Role of the N, N′-dimethylbiguanide metformin in the treatment of female prepuberal BALB/c mice hyperandrogenized with dehydroepiandrosterone

Exploring the efficacy and mechanism of Bailing capsule to improve polycystic ovary syndrome in mice based on intestinal-derived LPS-TLR4 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Polycystic ovary syndrome (PCOS) is a common endocrine disorder associated with reproductive dysfunction and metabolic abnormalities, particularly characterized by insulin resistance and chronic low-grade inflammation. Multiple clinical studies have clearly demonstrated the significant efficacy and safety of the combination of Bailing capsules (BL) in the treatment of PCOS, but its pharmacological effects and mechanisms still require further study.

AIM OF THE STUDY

To evaluate the effect of BL on improving PCOS in mice and explore the mechanism.

METHODS

In this study, Dehydroepiandrosterone (DHEA) injection was administered alone and in combination with a high-fat and high-sugar diet to induce PCOS-like mouse. They were randomly divided into five groups: normal group (N), PCOS group (P), Bailing capsule low-dose group (BL-L), Bailing capsule high-dose group (BL-H) and Metformin + Daine-35 group (M + D). Firstly, the effects of BL on ovarian lesions, serum hormone levels, HOMA-IR, intestinal barrier function, inflammation levels, along with the expression of IRS1, PI3K, AKT, TLR4, Myd88, NF-κB p65, TNF-α, IL-6, and Occludin of the ovary, liver and colon were investigated. Finally, the composition of the gut microbiome of fecal was tested.

RESULTS

The administration of BL significantly reduced body weight, improved hormone levels, improved IR, and attenuated pathological damage to ovarian tissues, up-regulated the expression of IRS1, PI3K, and AKT in liver. It also decreased serum LPS, TNF-α, and IL-6 levels, while downregulating the expression of Myd88, TLR4, and NF-κB p65. Additionally, BL improved intestinal barrier damage and upregulated the expression of Occludin. Interestingly, the abundance of norank_f__Muribaculacea and Lactobacillus was down-regulated, while the abundance of Akkermansia was significantly up-regulated.

CONCLUSION

The results of the study showed that BL exerts a treatment PCOS effect, which may be related to the modulation of the gut microbiota, the improvement of insulin resistance and the intestinal-derived LPS-TLR4 inflammatory pathway. Our research will provide a theoretical basis for the clinical treatment of PCOS.

Transcription repression of estrogen receptor alpha by ghrelin/Gq/11/YAP signaling in granulosa cells promotes polycystic ovary syndrome

Polycystic ovarian syndrome (PCOS) is a prevalent endocrinological disorder affected by ghrelin. This study aimed to investigate the molecular mechanisms underlying the effects of ghrelin on PCOS manifestations in mice and to assess the therapeutic potential of ghrelin. Female C57BL/6 mice were subcutaneously injected with 6 mg/100 g dehydroepiandrosterone (DHEA) for 20 days to induce PCOS. Alterations in reproductive cycles, ovarian morphology, serum sex hormone levels, and related signaling markers were examined. Furthermore, ghrelin-induced effects on granulosa cells and the role of ghrelin/Gq/11/ Yes-associated protein (YAP) signaling were studied by silencing Gαq/11 or YAP using si-RNAs. Finally, we evaluated the therapeutic potential of anti-ghrelin antibodies in DHEA-induced PCOS mice. DHEA administration led to significant PCOS-associated changes including weight gain, disrupted estrous cycles, ovarian morphological alterations, and hormonal imbalances in mice, with elevated Gαq/11 and acylated ghrelin expression, which was also noted in PCOS patients. However, treatment with anti-ghrelin antibodies effectively managed DHEA-induced damage in PCOS mice. In vitro, ghrelin exposure resulted in granulosa cell injury and modulated estrogen receptors alpha (ERα) and YAP protein levels, whereas silencing YAP and Gαq/11 reversed ghrelin-induced detrimental effects and up-regulated ERα expression. This study revealed that DHEA-induced PCOS traits in mice could be improved by anti-ghrelin antibodies, with the ghrelin/Gq/11/YAP signaling pathway identified as a crucial mediator in granulosa cells, affecting ERα transcription to regulate PCOS. These findings suggest a potential therapeutic strategy for the treatment of PCOS.

Dehydroepiandrosterone with a high-fat diet treatment at inducing polycystic ovary syndrome in rat model

OBJECTIVE

This study aimed to evaluate the effects of dehydroepiandrosterone (DHEA) and DHEA combined with a high-fat diet (HFD) treatment of reproductive and endocrine metabolism in rats and then identify an ideal model of polycystic ovary syndrome (PCOS).

METHODS

Three-week-old female Sprague-Dawley rats were injected subcutaneously with DHEA or oil, fed with or without a HFD, for 21 days, during which body weight, feed intake, and estrous cycle monitoring were carried out. Fasting blood glucose was measured, and serum fasting insulin, testosterone, dihydrotestosterone (DHT), estradiol, progesterone, luteinizing hormone (LH), anti-Müllerian hormone (AMH), and follicle-stimulating hormone (FSH) were estimated by ELISA. Serum total cholesterol (TC), total triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were measured by colorimetric assay. Whereas, histologic changes in rat ovaries were evaluated by H&E staining. Ovarian steroid hormone synthases and their protein levels (StAR, 3β-HSD2, 17β-HSD1, CYP11A1, CYP17A1, and CYP19A1) were examined by Western blotting.

RESULTS

Both DHEA and DHEA + HFD-treated rats lost a regular estrous cycle; had polycystic ovarian changes, significantly higher serum fasting insulin and testosterone levels; and increased ovarian StAR, 3β-HSD2, and CYP11A1 protein levels. Additionally, rats in the DHEA + HFD-treated group were obese; had elevated fasting blood glucose, TG, DHT, AMH levels and LH:FSH ratios; increased ovarian 17β-HSD1 protein levels.

CONCLUSION

DHEA combined with HFD treatment is more effective at inducing PCOS than DHEA alone. The reproductive and endocrine metabolic aspects of this method are more consistent with the clinical characteristics of PCOS patients.

Etanercept Ameliorates Vascular, Endocrine, and Ovarian Changes in a Rat Model of DHEA-Induced Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a metabolic and endocrine disorder affecting women of reproductive age. This study examined the efficacy of etanercept (ETA), an anti-TNF-α drug, in alleviating endocrine, metabolic, and vascular dysfunction in a rat model of PCOS. Prepubertal female Wistar rats were divided into three groups: control, PCOS, and PCOS+ETA. The PCOS groups received dehydroepiandrosterone (DHEA) treatment, whereas the PCOS+ETA group received both DHEA and ETA. After 35 days, various biomarkers were evaluated, including systemic blood pressure, endothelial function, and eNOS and TNF-α expression levels in the thoracic aorta and ovaries. The PCOS group exhibited ovarian morphological changes, increased body weight, and hormonal imbalances, whereas the PCOS+ETA group showed restored levels of these parameters. Systemic blood pressure, urinary albumin levels, and protein excretion did not differ significantly differ among the groups. Endothelium-dependent relaxation, eNOS expression, TNF-α expression in the thoracic aorta, and TNF-α expression in the ovaries were restored to normal levels in the PCOS+ETA group. Furthermore, ovarian morphology was improved in the PCOS+ETA group. In conclusion, etanercept treatment shows promise in mitigating hormonal disturbances and vascular dysfunction in patients with PCOS, suggesting potential therapeutic advantages.

