An imbalance between apoptosis and proliferation contributes to follicular persistence in polycystic ovaries in rats

Effects of melatonin and metformin on the ovaries of rats with polycystic ovary syndrome

OBJECTIVE

To study the combined and isolated effects of melatonin and metformin in the ovarian tissue of rats with PCOS.

DESIGN

Experimental study using a rat model of PCOS induced by continuous light exposure.

INTERVENTION(S)

Forty adult female rats were divided into 5 groups: physiological estrus phase (Sham); permanente estrus with PCOS induced by continuous lighting exposure for 60 consecutive days (control); with PCOS treated with melatonin; with PCOS treated with metformin; with PCOS treated with melatonin + metformin. After 60 days of treatments, all rats were killed, and ovaries were collected and processed for paraffin-embedding. Formalin-fixed paraffin-embedded sections were stained with hematoxylin and eosin or subjected to immunohistochemistry for proliferation (Ki-67) and apoptosis (cleaved caspase 3) detection markers.

SETTING

Federal University of São Paulo, Brazil.

ANIMALS

Forty adult female Wistar rats (Rattus norvegicus albinus).

MAIN OUTCOME MEASURE(S)

Number of corpus luteum and ovarian cysts, number of ovarian follicles (primary and antral follicles), number of interstitial cells, percentage of ovarian follicles (primary and antral follicles), and of interstitial cells immunostained to cleaved caspase-3 and Ki-67.

RESULTS

Absence of corpus luteum, a higher number of cysts, and increased nuclear volume and area of interstitial cells, along with a decrease in primary and antral follicle numbers, were noticed in the control group compared with the Sham group. Melatonin and metformin treatments attenuated these effects, although the combined treatment did not mitigate the increased number of cysts and ovaries induced by PCOS. An increase in theca interna cell apoptosis was observed in the control group, whereas melatonina and metformin treatments reduced it significantly. A higher percentage of caspase-3-immunostained granulosa cells was noted in the Sham and all treated groups compared with the control group; no aditive effects on ovarian cell apoptosis were observed in the combined treatment. The percentage of Ki-67- immunostained granulosa cells was significantly higher in the control group compared with the Sham group. However, the combined treatment, not melatonin and metformin alone, mitigated this effect. A higher percentage of Ki-67-immunostained interstitial cells was observed in all treated groups compared with the Sham and control groups, whereas no additive effects in that immunoreactivity were observed in the combined treatment.

CONCLUSIONS

Melatonin and metformin may improve ovarian function in rats with PCOS. The combined melatonin and metformin treatment is more effective in attenuating excessive granulosa cell proliferation, but it is not more effective in improving ovarian function than these drugs applied alone in rats with PCOS.

All-trans retinoic acid and fibroblast growth factor-2 enhance the fertility rate and embryo development in polycystic ovary syndrome mouse model

Objectives

Polycystic ovary syndrome (PCOS) causes a developmental arrest of antral follicles and disrupts oocyte maturation. Retinoic acid (RA) and Fibroblast Growth Factor-2 (FGF2) are effective in follicle growth, thus their effects on histopathology and in vitro fertility of oocytes were investigated in PCOS-induced mice.

Materials and Methods

Eighty female NMRI mice were randomly divided into 8 groups including 1-Normal mice, 2-PCOS mice without any treatment, 3-Normal mice treated with RA, 4-Normal mice treated with FGF2, 5-PCOS mice treated with RA, 6- PCOS mice treated with FGF2, 7- PCOS mice treated with RA and FGF2, and 8- Normal mice treated with RA and FGF2. Following PCOS induction, the mice were treated with intraperitoneal RA and FGF2 as a treatment. Then ovarian stimulation, for preparing the oocyte and embryo microscopic examinations was performed. After oocyte morphometry, through in vitro fertilization, the embryo formation was assessed. Data was analyzed by one-way ANOVA and Tukey tests.

Results

The results showed simultaneous injection of RA and FGF2 into PCOS-induced mice increases antral follicles and corpus luteum, but decreases cystic follicles. Simultaneous injection of these two substances into healthy mice increases the pre-antral follicles and corpus luteum. Simultaneous injection of RA and FGF2 increases the number of embryos in both control and intervention groups.

Conclusion

It can be concluded that RA and FGF2 increase the maturity of ovarian follicles, the number of two-celled embryos, and the number of grade-A embryos in mice with PCOS, which is more effective when these two substances are injected simultaneously.

Follicular Atresia, Cell Proliferation, and Anti-Mullerian Hormone in Two Neotropical Primates (Aotus nancymae and Sapajus macrocephalus)

This study evaluated the follicular atresia, cell proliferation, and anti-Mullerian hormone action in Aotus nancymae and Sapajus macrocephalus during three sexual phases (follicular, luteal, and gestational). Follicular quantification and immunolocalization of Caspase-3 protein, B-cell lymphoma 2 (BCL-2), proliferating cell nuclear antigen (PCNA), and anti-Mullerian hormone (AMH) were performed. A significant difference in the quantification between preantral and antral follicles, with a progressive decrease in the antrals, was identified. Protein and hormonal markers varied significantly between follicle cell types (A. nancymae p = 0.001; S. macrocephalus, p = 0.002). Immunostaining in the preantral and antral follicles was present in all sexual phases; for Caspase-3, in granulosa cells, oocytes, and stroma; for BCL-2, in granulosa cells, oocytes, and theca; and for PCNA and AMH, in oocytes and granulosa cells. The immunostaining for Caspase-3 was more expressive in the preantral follicles (follicular phase, p < 0.05), while that for BCL-2 and PCNA was more expressive in the antral follicles of the follicular phase. The AMH was more expressive in the primary and antral follicles of nonpregnant females, in both the follicular and luteal phases. Our results contribute to understanding the ovarian follicular selection, recruitment, and degeneration of these species.

