maturation competence in bovine oocytes

Recent studies in mice suggest that androgens are important for normal follicle development. However, there have been few reports concerning the action of androgens in the growth of oocytes from large animals. The purpose of this study was to determine the roles of androgens in bovine oocyte growth in vitro. Oocyte-granulosa cell complexes (OGCs) collected from 0.4-0.7 mm early antral follicles were cultured for 14 days with 17β-estradiol (E2) and a non-aromatizable androgen, dihydrotestosterone (DHT). We also examined the ability of an androgen receptor (AR) inhibitor, hydroxyflutamide, to antagonize the effect of androgens on the oocytes. During growth culture, the OGC structures collapsed in the medium with DHT alone, while in the presence of E2, the OGC structures were maintained. In the medium with both androgens and E2, the mean diameter of oocytes was increased from 95 μm to around 120 μm, larger than those grown with E2 alone (115 μm). Also in the maturation culture, oocytes grown with androgens (A4 or DHT) and E2 showed higher percentages of metaphase II oocytes (63% or 69%, respectively) than those grown with E2 alone (32%). Moreover, these maturation rates were decreased by hydroxyflutamide in a dose-dependent manner. Immunostaining showed that ARs were expressed in oocytes and granulosa cells in early antral follicles, and the nuclei of granulosa cells showed intense AR expression. In conclusion, although E2 supports the OGC structure, additional androgens promote oocyte growth and their acquisition of meiotic competence via AR during in vitro growth culture.

A low-testosterone state associated with endometrioma leads to the apoptosis of granulosa cells

Although endometriosis is suspected to be a cause of premature ovarian insufficiency (POI), the mechanism(s) underlying this process have not been elucidated. Recently, androgens were shown to promote oocyte maturation and to play a role in folliculogenesis. In addition, several reports have documented low testosterone levels in the follicular fluid obtained from endometriosis patients. We therefore examined whether the low levels of serum testosterone are associated with the apoptosis of granulosa cells in follicles obtained from endometriosis patients. Serum samples were collected from 46 patients with endometriosis and from 62 patients without endometriosis who received assisted reproductive therapy. Specimens of the ovaries obtained from 10 patients with endometrioma were collected using laparoscopy. The mean serum testosterone concentration in the patients with endometriosis was significantly lower than that observed in the patients without endometriosis. Furthermore, high expression of a pro-apoptotic Bcl-2 member, BimEL, in the follicles was found to be associated with a low serum testosterone level. We clarified the underlying mechanisms using a basic approach employing human immortalized granulosa cells derived from a primary human granulosa cell tumor, the COV434 cell line. The in vitro examination demonstrated that testosterone inhibited apoptosis induced by sex steroids depletion via the PI3K/Akt-FoxO3a pathway in the COV434 cells. In conclusion, we elucidated the mechanism underlying the anti-apoptotic effects of testosterone on granulosa cells, and found that a low-testosterone status is a potentially important step in the development of premature ovarian insufficiency in patients with endometriosis.

Androgen actions in the ovary: balance is key

For many decades, elevated androgens in women have been associated with poor reproductive health. However, recent studies have shown that androgens play a crucial role in women's fertility. The following review provides an overall perspective about how androgens and androgen receptor-mediated actions regulate normal follicular development, as well as discuss emerging concepts, latest perceptions, and controversies regarding androgen actions and signaling in the ovary.

Development of mammalian ovary

Pre-natal and early post-natal ovarian development has become a field of increasing importance over recent years. The full effects of perturbations of ovarian development on adult fertility, through environmental changes or genetic anomalies, are only now being truly appreciated. Mitigation of these perturbations requires an understanding of the processes involved in the development of the ovary. Herein, we review some recent findings from mice, sheep, and cattle on the key events involved in ovarian development. We discuss the key process of germ cell migration, ovigerous cord formation, meiosis, and follicle formation and activation. We also review the key contributions of mesonephric cells to ovarian development and propose roles for these cells. Finally, we discuss polycystic ovary syndrome, premature ovarian failure, and pre-natal undernutrition; three key areas in which perturbations to ovarian development appear to have major effects on post-natal fertility.