SGLT-2 inhibitors enhance the effect of metformin to ameliorate hormonal changes and inflammatory markers in a rat PCOS model

Polycystic ovary syndrome (PCOS) is a common endocrine, reproductive, and metabolic disorder affecting females. The management of PCOS is challenging and current interventions are not enough to deal with all consequences of this syndrome. We explored the beneficial effect of combined sodium glucose co transporter-2 inhibitor (SGLT-2i); (empagliflozin) and metformin on hormonal and metabolic parameters in an animal model of PCOS and insulin resistance (IR). Forty adult female Wistar rats divided into five groups: control, PCOS-IR, PCOS-IR treated with metformin, PCOS-IR treated with empagliflozin, and PCOS-IR treated with combined metformin and empagliflozin. Single modality treatment with metformin or empagliflozin yielded significant improvement in body mass index, insulin resistance, lipid profile, sex hormones, inflammatory markers, and ovarian cystic follicles. Combined metformin with empagliflozin expressed further significant improvement in sex hormones, inflammatory markers with disappearance of ovarian cystic follicles. The superior significant improvement with combined treatment over the single modality was in line with significant improvement in the ovarian AMPKα-SIRT1 expression.

Caffeic acid's role in mitigating polycystic ovary syndrome by countering apoptosis and ER stress triggered by oxidative stress

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder that affects women of reproductive age, characterized by androgen-induced oxidative stress leading to several metabolic disorders. In this study, we investigated the potential therapeutic effect of caffeic acid on PCOS and its underlying molecular mechanism. We used a human ovarian granulosa cell line (KGN cells) induced by hydrogen peroxide (H2O2) to examine how caffeic acid influences the protein expression of oxidative stress-induced apoptosis-related markers. Our results indicate that caffeic acid significantly inhibits intracellular reactive oxygen species (ROS) generation and safeguards KGN cells against oxidative stress. For the in vivo aspect of our study, female Sprague-Dawley (SD) rats were utilized to induce the PCOS model using dehydroepiandrosterone (DHEA). Caffeic acid was then administered to the rats for a duration of 6 weeks. The outcomes revealed that caffeic acid effectively improved irregular estrous cycles, fasting blood glucose levels, liver function, and lipid profiles in DHEA-induced PCOS rats. Additionally, it mitigated hyperandrogenism, enhanced steroidogenesis enzyme expression, and modulated apoptosis-related protein expression. Our findings strongly suggest that caffeic acid holds promising potential in reducing oxidative stress-induced damage and ameliorating PCOS-related complications by modulating ER stress.

Dehydroepiandrosterone supplementation and the impact of follicular fluid metabolome and cytokinome profiles in poor ovarian responders

BACKGROUND

Poor ovarian responders (POR) are women undergoing in-vitro fertilization who respond poorly to ovarian stimulation, resulting in the retrieval of lower number of oocytes, and subsequently lower pregnancy rates. The follicular fluid (FF) provides a crucial microenvironment for the proper development of follicles and oocytes through tightly controlled metabolism and cell signaling. Androgens such as dehydroepiandrosterone (DHEA) have been proposed to alter the POR follicular microenvironment, but the impact DHEA imposes on the FF metabolome and cytokine profiles is unknown. Therefore, the objective of this study is to profile and identify metabolomic changes in the FF with DHEA supplementation in POR patients.

METHODS

FF samples collected from 52 POR patients who underwent IVF with DHEA supplementation (DHEA +) and without (DHEA-; controls) were analyzed using untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) metabolomics and a large-scale multiplex suspension immunoassay covering 65 cytokines, chemokines and growth factors. Multivariate statistical modelling by partial least squares-discriminant regression (PLSR) analysis was performed for revealing metabolome-scale differences. Further, differential metabolite analysis between the two groups was performed by PLSR β-coefficient regression analysis and Student's t-test.

RESULTS

Untargeted metabolomics identified 118 FF metabolites of diverse chemistries and concentrations which spanned three orders of magnitude. They include metabolic products highly associated with ovarian function - amino acids for regulating pH and osmolarity, lipids such fatty acids and cholesterols for oocyte maturation, and glucocorticoids for ovarian steroidogenesis. Four metabolites, namely, glycerophosphocholine, linoleic acid, progesterone, and valine were significantly lower in DHEA + relative to DHEA- (p < 0.05-0.005). The area under the curves of progesterone glycerophosphocholine, linoleic acid and valine are 0.711, 0.730, 0.785 and 0.818 (p < 0.05-0.01). In DHEA + patients, progesterone positively correlated with IGF-1 (Pearson r: 0.6757, p < 0.01); glycerophosphocholine negatively correlated with AMH (Pearson r: -0.5815; p < 0.05); linoleic acid correlated with estradiol and IGF-1 (Pearson r: 0.7016 and 0.8203, respectively; p < 0.01 for both). In DHEA- patients, valine negatively correlated with serum-free testosterone (Pearson r: -0.8774; p < 0.0001). Using the large-scale immunoassay of 45 cytokines, we observed significantly lower MCP1, IFNγ, LIF and VEGF-D levels in DHEA + relative to DHEA.

CONCLUSIONS

In POR patients, DHEA supplementation altered the FF metabolome and cytokine profile. The identified four FF metabolites that significantly changed with DHEA may provide information for titrating and monitoring individual DHEA supplementation.

CXCL13 and CXCR5 are upregulated in PCOS mice ovaries but downregulated following metformin administration

Polycystic ovary syndrome (PCOS) is becoming a common pathology among women, yet its pathogenesis remains enigmatic. The chemokine C-X-C motif ligand 13 (CXCL13) and its receptor type 5 (CXCR5) regulate inflammatory responses but their roles in PCOS remain unknown. Metformin is commonly administered to PCOS patients but its mechanism of action remains unclear. Thus, we aimed to determine the expression of CXCL13 and CXCR5 in the ovaries of PCOS mice and to evaluate the therapeutic effect of metformin on them. The study comprised four groups of mice: control, PCOS, PCOS plus metformin, and PCOS plus vehicle. CXCL13 and CXCR5 were found to be elevated in the ovarian tissues of the PCOS mice. Metformin reduced ovarian CXCL13 and CXCR5 expressions in the PCOS mice. Hence, CXCL13 and CXCR5 are potentially involved in PCOS pathogenesis; and metformin may help alleviate the symptoms of PCOS by inhibiting CXCL13 expression and actions.