The Role of Heat Shock Proteins in the Pathogenesis of Polycystic Ovarian Syndrome: A Review of the Literature

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder in women of reproductive age and post-menopausal women. PCOS is a multifactorial heterogeneous disorder associated with a variety of etiologies, outcomes, and clinical manifestations. However, the pathophysiology of PCOS is still unclear. Heat shock proteins (HSPs) have recently been investigated for their role in the pathogenesis of PCOS. HSPs are a class of proteins that act as molecular chaperones and maintain cellular proteostasis. More recently, their actions beyond that of molecular chaperones have highlighted their pathogenic role in several diseases. In PCOS, different HSP family members show abnormal expression that affects the proliferation and apoptotic rates of ovarian cells as well as immunological processes. HSP dysregulation in the ovaries of PCOS subjects leads to a proliferation/apoptosis imbalance that mechanistically impacts follicle stage development, resulting in polycystic ovaries. Moreover, HSPs may play a role in the pathogenesis of PCOS-associated conditions. Recent studies on HSP activity during therapeutic interventions for PCOS suggest that modulating HSP activity may lead to novel treatment strategies. In this review, we summarize what is currently known regarding the role of HSPs in the pathogenesis of PCOS and their potential role in the treatment of PCOS, and we outline areas for future research.

Ketogenic diet restores hormonal, apoptotic/proliferative balance and enhances the effect of metformin on a letrozole-induced polycystic ovary model in rats

OBJECTIVE

Polycystic ovaries (PCO) is a hormonal disorder that is a leading cause of infertility. The formation of multiple persistent cysts and hormonal imbalance are hallmarks of PCO. Recent clinical studies reported a beneficial effect of the ketogenic diet (KD; high-fat, low-carbohydrate) on PCO. The aim of this study was to investigate the effect of the KD alone and in combination with metformin on letrozole-induced PCO in female rats.

METHODS

Female rats were grouped into control and PCO (letrozole; 1 mg/kg for 21 days). The PCO group was subdivided into PCO (non-treated), PCO-metformin (300 mg/kg), PCO rats fed with KD only, and PCO rats treated with metformin and fed with KD. All groups continued to receive letrozole during the 21-day treatment period. At the end of the experiment, serum and ovaries were collected for further analysis.

RESULTS

The untreated-PCO rats showed increased testosterone, LH/FSH ratio, and ovary weights. Disturbed apoptosis and proliferation balance were evident as a low caspase-3 activation and proliferating cell nuclear antigen expression and increased TGF-β expression. The KD improved the letrozole-induced effects, which was comparable to the effect of metformin. Combining the KD with metformin treatment additively enhanced the metformin effect.

CONCLUSION

Our results indicate that the KD has a protective role against PCO in rats, especially when combined with metformin. This study reveals a potential therapeutic role of the KD in PCO, which could prompt valuable future clinical applications.

Concentrated ambient fine particles exposure affects ovarian follicle development in mice

BACKGROUND

Ambient fine particles (PM_2.5) are known to cause various reproductive and developmental diseases. However, the potential mechanisms of PM_2.5 exposure induced female reproductive damage remain unclear.

METHODS

Four weeks old female C57BL/6 J mice were exposed to filtered air (FA, n = 10) or concentrated ambient PM_2.5 (CAP, n = 10) using a versatile aerosol concentration enrichment system. After 9 weeks of the exposure, mice were sacrificed under sevoflurane anesthesia and tissue samples were collected. Immunohistochemical analysis, enzyme-linked immunosorbent assay, quantitative polymerase chain reaction, and RNA-sequencing were performed to analyze the effects of PM_2.5 exposure on follicle development and elucidate its potential mechanisms.

RESULTS

Chronic PM_2.5 exposure resulted in follicular dysplasia. Compared to the FA-exposed group, follicular atresia in the CAP-exposed mice were significantly increased. Further studies confirmed that CAP induced apoptosis in granulosa cells, accompanied by a distortion of hormone homeostasis. In addition, RNA-sequencing data demonstrated that CAP exposure induced the alteration of ovarian gene expressions and was associated with inflammatory response.

CONCLUSIONS

Chronic exposure to CAP can induce follicular atresia, which was associated with hormone modulation and inflammation.

Diacerein ameliorates induced polycystic ovary in female rats via modulation of inflammasome/caspase1/IL1β and Bax/Bcl2 pathways

Polycystic ovary syndrome (PCOS) is a very common gynecological disease during childbearing period and markedly affects female fertility. Until now, there are no studies evaluating the possible curative effect of diacerein (DIA) in induced PCOS. For the first time, we aimed in current model to study the effect of DIA (50 mg/kg/day) orally for 3 weeks on experimentally induced PCOS by letrozole (1 mg/kg/day) for 3 weeks. We measured rats' body weight changes, levels of serum insulin, anti-Müllerian hormone (AMH), testosterone, inflammasome, caspase1, and total anti-oxidant capacity (TAC). Moreover, we measured ovarian tissue parameters as malondialdehyde (MDA), interleukin 1β (IL1β), real-time polymerase chain reaction (rt-PCR) of Bcl2-associated X protein (Bax), and interleukin 10 (IL10) gene expression changes. Furthermore, histopathological features and anti-apoptotic marker B cell lymphoma 2 (Bcl2) immunoexpression changes were evaluated. Our results showed that letrozole markedly induced PCOS as manifested by significant increase in serum testosterone, insulin, AMH, rats' body weights, ovarian tissue MDA, IL1β, inflammasome, and caspase1 but decrease of serum TAC. In addition, gene expression of Bax increased but IL10 gene expression decreased. Ovaries showed the typical histopathological changes of PCOS with no immunoexpression of Bcl2. DIA was greatly able to ameliorate letrozole-induced PCOS changes in rats mainly via prevention of IL1β, and improving metabolic disturbances, and its anti-apoptotic, anti-oxidant, and anti-inflammatory effects with further regulation of inflammasome/caspase1/IL1β and Bax/Bcl2 pathways.

Ovarian Toxicity Induced by Aluminum Chloride: Alteration of Cyp19a1, Pcna, Puma, and Map1lc3b genes Expression

Aluminum (Al) is an abundant metal with wide application in our daily lives including medicine, industry, cosmetics, and packaging. After entrance to the body, aluminum binds to transferrin and reaches different tissues. Al is a metalloestrogen that can lead to oxidative stress (OxS) and endocrine disruption. No detailed study can be found addressing the effect of Al on the ovary and granulosa cells (GCs). In this study, the focus is on the treated ovaries and GCs of NMRI mice exposed to low, middle, and high doses of aluminum chloride (AlCl₃) via in vitro and in vivo assays. The steroidogenic, proliferative, apoptotic, and autophagic-related genes were examined. Up-regulated expression of steroidogenic and proliferative genes was detected. The observed apoptotic and autophagic genes had variable expression. Interrupted ovarian structure, disrupted folliculogenesis, presence of Call-Exner bodies, overexpression of steroidogenic gene, and unbalanced apoptosis/autophagy and proliferation resembled features of granulosa cell tumor (GCT).

A high-androgen microenvironment inhibits granulosa cell proliferation and alters cell identity

A naturally occurring bovine model with excess follicular fluid androstenedione (High A4), reduced fertility, and polycystic ovary syndrome (PCOS)-like characteristics has been identified. We hypothesized High A4 granulosa cells (GCs) would exhibit altered cell proliferation and/or steroidogenesis. Microarrays of Control and High A4 GCs combined with Ingenuity Pathway Analysis indicated that High A4 GCs had cell cycle inhibition and increased expression of microRNAs that inhibit cell cycle genes. Granulosa cell culture confirmed that A4 treatment decreased GC proliferation, increased anti-Müllerian hormone, and increased mRNA for CTNNBIP1. Increased CTNNBIP1 prevents CTNNB1 from interacting with members of the WNT signaling pathway thereby inhibiting the cell cycle. Expression of CYP17A1 was upregulated in High A4 GCs presumably due to reduced FOS mRNA expression compared to Control granulosa cells. Furthermore, comparisons of High A4 GC with thecal and luteal cell transcriptomes indicated an altered cellular identity and function contributing to a PCOS-like phenotype.

A new isolation and culture method for granulosa cells

Granulosa cells are the cell population who have an increasing importance in the female genital system and reproduction. Thus, nowadays in vitro studies to address these cells are also gaining importance and attracts researcher's attention. The aim of our study is to develop a more feasible, low-cost granulosa cell isolation and culture method compared to methods defined so far. Granulosa cells were isolated from follicular fluids obtained from both healthy women donors (n = 19) and polycystic ovary syndrome (n = 15) applied to in vitro fertilization treatment process. Granulosa cells were isolated by using Lymphosep® separation fluid that was not used for this purpose before. The isolated cells were cultured in suitable culture dishes with a mixture of BIO-AMFTM-1 and DMEM/F12 in the first seeding and only complete DMEM/F12 in the following feeds. Complete medium contains only 5% fetal calf serum, 4% L-glutamine and 1% penicillin-streptomycin-amphotericin. The new methods we have developed in granulosa cell isolation and in vitro culture have been successful. Reduction in supplement types and amount; improved the proliferation rate of the granulosa cells in culture. Our new methods of isolation and cell culture for granulosa cells from healthy women, have been also successful in samples of polycystic ovarian patients. With these developed methods, granulosa cells, which belong to humans and have an important role in the ovary, could be isolated and subsequently be maintained to reproduce (proliferate) more easily and cheaper.

Potential Therapeutic Effect of Bee Pollen and Metformin Combination on Testosterone and Estradiol Levels, Apoptotic Markers and Total Antioxidant Capacity in A Rat Model of Polycystic Ovary Syndrome

Background

Polycystic ovary syndrome (PCOS) is associated with metabolic disorder as well as infertility. Many traditional remedies have been reported to show estrogenic and antioxidant potential. Bee pollen is a natural com- pound, reported as one such remedy. The present study aimed to investigate the effects of BP extract and metformin (MET) on estradiol (E2) and testosterone (T) levels, apoptotic markers, and total antioxidant capacity (TAC) inarat model of PCOS.

Materials and Methods

In this experimental study, 54 female Wistar (n=6/group) rats received 2 mg of estradiol valerate (EV) intramuscularly and 6 additional rats were considered the control without EV injection. The rats were treated with BP (50, 100, and 200 mg/kg), MET (300 mg/kg) and BP+MET (50 BP+300 MET, 100 BP+300 MET, and 200 BP+300 MET mg/kg). Serum levels of E2 and T were assessed by ELISA method. TAC of serum was also determined. The expressions of Bcl-2, Bax and Caspase-3 (Cas-3), and Sirt-1 genes were evaluated by real-time poly- merase chain reaction (PCR). Data were statistically analyzed using one-way ANOVA.

Results

In the untreated PCOS group E2 and T levels (P<0.01), and Bcl-2 (P=0.007) expression were increased, but TAC (P=0.002) and expression of Bax (P=0.001), Cas-3 and Sirt1 (P<0.01) were decreased significantly. The levels of E2 and T, as well as the expressions of Bcl-2 were decreased in all treated groups compared to the untreated PCOS group (P<0.01). On the other hand, TAC and expression of Bax, Cas-3 and Sirt1 were increased in the BP- and MET-treated groups (P<0.05).

Conclusion

BP and MET synergistically improved serum E2, T and TAC levels, and expression of apoptotic genes.

A review of the physiology behind letrozole applications in infertility: are current protocols optimal?