Partially purified non-polar phytocomponents from Aloe barbadensis Mill. gel restores metabolic and reproductive comorbidities in letrozole-induced polycystic ovary syndrome rodent model- an "in-vivo" study

ETHNOPHARMACOLOGICAL RELEVANCE

In India, Kumaryasava, a popular Aloe barbadensis Mill. gel preparation has therapeutic value in treatment of female reproductive disorders like menstrual disturbances and menopausal problems. Despite their widespread use, only a limited number of studies have probed into the scientific evidence for their varied bioactivities. In this regard, studies have demonstrated that Aloe vera gel has the potential to modulate steroidogenic activity in letrozole induced polycystic ovary syndrome (PCOS) rat. However, isolation and identification of the bioactive molecule/s from Aloe vera gel and studying their molecular targets will underpin the treatment regime for PCOS.

MATERIAL AND METHODS

The Partially Purified Non-Polar Phytocomponents (PPNPP)- LP1 and LP3 were isolated from the petroleum ether extract of Aloe vera gel by column chromatography. Based upon the GC-MS analysis, LP1 and LP3 comprised of n-Hexadecanoic acid and Campesterol acetate with an abundance of 97.07%, and 96.07% respectively. For evaluation of their bioactivities, eighty 3-4 months female Balb/c mice were classified as 10 groups with 8 animals in each group. Groups were control (C), PCOS (0.5 mg/kg/day Letrozole orally for 21days), PCOS treated orally for 60 days with Aloe vera gel (AVG) (10 mg/kg/day) (PCOS + AVG), PCOS treated orally for 60 days with petroleum ether extract (PE) of Aloe vera gel (25 μg/kg/day) (PCOS + PE), PCOS treated orally for 60 days with LP1 (0.5 μg/kg/day) (PCOS + LP1), PCOS treated orally for 60 days with commercially available pure compound-n-Hexadecanoic acid (HA) (0.5 μg/kg/day) (PCOS + HA), PCOS treated orally for 60 days with LP3 (0.01 μg/kg/day) (PCOS + LP3), PCOS treated orally for 60 days with commercially available pure compound- Campesterol acetate (CA) (0.01 μg/kg/day) (PCOS + CA), PCOS treated orally for 60 days with Metformin (100 mg/kg/day) (PCOS + Metformin) and PCOS treated orally for 60 days with DMSO (Vehicle) (PCOS + DMSO). Body weight, Oral glucose tolerance test, lipid profile, fasting glucose, insulin, estrus cycle, hormonal profile, gene expression of gonadotropin receptors (Fshr and Lhr), steroid receptors (Ar, Esr1, Esr2 and Pgr) and steroidogenic markers (Star, Hsd3b1, Cyp19a1 and Amh) were analysed in the ovaries. Polycystic ovarian morphology was assessed through histopathological changes of ovary. Toxicity markers- SGOT, SGPT and creatinine were also measured at the end of the study.

RESULTS

Mice treated with letrozole demonstrated significant increase in body weight, glucose intolerance, fasting insulin levels, HOMA-IR, triglycerides levels as well as testosterone levels, and a significant decline in the progesterone levels as compared to the control animals. PCOS animals also exhibited arrested estrus cyclicity, disrupted ovarian histopathology with the presence of multiple peripheral cysts and abnormal gene expression of gonadotropin receptor, steroid receptor and steroid markers. Oral administration of AVG, PE extract of AVG, LP3 and metformin greatly alleviated these complications in PCOS animals.

CONCLUSION

The above findings indicate the effectiveness of LP3, isolated from Aloe vera gel against letrozole induced PCOS in mice and may be used in the treatment of PCOS as an alternative to metformin.

Rhamnocitrin Attenuates Ovarian Fibrosis in Rats with Letrozole-Induced Experimental Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine-related cause of infertility in women and has an unknown etiology. Studies have shown that rhamnocitrin (Rha) exhibits positive effects on the reproductive system. This study investigated Rha's antifibrotic effects on PCOS rats and revealed its underlying mechanisms. Female SD rats were randomized into 4 groups (n = 8, each); the control group received tea oil by intraperitoneal injection and 1% w/v CMC by oral gavage; the PCOS group received letrozole (1 mg/kg); the PCOS+Rha group received letrozole and Rha (5 mg/kg); the PCOS+Met group received letrozole and Met (265 mg/kg) for 21 days. At the study end, Rha treatment restored letrozole-induced alterations in the relative ovarian weights, body weight, and relative weights of uterine and visceral adipose tissues. Histological observation showed that Rha ameliorates ovarian structure and fibrosis in PCOS. Administration of Rha reduced letrozole-induced metabolic dysfunction by ameliorating the levels of TC, TG, and HDL-C in the PCOS rats. Rha treatment also modulated the serum levels of sex hormones, which decreased T, E2, and LH and increased FSH in PCOS rats. In addition, Rha treatment modulated insulin resistance and increased gene expression of antioxidant enzymes (Cat, Sod2, Gpx3, Mgst1, Prdx3, Gsta4, Gsr, and Sod1) in the ovaries of the PCOS rats. Finally, Rha treatment appeared to increase the activity of PPAR-γ and inhibit the TGF-β1/Smad pathway in the ovaries of the PCOS rats. Our findings suggest that Rha significantly ameliorated metabolic disturbances and ovarian fibrosis in the PCOS rats. Rha perhaps is an effective compound for preventing ovarian fibrosis in the future.

Diacerein ameliorates letrozole-induced polycystic ovarian syndrome in rats

Polycystic ovary syndrome (PCOS) is the most common gynaecological endocrine disease that causes anovulatory infertility. The current study aimed to explore the possible role of diacerein (DIA), an IL-1β inhibitor, in treating letrozole-induced PCOS in rats that exhibit the metabolic and endocrinal criteria of PCOS patients. PCOS was induced in female Wistar rats by the oral administration of letrozole (1 mg/kg, per orally, p.o.) for 21 days. Rats were then treated with DIA (25 mg/kg/day, p.o.), DIA (50 mg/kg/day, p.o.), or metformin (2 mg/100 g/day, p.o.) for 14 days after the PCOS induction. PCOS resulted in a significantly higher body weight, ovarian weight, ovarian size, and cysts, as well as an elevation in serum testosterone, LH, insulin, glycemia, and lipid profile levels. All of these effects were significantly reduced by the DIA administration. Additionally, DIA remarkably inhibited the letrozole-induced oxidative stress in the ovaries, muscles, and liver by reducing the upraised levels of malondialdehyde and total nitrite and increasing the suppressed levels of superoxide dismutase and catalase. DIA enhanced the protective proteins Keap-1, Nrf2, and OH-1 levels. Finally, DIA inhibited the elevated mRNA levels of NLRP3 and caspase-1, the up-regulated inflammatory cytokines IL-6, TNF-α, and the IL-1β/NFκB signaling pathway. Our results proved that DIA ameliorates letrozole-induced PCOS through its antioxidant and anti-inflammatory properties.

A decrease in CD2 expression on NK cells is associated with PCOS but not influenced by metformin in a mouse model

Problem: Natural killer (NK) cells from the peripheral blood and spleen represent the source from which various tissues replenish their immune cell populations. Hyperandrogenism and high interleukin-2 (IL-2) levels are factors present in polycystic ovary syndrome (PCOS). These factors and metformin, one of the commonest medications used in treating PCOS, may have an impact on NK cell levels and its receptor profile. However, this is presently unknown. Here, we aimed to assess the levels of peripheral blood and splenic NK cells and their CD2 and CD94 expression patterns in a PCOS mouse model and test whether metformin could reverse these effects.

Method of study: Four mouse groups were designed as follows (n = 15/group): control, PCOS, PCOS plus vehicle, PCOS plus metformin. Dehydroepiandrosterone (DHEA) and a high-fat diet (HFD) were administered to induce the PCOS mouse model. Flow cytometry was used to analyze the expression of CD2 and CD94 on peripheral blood and splenic NK cells. Serum IL-2 levels were analyzed through enzyme-linked immunosorbent assays.

Results: PCOS mice had a decreased mean fluorescence intensity (MFI) of CD2 on peripheral blood NK cells and a decreased percentage of CD2+ splenic NK cells. Metformin administration did not significantly influence these changes; however, it reduced the splenic NK cell count. IL-2 levels were significantly elevated in PCOS mice and significantly reduced after metformin administration.

Conclusions: Our findings proved the association of PCOS with an altered expression of CD2 on peripheral blood and splenic NK cells and that of metformin with a lowered splenic NK cell reserve in PCOS conditions. These findings could further unlock key mechanisms in PCOS pathophysiology and in the mechanism of action of metformin, towards improving PCOS management.

The anti-androgenic effect of quercetin on hyperandrogenism and ovarian dysfunction induced in a dehydroepiandrosterone rat model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a multi-factorial endocrine disorder associated with hyperandrogenism. Dehydroepiandrosterone (DHEA) administration to prepubertal rats stimulates androgen biosynthesis and generation of the PCOS model. The present study aimed to evaluate the anti-androgenic effects of quercetin (Q) in comparison with metformin (MET) on hyperandrogenism and ovarian dysfunction in a DHEA-induced PCOS rat model. After induction of PCOS, female rats were allocated into six groups with 7 rats in each group: normal control; PCOS (DHEA), MET (25 mg/kg, oral administration), Q (25 mg/kg, oral administration), DHEA + MET (25 mg/kg, oral administration), and DHEA + Q (25 mg/kg, oral administration) for 28 days. MET and Q individually reduced body weight, serum free testosterone (T) and luteinizing hormone (LH), and LH/follicle-stimulating hormone (FSH) ratio in the PCOS rats. Both treatments elevated estradiol (E2) level, ovarian aromatase protein content, and E2/free T ratio in the PCOS rats. Additionally, MET and Q increased preantral, antral, and preovulatory follicles and corpora lutea counts, while both treatments decreased atretic follicle count and eliminated the formation of cysts in the PCOS rats. MET and Q reduced ovarian Bax and elevated Bcl-2 protein abundance in the PCOS rats. Our study revealed that Q is as effective as MET in reducing hyperandrogenism via decreasing free T level and improving hypothalamic-pituitary-ovarian axis function. The results suggest that MET and Q may enhance E2 concentration, ovarian aromatase protein content, folliculogenesis, and decrease atresia via attenuation of hyperandrogenism in PCOS rats.

Alpha/Beta Hydrolase Domain-Containing Protein 2 Regulates the Rhythm of Follicular Maturation and Estrous Stages of the Female Reproductive Cycle

Mammalian female fertility is defined by a successful and strictly periodic ovarian cycle, which is under the control of gonadotropins and steroid hormones, particularly progesterone and estrogen. The latter two are produced by the ovaries that are engaged in controlled follicular growth, maturation, and release of the eggs, i.e., ovulation. The steroid hormones regulate ovarian cycles via genomic signaling, by altering gene transcription and protein synthesis. However, despite this well-studied mechanism, steroid hormones can also signal via direct, non-genomic action, by binding to their membrane receptors. Here we show, that the recently discovered membrane progesterone receptor α/β hydrolase domain-containing protein 2 (ABHD2) is highly expressed in mammalian ovaries where the protein plays a novel regulatory role in follicle maturation and the sexual cycle of females. Ablation of Abhd2 caused a dysregulation of the estrous cycle rhythm with females showing shortened luteal stages while remaining in the estrus stage for a longer time. Interestingly, the ovaries of Abhd2 knockout (KO) females resemble polycystic ovary morphology (PCOM) with a high number of atretic antral follicles that could be rescued with injection of gonadotropins. Such a procedure also allowed Abhd2 KO females to ovulate a significantly increased number of mature and fertile eggs in comparison with their wild-type littermates. These results suggest a novel regulatory role of ABHD2 as an important factor in non-genomic steroid regulation of the female reproductive cycle.

Androgen receptor and uterine histoarchitecture in a PCOS rat model

Polycystic ovary syndrome (PCOS) is associated with hyperandrogenemia and uterine abnormalities. Our aim was to investigate the uterine effects of PCOS that are mediated through the androgen receptor (AR). After weaning, female rats were treated with sesame oil (Control), dehydroepiandrosterone (DHEA), or DHEA + flutamide (FLU, an AR antagonist) for 20 consecutive days. On postnatal day 41, serum, ovarian and uterine tissues were collected. DHEA and DHEA + FLU rats showed increased testosterone levels. DHEA rats showed increased epithelial height, glandular density, subepithelial stroma and myometrial thickness, associated with decreased nuclei density. These rats also showed increased uterine water content, with decreased aquaporin (AQP) 3, 7 and 8 expression in the uterine epithelium and increased AQP8 expression in the myometrium. DHEA rats also showed decreased uterine collagen remodeling, decreased cell proliferation in the subepithelial stroma, and increased apoptosis in the luminal and glandular epithelium and in the myometrium. They also showed an increase in insulin-like growth factor-1 and a decrease in phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase. The uterine stroma of DHEA rats showed no changes in progesterone receptor or estrogen receptor alpha (ERα) and increased AR expression. DHEA + FLU rats showed a smaller increase in the myometrial thickness, an increase in the uterine water content without AQP8 induction and a smaller decrease in collagen remodeling. These rats also showed no apoptosis induction and decreased proliferation in the myometrium, decreased ERα in the subepithelial stroma and myometrium and no modifications in AR. Our results demonstrate that the uterine cell turnover and collagen remodeling in DHEA rats are regulated through AR, directly or indirectly associated with ERα expression.