Letrozole is a targeted aromatase inhibitor which has primarily been used in post-menopausal women with breast cancer. Recently, it has been utilized in infertile pre-menopausal women because of its ability to enhance FSH production for ovulation induction. However, the ovarian follicle’s response to FSH is only a part of the endocrine events occurring in a developing follicle. The health of the small antral follicles is driven primarily by androgens, which contribute to granulosa cell mitosis, sensitivity to FSH, and resistance to atresia. In contrast, elevated androgens in the late antral to pre-ovulatory follicle have a negative impact on follicle health and lead to atresia and cystic follicle formation. This ovarian physiologic data suggests that current applications of letrozole to infertility may be squandering some of the primary benefits available in using letrozole to promote follicle development. Four applications of letrozole to infertility that have appeared in the medical literature are reviewed. Androgen-related benefits are reviewed and various questions put forward about how letrozole could be more effectively used to help patients in these settings.

Expression profiling of primary cultured buffalo granulosa cells from different follicular size in comparison with their in vivo counterpart

This study aimed to: (i) characterize cultured granulosa cells (GCs) from different follicle sizes morphologically and molecularly; and (ii) select a suitable model according to follicular size that maintained GC function during culture. Buffalo ovaries were collected from a slaughterhouse and follicles were classified morphologically into: first group ≤ 4 mm, second group 5-8 mm, third group 9-15 mm and fourth group 16-20 mm diameter. GC pellets were divided into two portions. The first portion served as the control fresh pellet, and the secondwas used for 1 week for GC culture. Total RNA was isolated, and qRT-PCR was performed to test for follicle-stimulating hormone receptor (FSHR), cytochrome P450 19 (CYP19), luteinizing hormone/choriogonadotropin receptor (LHCGR), proliferating cell nuclear antigen (PCNA), apoptosis-related cysteine peptidase (CASP3), anti-Müllerian hormone (AMH), and phospholipase A2 group III (PLA2G3) mRNAs. Estradiol (E2) and progesterone (P4) levels in the culture supernatant and in follicular fluids were measured using enzyme-linked immunosorbent assay (ELISA). Basic DMEM-F12 medium maintained the morphological appearance of cultured GCs. The relative abundance of FSHR, CYP19, and LHCGR mRNAs was 0.001 ≤ P ≤ 0.01 and decreased at the end of culture compared with the fresh pellet. There was a fine balance between expression patterns of the proliferation marker gene (PCNA) and the proapoptotic marker gene (CASP3). AMH mRNA was significantly increased (P < 0.001) in cultured GCs from small follicles, while cultured GCs from other three categories (5-8 mm, 9-15 mm and 16-20 mm) showed a clear reduction (P < 0.001). Interestingly, the relative abundance of PLA2G3 mRNA was significantly (P < 0.001) increased in all cultured GCs. E2 and P4 concentrations were significantly (P < 0.001) decreased in all cultured groups. Primary cultured GCs from small follicles could be a good model for better understanding follicular development in Egyptian buffaloes.

Thyroid hormones and female reproduction

Thyroid hormones are vital for the proper functioning of the female reproductive system, since they modulate the metabolism and development of ovarian, uterine, and placental tissues. Therefore, hypo- and hyperthyroidism may result in subfertility or infertility in both women and animals. Other well-documented sequelae of maternal thyroid dysfunctions include menstrual/estral irregularity, anovulation, abortion, preterm delivery, preeclampsia, intrauterine growth restriction, postpartum thyroiditis, and mental retardation in children. Several studies have been carried out involving prospective and retrospective studies of women with thyroid dysfunction, as well as in vivo and in vitro assays of hypo- and hyperthyroidism using experimental animal models and/or ovarian, uterine, and placental cell culture. These studies have sought to elucidate the mechanisms by which thyroid hormones influence reproduction to better understand the physiology of the reproductive system and to provide better therapeutic tools for reproductive dysfunctions that originate from thyroid dysfunctions. Therefore, this review aims to summarize and update the available information related to the role of thyroid hormones in the morphophysiology of the ovary, uterus, and placenta in women and animals and the effects of hypo- and hyperthyroidism on the female reproductive system.

Lectin histochemical pattern on the normal and cystic ovaries of sows

The lectin histochemical pattern (LHP) was characterized and compared in normal and cystic ovaries of sows. Six biotinylated lectins (PNA, SBA, WGA, RCA-1, DBA and UEA-1) were used on tissue sections. In the normal ovaries, the reaction to UEA-1 and SBA was mild to moderate in mesothelial and endothelial cells. RCA-1 staining was mild to moderate in theca interna of growing follicles, corpora luteum and mesothelium. In addition, this lectin presented strong reaction in endothelial cells, granulosa cells of atretic follicles, zona pellucida of growing follicles and plasma. DBA showed strong intensity in mesothelial and endothelial cells. There was mild to moderate reactivity to WGA in granulosa cells, corpus luteum and theca interna of follicles in development, and moderate in zona pellucida, in granulosa cells of atretic follicles and mesothelium. PNA staining was mild to moderate in oocytes and in the adventitia and media of medullary arteries. Changes in the LHP of the cystic ovaries were noted; however, there were no differences in these findings between the follicular and luteinized cysts. UEA-1 reactivity in the cystic ovaries was moderately reduced in the mesothelial and endothelial cells, whereas there was mild reduction in the DBA staining in the granulosa cells. Reaction to RCA-1 and WGA in the cysts also was decreased in theca interna, zona pellucida and granulosa cells of atretic follicles. Furthermore, endothelium and theca interna in the cystic ovaries presented mild reduction of marcation to SBA, whereas there was decreased reactivity to PNA in the oocytes and adventitia and media layers of the medullary arteries. The results of the current study show that cysts modify the LHP in swine ovaries. These changes of glycoconjugates in many ovarian structures could modify diverse process and may be one of the reasons for decreased fertility in sows.