Korean Red Ginseng alleviates dehydroepiandrosterone-induced polycystic ovarian syndrome in rats via its antiinflammatory and antioxidant activities

BACKGROUND

Beneficial effects of Korean Red Ginseng (KRG) on polycystic ovarian syndrome (PCOS) remains unclear.

METHODS

We examined whether pretreatment (daily from 2 hours before PCOS induction) with KRG extract in water (KRGE; 75 and 150 mg/kg/day, p.o.) could exert a favorable effect in a dehydroepiandrosterone (DHEA)-induced PCOS rat model.

RESULTS

Pretreatment with KRGE significantly inhibited the elevation of body and ovary weights, the increase in number and size of ovarian cysts, and the elevation of serum testosterone and estradiol levels induced by DHEA. Pretreatment with KRGE also inhibited macrophage infiltration and enhanced mRNA expression levels of chemokines [interleukin (IL)-8, monocyte chemoattractant protein-1), proinflammatory cytokines (IL-1β, IL-6), and inducible nitric oxide synthase in ovaries induced by DHEA. It also prevented the reduction in mRNA expression of growth factors (epidermal growth factor, transforming growth factor-beta (EGF, TGF-β)) related to inhibition of the nuclear factor kappa-light-chain-enhancer of activated B cell pathway and stimulation of the nuclear factor erythroid-derived 2-related factor 2 pathway. Interestingly, KRGE or representative ginsenosides (Rb1, Rg1, and Rg3(s)) inhibited the activity of inflammatory enzymes cyclooxygenase-2 and iNOS, cytosolic p-IkB, and nuclear p-nuclear factor kappa-light-chain-enhancer of activated B in lipopolysaccharide-induced RAW264.7 cells, whereas they increased nuclear factor erythroid-derived 2-related factor 2 nuclear translocation.

CONCLUSION

These results provide that KRGE could prevent DHEA-induced PCOS via antiinflammatory and antioxidant activities. Thus, KRGE may be used in preventive and therapeutic strategies for PCOS-like symptoms.

Effect of Vitamin D3 on Mitochondrial Biogenesis in Granulosa Cells Derived from Polycystic Ovary Syndrome

Background

Polycystic ovary syndrome (PCOS) is an endocrine disorder diagnosed by anovulation hyperandro- genism. Hyperandrogenism increases apoptosis, which will eventually disturb follicular growth in PCOS patients. Since mitochondria regulate apoptosis, they might be affected by high incidence of follicular atresia. This may cause infertility. Since vitamin D3 has been shown to improve the PCOS symptoms, the aim of study was to investigate the effects vitamin D3 on mtDNA copy number, mitochondrial biogenesis, and membrane integrity of granulosa cells in a PCOS-induced mouse model.

Materials and Methods

In this experimental study, the PCOS mouse model was induced by dehydroepiandrosterone (DHEA). Granulosa cells after identification by follicle-stimulating hormone receptor (FSHR) were cultured in three groups: 1. granulosa cells treated with vitamin D3 (100 nM for 24 hours), 2. granulosa cells without any treatments, 3. Non-PCOS granulosa cells (control group). Mitochondrial biogenesis gene (TFAM) expression was compared between different groups using real-time PCR. mtDNA copy number was also investigated by qPCR. The mitochon- drial structure was evaluated by transmission electron microscopy (TEM). Hormonal levels were measured by an enzymelinked immunosorbent assay (ELISA) kit.

Results

The numbers of pre-antral and antral follicles increased in PCOS group in comparison with the non-PCOS group. Mitochondrial biogenesis genes were downregulated in granulosa cells of PCOS mice when compared to the non-PCOS granulosa cells. However, treatment with vitamin D3 increased mtDNA expression levels of these genes compared to PCOS granulosa cells with no treatments. Most of the mitochondria in the PCOS group were spherical with almost no cristae. Our results showed that in the PCOS group treated with vitamin D3, the mtDNA copy number increased significantly in comparison to PCOS granulosa cells with no treatments.

Conclusion

According to this study, we can conclude, vitamin D3 improves mitochondrial biogenesis and membrane integrity, mtDNA copy number in granulosa cells of PCOS mice which might improve follicular development and subsequently oocyte quality.

Hydroxysafflor yellow A exerts beneficial effects by restoring hormone secretion and alleviating oxidative stress in polycystic ovary syndrome mice

NEW FINDINGS

What is the central question of this study? What are the potential therapeutic roles of ginsenoside Rb1 and hydroxysafflor yellow A (HSYA) in polycystic ovary syndrome (PCOS). What is the main finding and its importance? HSYA restored the oestrous cycles of PCOS mice, reduced follicular cysts in ovaries and rescued abnormal hormone secretion; ginsenoside Rb1 did not ameliorate the main symptoms of PCOS mice. HSYA alleviated oxidative stress along with an enhancement of antioxidant enzyme activity. This highlights a potential role of HSYA in PCOS therapy.

ABSTRACT

Polycystic ovary syndrome (PCOS) is the most common endocrine disease resulting in female infertility. Hydroxysafflor yellow A (HSYA) and ginsenoside Rb1 have been shown to have antioxidant properties, but little is known about their impact in PCOS. Here dehydroepiandrosterone was used to induce PCOS in a mouse model that was characterized by an irregular oestrous cycle, cystic follicles and an elevated serum testosterone level. Supplementation of HSYA restored the oestrous cycle of PCOS mice, reduced follicular cysts in PCOS mouse ovaries and brought about a decline in serum testosterone level, while ginsenoside Rb1 did not ameliorate the above symptoms of PCOS mice. After HSYA treatment, there was elevation of serum oestradiol, progesterone, luteinizing hormone and anti-Müllerian hormone levels and a reduction of follicle-stimulating hormone level, but ginsenoside Rb1 only rescued the levels of follicle-stimulating hormone and anti-Müllerian hormone. Further analysis evidenced that HSYA reversed the expression of steroid hormone secretion-related genes Star, Hsd3b1, Cyp11a1 and Cyp19a1. In PCOS mice HSYA weakened the elevation of ovarian malondialdehyde, which is regarded as a biomarker for oxidative stress. Moreover, HSYA improved reduced glutathione content accompanied by a simultaneous increase in reduced to oxidized glutathione ratio, and enhanced the activities of the antioxidant enzymes superoxide dismutase, glutathione peroxidase and catalase. Collectively, HSYA exerted beneficial effects on PCOS mice by restoring hormone secretion and alleviating oxidative stress.