Experimental polycystic ovarian syndrome is associated with reduced expression and function of P2Y2 receptors in rat theca cells

Extracellular purines through specific receptors have been recognized as new regulators of ovarian function. It is known that P2Y2 receptor activity induces theca cell proliferation, we hypothesized that purinergic signaling controls the changes related to hyperthecosis in polycystic ovarian syndrome (PCOS). The aim of this study was to analyze the expression of UTP-sensitive P2Y receptors and their role in theca cells (TC) proliferation in experimentally-induced PCOS (EI-PCOS). In primary cultures of TC from intact rats, all the transcripts of P2Y receptors were detected by polymerase chain reaction; in these cells, UTP (10 μM) induced extracellular signal-regulated kinases (ERK) phosphorylation. Rats with EI-PCOS showed a reduced expression of P2Y2R in TC whereas P2Y4R did not change. By analyzing ERK phosphorylation, it was determined that P2Y2R is the most relevant receptor in TC. UTP promoted cell proliferation in TC from control but not from EI-PCOS rats. The in silico analysis of P2yr2 promoter indicated the presence of androgen response elements; the stimulation of TC primary cultures with testosterone promoted a significant reduction in the expression of the P2yr2 transcript. We concluded that P2Y2R participates in controlling the proliferative rate of TCs from healthy ovaries, but this regulation is lost during EI-PCOS.

Long non-coding RNA LINC-01572:28 inhibits granulosa cell growth via a decrease in p27 (Kip1) degradation in patients with polycystic ovary syndrome

BACKGROUND

Disordered folliculogenesis is a key feature of polycystic ovary syndrome (PCOS), but the underlying molecular mechanism remains unclear.

METHODS

Long non-coding RNA (lncRNA) expression in luteinized granulosa cells (hLGCs) derived from women with and without PCOS were analyzed using microarray and qRT-PCR. Immortalized human granulosa cell lines were cultured for proliferation assays after transfection with the LINC-01572:28 over-expression vector in the presence or absence of p27 siRNA. Protein expression analysis, rescue assays, and RNA immunoprecipitation (RIP) were used to confirm the LINC-01572:28 substrate.

FINDINGS

LINC-01572:28 and p27 protein were elevated whereas proliferating cell nuclear antigen protein was decreased in the hLGCs of women with PCOS. LINC-01572:28 expression was positively correlated with basal testosterone levels. Over-expression of LINC-01572:28 inhibited cell proliferation and impeded G1/S transition, which were partially reversed by siRNA-mediated p27 knockdown.

INTERPRETATION

Our findings, therefore, suggest that LINC-01572:28 suppresses cell proliferation and cell cycle progression by reducing the degradation of p27 protein via SKP2 binding.

Pleiotropic roles of melatonin in endometriosis, recurrent spontaneous abortion, and polycystic ovary syndrome

Melatonin is a neurohormone synthesized from the aromatic amino acid tryptophan mainly by the pineal gland of mammals. Melatonin acts as a broad-spectrum antioxidant, powerful free radical scavenger, anti-inflammatory agent, anticarcinogenic factor, sleep inducer and regulator of the circadian rhythm, and potential immunoregulator. Melatonin and reproductive system are interrelated under both physiological and pathological conditions. Oxidative stress, inflammation, and immune dysregulation are associated with the pathogenesis of the female reproductive system which causes endometriosis (EMS), recurrent spontaneous abortion (RSA), and polycystic ovary syndrome (PCOS). Accumulating studies have indicated that melatonin plays pleiotropic and essential roles in these obstetrical and gynecological disorders and would be a candidate therapeutic drug to regulate inflammation and immune function and protect special cells or organs. Here, we systematically review the pleiotropic roles of melatonin in EMS, RSA, and PCOS to explore its pathological implications and treatment potential.

Purinergic Signalling: Therapeutic Developments

Purinergic signalling, i.e., the role of nucleotides as extracellular signalling molecules, was proposed in 1972. However, this concept was not well accepted until the early 1990's when receptor subtypes for purines and pyrimidines were cloned and characterised, which includes four subtypes of the P1 (adenosine) receptor, seven subtypes of P2X ion channel receptors and 8 subtypes of the P2Y G protein-coupled receptor. Early studies were largely concerned with the physiology, pharmacology and biochemistry of purinergic signalling. More recently, the focus has been on the pathophysiology and therapeutic potential. There was early recognition of the use of P1 receptor agonists for the treatment of supraventricular tachycardia and A2A receptor antagonists are promising for the treatment of Parkinson's disease. Clopidogrel, a P2Y12 antagonist, is widely used for the treatment of thrombosis and stroke, blocking P2Y12 receptor-mediated platelet aggregation. Diquafosol, a long acting P2Y2 receptor agonist, is being used for the treatment of dry eye. P2X3 receptor antagonists have been developed that are orally bioavailable and stable in vivo and are currently in clinical trials for the treatment of chronic cough, bladder incontinence, visceral pain and hypertension. Antagonists to P2X7 receptors are being investigated for the treatment of inflammatory disorders, including neurodegenerative diseases. Other investigations are in progress for the use of purinergic agents for the treatment of osteoporosis, myocardial infarction, irritable bowel syndrome, epilepsy, atherosclerosis, depression, autism, diabetes, and cancer.

Altered Expression of Pro-inflammatory Cytokines in Ovarian Follicles of Cows with Cystic Ovarian Disease

A growing body of evidence suggests that ovulation shares many of the features of an inflammatory reaction and that cytokines play many diverse and important roles in reproductive biology. The aim of this study was to examine the expression of the pro-inflammatory cytokines interleukin (IL)-1α, IL-6 and tumour necrosis factor (TNF)-α in ovarian cells from cows with cystic ovarian disease (COD) as compared with that in ovarian structures from regularly cycling cows. Expression of genes encoding IL-1α, IL-6 and TNF-α was detected by real-time polymerase chain reaction in follicular cells from ovaries from healthy cows and cows with COD with no significant differences. However, immunohistochemistry showed increased expression of IL-1α, IL-6 and TNF-α in cystic follicles, suggesting that this expression may be related to the persistence of follicular cysts. The effect of COD was evident for IL-1α and TNF-α, and a follicular structure-disease interaction was observed in the expression of all the cytokines evaluated. Thus, altered expression of these proinflammatory cytokines may be related to ovulation failure and development of follicular cysts.