Phyllanthus muellerianus (Euphorbiaceae) Restores Ovarian Functions in Letrozole-Induced Polycystic Ovarian Syndrome in Rats

Polycystic ovarian syndrome (PCOS) is one of the common causes or female infertility. Phyllanthus muellerianus (Euphorbiaceae) is a plant used to treat various ailments including frequent menstruation and anovulation. We investigated the effects of P. muellerianus extracts on estrus cyclicity, lipid profile, oxidative stress-related markers, sex hormones, and ovarian architecture in letrozole-induced PCOS in rats. After induction of PCOS using letrozole (1 mg/kg/day), normal (n=6), and PCOS (n=108; distributed into 18 groups of 6 animals/group) rats were treated orally for 7 or 14 days with distilled water (10 ml/kg/day), clomiphene citrate (2 mg/kg/day), metformin (500 mg/kg/day), and aqueous or methanolic extract of P. muellerianus (30, 60, and 120 mg/kg). Estrus cyclicity, body, and sexual organ (ovaries and uterus) weights, biochemical and histological parameters were measured. There were letrozole-induced PCOS characterized by irregular estrus cyclicity, elevated (p<0.05-0.01) glycaemia, ovarian weight, triglycerides, total cholesterol, LDL cholesterol, VLDL cholesterol, malondialdehyde, luteinizing hormone (LH), and testosterone concentrations, but there were low (p<0.05-0.001) HDL cholesterol, estradiol, progesterone, catalase, peroxidase, and superoxide dismutase levels, compared with control. PCOS rats had multiple cysts compared with control. These reproductive, biochemical, and structural alterations were alleviated by P. muellerianus extracts. For instance, P. muellerianus restored the estrus cyclicity with a remarkable effect after 14 days of treatment. Moreover, P. muellerianus significantly decreased (p<0.001) LH and testosterone (both extracts; 30, 60, and 120 mg/kg) levels, but increased (p<0.01) estradiol (aqueous extract; 60 mg/kg) concentration. Cystic follicles were also decreased after plant application. P. muellerianus alleviated reproductive, hormonal, and structural alterations in PCOS rats. This plant could be useful in the management/treatment of reproductive and metabolic disorders related to PCOS.

Phosphodiesterase 4 inhibitor plus metformin is superior to metformin alone for the treatment of polycystic ovary syndrome: A rat model study

The role of metformin in the management of polycystic ovary syndrome (PCOS) and PCOS-related obesity remains controversial. Recent research on the treatment of PCOS-related obesity investigated novel therapeutic agents with the potential to work synergistically with metformin. The aim of the present study was to determine the synergistic effect of a phosphodiesterase 4 inhibitor (PDE4i) and metformin on weight and hormonal changes in a rat model of PCOS. A total of 40 female Sprague-Dawley rats were randomly divided into 4 groups (n=10/group): Sham; PCOS control (no medication after PCOS induction with dehydroepiandrosterone); metformin (300 mg/kg/day p.o. after PCOS induction); and metformin + PDE4i (300 mg/kg/day p.o. metformin + 0.5 mg/kg/day p.o. PDE4i after PCOS induction). The body weight was measured every 7 days, from day 1 to day 49. Vaginal smears were performed and examined daily via light microscopy for determination of the stage of each rat's estrous cycle. At the end of 21st day and at the end of the study, blood samples were collected from rats and the testosterone and insulin levels were measured. Immunohistochemical staining was performed to quantify phosphorylated cyclic AMP response element-binding protein expression in all groups. At the end of the study, the median body weight differed significantly among the groups (χ²=30.581, P<0.001), being the highest in the PCOS control group and the lowest in the metformin + PDE4i group. At the end of the study, the median testosterone level differed significantly among the groups (χ²=27.057, P<0.001), being the highest in the PCOS control group and the lowest in the metformin + PDE4i group. The cycle was restored to normal at the end of the study in all the rats in the metformin and metformin + PDE4i groups, whereas an irregular cycle persisted in all the rats in the PCOS control group. In conclusion, PDE4i + metformin was superior to metformin alone in reducing weight gain and decreasing the testosterone levels in a rat model of PCOS.

Effect of Hawthorn Leaf Flavonoids in Dehydroepiandrosterone-Induced Polycystic Ovary Syndrome in Rats

OBJECTIVE

To evaluate the potential beneficial effects of hawthorn leaf flavonoids (HLF) against polycystic ovary syndrome (PCOS) in a rat model of disease and elucidate the underlying molecular mechanism.

METHODS

The PCOS model was established by subcutaneous injection of dehydroepiandrosterone (DHEA, 60 mg/kg/day) for 21 consecutive days. HLF (200 mg/kg/day) were orally administered simultaneously or after the injection. The body weight was regularly monitored and recorded. The ovaries were weighed and histologically examined via hematoxylin and eosin staining. The number of follicular cysts was counted under a light microscope. The serous hormones were measured using enzyme-linked immunosorbent assay kits. Insulin resistance (IR) was calculated as HOMA-IR = fasting insulin (µU/L) × fasting glucose (mM)/22.5. The estrous cycle was determined by vaginal smear. The relative expression of tumor necrosis factor-α and interleukin-6 was measured by real-time polymerase chain reaction. The superoxide dismutase activity and malondialdehyde content was determined using commercially available kits.

RESULTS

DHEA induced a significant increase of body weight, ovary weight, number of follicular cysts, serous hormones, IR, inflammatory cytokines, and oxidative stress, and it also impaired the estrous cycle. Oral administration of HLF greatly alleviated these complications. Little toxicity of HLF was observed in our rat model.

CONCLUSION

HLF manifest protective effects against PCOS progression in the animal model, which may hold great promise for future clinical applications.

Glucose-regulated phosphorylation of TET2 by AMPK reveals a pathway linking diabetes to cancer

Diabetes is a complex metabolic syndrome that is characterized by prolonged high blood glucose levels and frequently associated with life-threatening complications^1,2. Epidemiological studies have suggested that diabetes is also linked to an increased risk of cancer^3-5. High glucose levels may be a prevailing factor that contributes to the link between diabetes and cancer, but little is known about the molecular basis of this link and how the high glucose state may drive genetic and/or epigenetic alterations that result in a cancer phenotype. Here we show that hyperglycaemic conditions have an adverse effect on the DNA 5-hydroxymethylome. We identify the tumour suppressor TET2 as a substrate of the AMP-activated kinase (AMPK), which phosphorylates TET2 at serine 99, thereby stabilizing the tumour suppressor. Increased glucose levels impede AMPK-mediated phosphorylation at serine 99, which results in the destabilization of TET2 followed by dysregulation of both 5-hydroxymethylcytosine (5hmC) and the tumour suppressive function of TET2 in vitro and in vivo. Treatment with the anti-diabetic drug metformin protects AMPK-mediated phosphorylation of serine 99, thereby increasing TET2 stability and 5hmC levels. These findings define a novel 'phospho-switch' that regulates TET2 stability and a regulatory pathway that links glucose and AMPK to TET2 and 5hmC, which connects diabetes to cancer. Our data also unravel an epigenetic pathway by which metformin mediates tumour suppression. Thus, this study presents a new model for how a pernicious environment can directly reprogram the epigenome towards an oncogenic state, offering a potential strategy for cancer prevention and treatment.

Vitamin D3 regulates steroidogenesis in granulosa cells through AMP-activated protein kinase (AMPK) activation in a mouse model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is an endocrine and metabolic disorder in reproductive-aged women. Hormonal abnormality caused by steroidogenesis disturbances appears to be the main culprit of the clinical picture in PCOS. Vitamin D3 could regulate steroidogenesis in granulosa cells, but the mechanism of action of vitamin D3 on steroidogenesis remains unknown. AMP-activated protein kinase (AMPK) has a modulating role in steroid hormone production. We investigated the effect of vitamin D3 on steroidogenesis in cultured granulosa cells of dehydroepiandrosterone-induced PCOS mice and studied the involvement of AMPK signalling pathway in the current process. Immunoblotting assay showed that vitamin D3 could increase phosphorylation of AMPK alpha and acetyl-CoA carboxylase, main substrate of AMPK. Vitamin D3 and 5-aminoimidazole-4-carboxamide-1-β-D-riboside or Aicar (AMPK activator) not only reduced gene expression of steroidogenic enzymes (P450scc or Cyp11a1, StAR, Cyp19a1 and 3B-HSD), but also reduced production of progesterone and 17B-estradiol assessed by radioimmunoassay. Pretreatment with compound C (AMPK inhibitor) decreased APMK phosphorylation and eliminated the effects of vitamin D3 and Aicar on steroidogenic enzymes expression and estradiol and progesterone production. This study showed that vitamin D3 has the main role in regulating of steroidogenesis in granulosa cells of mouse polycystic ovary through activation of the AMPK signalling pathway.

SIGNIFICANCE OF THE STUDY

Polycystic ovarian syndrome (PCOS) is an endocrine disorder of women in reproductive age. This disorder is partly related to disruption in steroidogenesis pathway and dysregulation of estradiol and progesterone production in granulosa cells of polycystic ovaries. Previously, we have shown that vitamin D3 could modulate steroidogenesis pathway in PCOS granulosa cells. In this study, we investigate the molecular mechanism of vitamin D3 in regulation of steroidogenesis pathway. We have shown that vitamin D3 has a modulating role in steroidogenesis pathway of granulosa cells by regulation of AMP-activated protein kinase (AMPK) as an underlying molecular mechanism in mouse polycystic ovary.

Dehydroepiandrosterone-induced activation of mTORC1 and inhibition of autophagy contribute to skeletal muscle insulin resistance in a mouse model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of reproductive age and also an important metabolic disorder associated with insulin resistance (IR). Hyperandrogenism is a key feature of PCOS. However, whether hyperandrogenism can cause IR in PCOS remains largely unknown. The mammalian target of rapamycin complex 1 (mTORC1) and its regulated autophagy are closely associated with IR. In the present study, we investigated the role of mTORC1-autophagy pathway in skeletal muscle IR in a dehydroepiandrosterone (DHEA)-induced PCOS mouse model. DHEA-treated mice exhibited whole-body and skeletal muscle IR, along with the activated mTORC1, repressed autophagy, impaired mitochondria, and reduced plasma membrane glucose transporter 4 (GLUT4) expression in skeletal muscle of the mice. In cultured C2C12 myotubes, treatment with high dose testosterone activated mTORC1, reduced autophagy, impaired mitochondria, decreased insulin-stimulated glucose uptake, and induced IR. Inhibition of mTORC1 or induction of autophagy restored mitochondrial function, up-regulated insulin-stimulated glucose uptake, and increased insulin sensitivity. On the contrary, inhibition of autophagy exacerbated testosterone-induced impairment. Our findings suggest that the mTORC1-autophagy pathway might contribute to androgen excess-induced skeletal muscle IR in prepubertal female mice by impairing mitochondrial function and reducing insulin-stimulated glucose uptake. These data would help understanding the role of hyperandrogenism and the underlying mechanism in the pathogenesis of skeletal muscle IR in PCOS.

Effects of vitamin D on ovary in DHEA-treated PCOS rat model: A light and electron microscopic study

AIM

The aim of this study was to investigate the effects of vitamin D treatment on ovary in experimentally designed polycystic ovary syndrome of female rats using light and electron microscopic techniques.

METHODS

Twenty-four female pre-pubertal rats were divided into control, DHEA and DHEA+Vit.D groups. In DHEA group, the PCOS rat model was developed by 6mg/kg/day dehydroepiandrosterone administration as subcutaneously injections. In DHEA+Vit.D group, 6 mg/kg/day DHEA and 120ng/100g/week 1,25(OH)2D3 was performed simultaneously. Controls were injected with vehicle alone. At the end of the 28 days, blood samples were collected and the ovarian tissues were taken for histological examinations.

RESULTS

FSH, LH levels, LH/FSH ratio, and testosterone levels showed a significant increase in DHEA group when compared with the control group. Moreover, these measurements were lower in the treatment group than the DHEA group. In DHEA group, increased number of atretic follicles and cystic follicles were seen with light microscopic analysis. Cystic follicles with attenuated granulosa cell layers and thickened theca cell layers and lipid accumulation in interstitial cells were observed by electron microscope. It is observed that atretic and cystic follicles were decreased as a result of vitamin D treatment.

CONCLUSION

Our results indicate the curative role of vitamin D treatment on the androgen excess in PCOS rat model which causes abnormalities in ovarian morphology and functions. Vitamin D has positive effects on the hormonal and structural changes observed in PCOS, but it has been concluded that long-term use may be more beneficial.

Assessment of growth and metabolism characteristics in offspring of dehydroepiandrosterone-induced polycystic ovary syndrome adults

Polycystic ovary syndrome (PCOS) is a common reproductive disorder that has many characteristic features including hyperandrogenemia, insulin resistance and obesity, which may have significant implications for pregnancy outcomes and long-term health of women. Daughters born to PCOS mothers constitute a high-risk group for metabolic and reproductive derangements, but no report has described potential growth and metabolic risk factors for such female offspring. Hence, we used a mouse model of dehydroepiandrosterone (DHEA)-induced PCOS to study the mechanisms underlying the pathology of PCOS by investigating the growth, developmental characteristics, metabolic indexes and expression profiles of key genes of offspring born to the models. We found that the average litter size was significantly smaller in the DHEA group, and female offspring had sustained higher body weight, increased body fat and triglyceride content in serum and liver; they also exhibited decreased energy expenditure, oxygen consumption and impaired glucose tolerance. Genes related to glucolipid metabolism such as Pparγ, Acot1/2, Fgf21, Pdk4 and Inhbb were upregulated in the liver of the offspring in DHEA group compared with those in controls, whereas Cyp17a1 expression was significantly decreased. However, the expression of these genes was not detected in male offspring. Our results show that female offspring in DHEA group exhibit perturbed growth and glucolipid metabolism that were not observed in male offspring.