Involvement of PAPP-A and IGFR1 in Cystic Ovarian Disease in Cattle

Cystic ovarian disease (COD) is one of the main causes of infertility in dairy cattle. It has been shown that intra-ovarian factors, such as members of the insulin-like growth factor (IGF) system, may contribute to follicular persistence. The bioavailability of IGF to initiate its response by binding to specific receptors (IGFRs) depends on interactions with related compounds, such as pregnancy-associated plasma protein A (PAPP-A). The aim of this study was to determine IGFR1 and PAPP-A expression both in follicles at different stages of development and in cysts, to evaluate the roles in the etiopathogenesis of COD in cattle. The mRNA expression of PAPP-A was higher in granulosa cells of large tertiary follicles than in cysts, whereas the protein PAPP-A present in the follicular fluid from these follicles showed no differences. Although no PAPP-A mRNA expression was detected in smaller tertiary follicles, in their follicular fluid, this protease was detected in lesser concentration than in cysts. The mRNA expression of IGFR1 was lower in granulosa cells from cystic follicles than in those from tertiary ones. However, the protein expression of this receptor presented the highest levels in cystic structures, probably to increase the possibility of IGF response. The data obtained would indicate that animals with COD have an altered regulation of the IGF system in the ovary, which could be involved in the pathogenesis of this disease in cattle.

Molecular aspects of bovine cystic ovarian disease pathogenesis

Cystic ovarian disease (COD) is one of the main causes of reproductive failure in cattle and causes severe economic loss to the dairy farm industry because it increases both days open in the post partum period and replacement rates due to infertility. This disease is the consequence of the failure of a mature follicle to ovulate at the time of ovulation in the estrous cycle. This review examines the evidence for the role of altered steroid and gonadotropin signaling systems and the proliferation/apoptosis balance in the ovary with cystic structures. This evidence suggests that changes in the expression of ovarian molecular components associated with these cellular mechanisms could play a fundamental role in the pathogenesis of COD. The evidence also shows that gonadotropin receptor expression in bovine cystic follicles is altered, which suggests that changes in the signaling system of gonadotropins could play a fundamental role in the pathogenesis of conditions characterized by altered ovulation, such as COD. Ovaries from animals with COD exhibit a disrupted steroid receptor pattern with modifications in the expression of coregulatory proteins. These changes in the pathways of endocrine action would trigger the changes in proliferation and apoptosis underlying the aberrant persistence of follicular cysts.

Free Spanish abstract: A Spanish translation of this abstract is freely available at http://www.reproduction-online.org/content/149/6/R251/suppl/DC1.

Defective CFTR-regulated granulosa cell proliferation in polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is one of the most frequent causes of female infertility, featured by abnormal hormone profile, chronic oligo/anovulation, and presence of multiple cystic follicles in the ovary. However, the mechanism underlying the abnormal folliculogenesis remains obscure. We have previously demonstrated that CFTR, a cAMP-dependent Cl(-) and HCO3 (-) conducting anion channel, is expressed in the granulosa cells and its expression is downregulated in PCOS rat models and human patients. In this study, we aimed to investigate the possible involvement of downregulation of CFTR in the impaired follicle development in PCOS using two rat PCOS models and primary culture of granulosa cells. Our results indicated that the downregulation of CFTR in the cystic follicles was accompanied by reduced expression of proliferating cell nuclear antigen (PCNA), in rat PCOS models. In addition, knockdown or inhibition of CFTR in granulosa cell culture resulted in reduced cell viability and downregulation of PCNA. We further demonstrated that CFTR regulated both basal and FSH-stimulated granulosa cell proliferation through the HCO3 (-)/sAC/PKA pathway leading to ERK phosphorylation and its downstream target cyclin D2 (Ccnd2) upregulation. Reduced ERK phosphorylation and CCND2 were found in ovaries of rat PCOS model compared with the control. This study suggests that CFTR is required for normal follicle development and that its downregulation in PCOS may inhibit granulosa cell proliferation, resulting in abnormal follicle development in PCOS.

Cytoskeletal proteins in the follicular wall of normal andcystic ovaries of sows

The expression of cytoskeletal proteins was evaluated immunohistochemically in 36 normal ovaries sampled from 18 sows and 44 cystic ovaries sampled from of 22 sows, was evaluated. All sows had history of reproductive problems, such as infertility or subfertility. The immunohistochemically stained area (IHCSA) was quantified through image analysis to evaluate the expression of these proteins in the follicular wall of secondary, tertiary, and cystic follicles. Cytokeratins (CK) immunoreactivity was strong in the granulosa cell layer (GC) and mild in the theca interna (TI) and externa (TE) of the normal follicles. There was severe reduction of the reaction to CK in the GC in the cystic follicles, mainly in the luteinized cysts. The immunoreactivity for vimentin was higher in the GC from normal and cystic follicles in contrast with the other follicular structures. In the luteinized cysts, the IHCSA for vimentin was significantly higher in TI and in both observed cysts, the labeling was more accentuated in TE. Immunohistochemical detection of desmin and α-SMA was restricted to the TE, without differences between the normal and cystic follicles. The results of the current study show that the development of ovarian cysts in sows is associated to changes in the expression of the cytoskeletal proteins CK and vimentin.

mRNA expression pattern of gonadotropin receptors in bovine follicular cysts

Follicular growth and steroidogenesis are dependent on gonadotropin binding to their receptors in granulosa and theca cells of ovarian follicles. The aim of the present study was to evaluate the expression patterns of follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHCGR) in ovarian follicular structures from cows with cystic ovarian disease (COD) as compared with those of regularly cycling cows. Relative real-time RT-PCR analysis showed that the expression of FSHR mRNA in granulosa cells was highest in small antral follicles, then decreased significantly as follicles increased in size, and was lowest in cysts. FSHR mRNA was not detected in the theca cells of any follicular category, including cysts. LHCGR mRNA expression in granulosa cells was significantly higher in large antral follicles than in cysts, and not detected in granulosa cells of small and medium antral follicles. In theca cells, the expression level of LHCGR mRNA in medium antral follicles was higher than in small and large antral follicles, whereas that in follicular cysts it was similar to those in small and medium antral follicles, but higher than that in large antral follicles. Our findings provide evidence that there is an altered gonadotropin receptor expression in bovine cystic follicles, and suggest that in conditions characterized by altered ovulation, such as COD, changes in the signaling system of gonadotropins may play a fundamental role in their pathogenesis.

Immunohistochemical evaluation of proliferation, apoptosis and steroidogenic enzymes in the ovary of rats with polycystic ovary

Objective: to evaluate the immunohistochemical expression of proliferative, apoptotic and steroidogenic enzyme markers in the ovaries of rats with polycystic ovary syndrome (PCOS). Methods: twenty rats were divided into two groups: GCtrl - estrous phase, and PCOS - with polycystic ovaries. The GCtrl animals were subjected to a lighting period from 7 am to 7 pm, while the animals with PCOS group remained with continuous lighting for 60 days. Subsequently, the animals were anesthetized, the ovaries were removed and fixed in 10% formaldehyde, prior to paraffin embedding. Sections were stained using H.E. or subjected to immunohistochemical methods for the detection of Ki-67, cleaved caspase-3, CYP11A1, CYP17A1 and CYP19A1. The results were analyzed using Student's t-test (p < 0,05). Results: morphological results showed evidence of interstitial cells originating from the inner theca cells of degenerating ovarian cysts in PCOS. Immunoexpression of Ki-67 was higher in the granulosa cells in GCtrl, and the theca interna cells in PCOS, while cleaved caspase-3 was higher in granulosa cells of ovarian cysts from PCOS and in the theca interna cells of GCtrl. Immunoreactivity of CYP11A1 in the theca interna, granulosa and interstitial cells was similar between the two groups, while CYP17A1 and CYP19A1 were higher in the granulosa and interstitial cells in the PCOS group. Conclusion: the results indicate that the interstitial cells are derived from the theca interna and that enzymatic changes occur in the theca interna and interstitial cells in ovaries of rats with PCOS, responsible for the high levels of androgens and estradiol.

Role of activin, inhibin, and follistatin in the pathogenesis of bovine cystic ovarian disease

Cystic ovarian disease (COD) is an important cause of infertility in dairy cattle. Although many researchers have focused their work on the endocrine changes related to this disease, evidence indicates that intraovarian components play an important role in follicular persistence. Activin, inhibin, and follistatin participate as intraovarian regulatory molecules involved in follicular cell proliferation, differentiation, steroidogenesis, oocyte maturation, and corpus luteum function. Given the importance of these factors in folliculogenesis, we examined the expression and immunolocalization of activin/inhibin βA-subunit, inhibin α-subunit, and follistatin in the ovaries of healthy estrus-synchronized cows and in those of cows with spontaneous or adrenocorticotropic hormone (ACTH)-induced COD. We also studied inhibin B (α βB) levels in serum and follicular fluid. We found an increased expression of the βA-subunit of activin A/inhibin A, the α-subunit of inhibin, and follistatin in granulosa cells of spontaneous follicular cysts by immunohistochemistry, and decreased concentrations of inhibin B (α βB) in the follicular fluid of spontaneous follicular cysts. These results, together with those previously obtained, indicate that the expression of the components of the activin-inhibin-follistatin system is altered. This could lead to multiple alterations in important functions in the ovary like the balance between pro- and anti-apoptotic factors, follicular proliferation/apoptosis, and steroidogenesis, which may contribute to the follicular persistence and endocrine changes found in cattle with COD.

Purinergic signalling in the reproductive system in health and disease

There are multiple roles for purinergic signalling in both male and female reproductive organs. ATP, released as a cotransmitter with noradrenaline from sympathetic nerves, contracts smooth muscle via P2X1 receptors in vas deferens, seminal vesicles, prostate and uterus, as well as in blood vessels. Male infertility occurs in P2X1 receptor knockout mice. Both short- and long-term trophic purinergic signalling occurs in reproductive organs. Purinergic signalling is involved in hormone secretion, penile erection, sperm motility and capacitation, and mucous production. Changes in purinoceptor expression occur in pathophysiological conditions, including pre-eclampsia, cancer and pain.

Alteration in localization of steroid hormone receptors and coregulatory proteins in follicles from cows with induced ovarian follicular cysts

Cystic ovarian disease (COD) is an important cause of infertility in cattle. The altered follicular dynamics and cellular differentiation observed in COD may be mediated through a disruption of the expression of steroid receptors and their associated transcriptional cofactors. The aim of this study was to determine the protein expression profiles of ESR1, ESR2, PGR, AR, NCOA3, NCOR2, and PHB2 (REA) in ovarian follicles in an experimental model of COD induced by the administration of ACTH. Ovaries were collected and follicles were dissected from heifers during the follicular phase (control) or from heifers treated with ACTH to induce the formation of ovarian follicular cysts. Ovaries were fixed, sectioned, and stained immunohistochemically for steroid receptors and the associated transcription factors. The relative expression of ESR1 was similar in follicular cysts and in tertiary follicles from both control and cystic cows and was significantly higher than in secondary follicles. The expression of ESR2 in the granulosa was higher in cystic follicles. No differences were seen for PGR. The expression of androgen receptor was significantly increased in tertiary follicles with lower immunostaining in cysts. The expression of NCOA3 was observed in the granulosa and theca with a significantly increased expression in the theca interna of cystic follicles. The highest levels of NCOR2 expression in granulosa, theca interna, and theca externa were observed in cysts. In granulosa cells, NCOR2 levels increase progressively as follicles mature and the treatment had no effect. In summary, ovaries from animals with induced COD exhibited altered steroid receptor expression compared with normal animals, as well as changes in the expression of their regulators. It is reasonable to suggest that in conditions characterized by altered ovulation and follicular persistence, such as COD, changes in the intra-ovarian expression of these proteins could play a role in their pathogenesis.

Developmental programming: impact of prenatal testosterone excess on ovarian cell proliferation and apoptotic factors in sheep

Prenatal testosterone (T) excess leads to reproductive dysfunctions in sheep, which include increased ovarian follicular recruitment and persistence. To test the hypothesis that follicular disruptions in T sheep stem from changes in the developmental ontogeny of ovarian proliferation and apoptotic factors, pregnant Suffolk sheep were injected twice weekly with T propionate or dihydrotestosterone propionate (DHT; a nonaromatizable androgen) from Days 30 to 90 of gestation. Changes in developmental expression of proliferating cell nuclear antigen (PCNA), BCL2, BAX, activated CASP3, and FAS/FASLG were determined at Fetal Days 90 and 140, 22 wk, 10 mo, and 21 mo of age by immunocytochemisty. Prenatal T treatment induced changes in expression of proliferative and apoptotic markers in a follicle-, age-, and steroid-specific manner. Changes in BAX were evident only during fetal life and PCNA, BCL2, and CASP3 only postnatally. Prenatal T and not DHT increased PCNA and decreased BCL2 in granulosa/theca cells of antral follicles at 10 and 21 mo but decreased CASP3 in granulosa/theca cells of antral follicles at 22 wk (prepubertal) and 10 and 21 mo. Both treatments decreased BAX immunostaining in granulosa cells of Fetal Day 90 primordial/primary follicles. Neither treatment affected FAS expression at any developmental time point in any follicular compartment. Effects on BAX appear to be programmed by androgenic actions and PCNA, BCL2, and CASP3 by estrogenic actions of T. Overall, the findings demonstrate that fetal exposure to excess T disrupts the ovarian proliferation/apoptosis balance, thus providing a basis for the follicular disruptions evidenced in these females.

Follicular populations, recruitment and atresia in the ovaries of different strains of mice

Follicular atresia is a key event in the selection of the ovulatory follicles and occurs during all developmental stages. The aims of the study were to evaluate the follicular population as well as the rates of follicular recruitment and atresia in different strains of mice. Ovaries were obtained from four strains of mice: G1/ Swiss, G2/ F1 Swiss×C57BL/6, G3/ inbred strain C57BL/6, and G4/ F1 C57BL/6×Swiss. All mice used in the study were 60 days old. Ovaries collected from the mice were fixed and processed for histological analysis. The G2 ovaries were also used to examine immunolocalization of active caspase-3. The pimordial follicle population was smaller in G3 mice than in G1, G2 and G4 groups (7 565±1 845 vs. 17 180±3 159, 14 785±3 319 and 13 325±2 685, respectively; p<0.05). The rate of follicular recruitment in G3, however, was higher than in the other groups (29.2% vs. 18.2%, 17.3% and 13.0% in G1, G2 and G4, respectively; p<0.05), resulting in a similar (p>0.05) number of antral follicles among groups. The small follicular pool in G3 mice was also associated with a lower rate of follicular atresia (11.4% vs. 17.2%, 16.7% and 13.6% for G3, G1, G2 and G4, respectively; p<0.05). The number of follicles stained with active caspase-3 was higher (p<0.05) during the final stage of preantral folliculogenesis than in other stages of follicular development suggesting that apoptosis in mice occurs earlier in comparison to large animals. Thus, it was concluded that differences in follicle reservoir among mice strains are compensated by an increased rate of follicular recruitment and a decreased rate of follicular atresia; and atresia occurs in mice mainly at the end of the preantral stage of folliculogenesis.

Functional expression and intracellular signaling of UTP-sensitive P2Y receptors in theca-interstitial cells

BACKGROUND

Purinergic receptors are expressed in the ovary of different species; their physiological roles remain to be elucidated. UTP-sensitive P2Y receptor activity may regulate cell proliferation. The aim of the present work was to study the functional expression of these receptors in theca/interstitial cells (TIC).

METHODS

TIC were isolated by centrifugation in a Percoll gradient. P2Y receptors and cellular markers in TIC were detected by RT-PCR and Western blot. Intracellular calcium mobilization induced by purinergic drugs was evaluated by fluorescence microscopy, phosphorylation of MAPK p44/p42 and of cAMP response element binding protein (CREB) was determined by Western blot and proliferation was quantified by [3H]-thymidine incorporation into DNA.

RESULTS

RT-PCR showed expression of p2y2r and p2y6r transcripts, expression of the corresponding proteins was confirmed. UTP and UDP, agonists for P2Y2 and P2Y6 receptors, induced an intracellular calcium increase with a maximum of more than 400% and 200% of basal level, respectively. The response elicited by UTP had an EC50 of 3.5 +/- 1.01 microM, while that for UDP was 3.24 +/- 0.82 microM. To explore components of the pathway activated by these receptors, we evaluated the phosphorylation induced by UTP or UDP of MAPK p44 and p42. It was found that UTP increased MAPK phosphorylation by up to 550% with an EC50 of 3.34 +/- 0.92 and 1.41 +/- 0.67 microM, for p44 and p42, respectively; these increases were blocked by suramin. UDP also induced p44/p42 phosphorylation, but at high concentrations. Phosphorylation of p44/p42 was dependent on PKC and intracellular calcium. To explore possible roles of this pathway in cell physiology, cell proliferation and hCG-induced CREB-phosphorylation assays were performed; results showed that agonists increased cell proliferation and prevented CREB-phosphorylation.

CONCLUSION

Here, it is shown that UTP-sensitive P2Y receptors are expressed in cultured TIC and that these receptors had the ability to activate mitogenic signaling pathways and to promote cell proliferation, as well as to prevent CREB-phosphorylation by hCG. Regulation of TIC proliferation and steroidogenesis is relevant in ovarian pathophysiology since theca hyperplasia is involved in polycystic ovarian syndrome. Purinergic receptors described might represent an important new set of molecular therapeutic targets.