Hyperandrogenemia Induced by Letrozole Treatment of Pubertal Female Mice Results in Hyperinsulinemia Prior to Weight Gain and Insulin Resistance

Women with polycystic ovary syndrome (PCOS) diagnosed with hyperandrogenism and ovulatory dysfunction have an increased risk of developing metabolic disorders, including type 2 diabetes and cardiovascular disease. We previously developed a model that uses letrozole to elevate endogenous testosterone levels in female mice. This model has hallmarks of PCOS, including hyperandrogenism, anovulation, and polycystic ovaries, as well as increased abdominal adiposity and glucose intolerance. In the current study, we further characterized the metabolic dysfunction that occurs after letrozole treatment to determine whether this model represents a PCOS-like metabolic phenotype. We focused on whether letrozole treatment results in altered pancreatic or liver function as well as insulin resistance. We also investigated whether hyperinsulinemia occurs secondary to weight gain and insulin resistance in this model or if it can occur independently. Our study demonstrated that letrozole-treated mice developed hyperinsulinemia after 1 week of treatment and without evidence of insulin resistance. After 2 weeks of letrozole treatment, mice became significantly heavier than placebo mice, demonstrating that weight gain was not required to develop hyperinsulinemia. After 5 weeks of letrozole treatment, mice exhibited blunted glucose-stimulated insulin secretion, insulin resistance, and impaired insulin-induced phosphorylation of AKT in skeletal muscle. Moreover, letrozole-treated mice exhibited dyslipidemia after 5 weeks of treatment but no evidence of hepatic disease. Our study demonstrated that the letrozole-induced PCOS mouse model exhibits multiple features of the metabolic dysregulation observed in obese, hyperandrogenic women with PCOS. This model will be useful for mechanistic studies investigating how hyperandrogenemia affects metabolism in females.

Impaired receptivity and decidualization in DHEA-induced PCOS mice

Polycystic ovary syndrome (PCOS), a complex endocrine disorder, is a leading cause of female infertility. An obvious reason for infertility in PCOS women is anovulation. However, success rate with high quality embryos selected by assisted reproduction techniques in PCOS patients still remain low with a high rate of early clinical pregnancy loss, suggesting a problem in uterine receptivity. Using a dehydroepiandrosterone-induced mouse model of PCOS, some potential causes of decreased fertility in PCOS patients were explored. In our study, ovulation problem also causes sterility in PCOS mice. After blastocysts from normal mice are transferred into uterine lumen of pseudopregnant PCOS mice, the rate of embryo implantation was reduced. In PCOS mouse uteri, the implantation-related genes are also dysregulated. Additionally, artificial decidualization is severely impaired in PCOS mice. The serum estrogen level is significantly higher in PCOS mice than vehicle control. The high level of estrogen and potentially impaired LIF-STAT3 pathway may lead to embryo implantation failure in PCOS mice. Although there are many studies about effects of PCOS on endometrium, both embryo transfer and artificial decidualization are applied to exclude the effects from ovulation and embryos in our study.

Dehydroepiandrosterone improves the ovarian reserve of women with diminished ovarian reserve and is a potential regulator of the immune response in the ovaries

Diminished ovarian reserve (DOR) has a high morbidity rate worldwide and has become a primary cause of infertility. DOR is a daunting obstacle in in vitro fertilization (IVF) and leads to poor ovarian response, high cancellation rates, poor IVF outcomes, and low pregnancy rates. Abnormal autoimmune function may also contribute to DOR. Dehydroepiandrosterone (DHEA) is a C19 androgenic steroid. DHEA is secreted mainly by the adrenal gland, and its secretion declines with age. DHEA has a pro-inflammatory immune function that opposes cortisol. The cortisol to DHEA ratio increases with age, which may lead to decreased immune function. DHEA supplementation helps improve this situation. A number of clinical case control studies and several prospective randomized clinical trials have observed a positive effect of DHEA supplementation in women with DOR. However, the underlying mechanism by which DHEA improves ovarian reserve remains unclear. DHEA functions as an immune regulator in many different tissues in mammals and may also play an important role in regulating the immune response in the ovaries. The conversion of DHEA to downstream sex steroids may allow it to regulate the immune response there. DHEA can also enhance the Th1 immune response and regulate the balance of the Th1/Th2 response. DHEA treatment can increase selective T lymphocyte infiltration in mice, resulting in a decline in the CD4+ T lymphocyte population and an upregulation of the CD8+ T lymphocyte population in ovarian tissue, thus regulating the balance of CD4+/CD8+ T cells. This review mainly focuses on how DHEA supplementation affects regulation of the immune response in the ovaries.

Early ovarian follicular development in prepubertal Wistar rats acutely exposed to androgens

Androgens may directly modulate early ovarian follicular development in preantral stages and androgen excess before puberty may disrupt this physiological process. Therefore, the aim of this study was to investigate the dynamics of follicular morphology and circulating androgen and estradiol levels in prepubertal Wistar rats acutely exposed to androgens. Prepubertal female Wistar rats were distributed into three groups: control, equine chorionic gonadotropin (eCG) intervention and eCG plus dehydroepiandrosterone (DHEA) intervention (eCG+DHEA). Serum DHEA, testosterone and estradiol levels were determined, and ovarian morphology and morphometry were assessed. The eCG+DHEA group presented increased serum estradiol and testosterone levels as compared with the control group (P<0.01), and higher serum DHEA concentration v. the eCG-only and control groups (P<0.01). In addition, the eCG+DHEA group had a higher number of, and larger-sized, primary and secondary follicles as compared with the control group (P<0.05). The eCG group presented intermediate values for number and size of primary and secondary follicles, without significant differences as compared with the other two groups. The number of antral follicles was higher in the eCG+DHEA and eCG groups v. controls (P<0.05). The number of primordial, atretic and cystic follicles were similar in all groups. In conclusion, the present experimental model using an acute eCG+DHEA intervention was useful to investigate events involved in initial follicular development under hyperandrogenic conditions, and could provide a reliable tool to study defective follicular development with possible deleterious reproductive consequences later in life.

High-fat diets exaggerate endocrine and metabolic phenotypes in a rat model of DHEA-induced PCOS

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder with unclear etiology and unsatisfactory management. Effects of diets on the phenotype of PCOS were not fully understood. In the present study, we applied 45 and 60% high-fat diets (HFDs) on a rat model of PCOS induced by postnatal DHEA injection. We found that both DHEA and DHEA+HFDs rats exhibited reproductive abnormalities, including hyperandrogenism, irregular cycles and polycystic ovaries. The addition of HFDs, especially 60% HFDs, exaggerated morphological changes of ovaries and a number of metabolic changes, including increased body weight and body fat content, impaired glucose tolerance and increased serum insulin levels. Results from qPCR showed that DHEA-induced increased expression of hypothalamic androgen receptor and LH receptor were reversed by the addition of 60% HFDs. In contrast, the ovarian expression of LH receptor and insulin receptor mRNA was upregulated only with the addition of 60% HFDs. These findings indicated that DHEA and DHEA+HFDs might influence PCOS phenotypes through distinct mechanisms: DHEA affects the normal function of hypothalamus-pituitary-ovarian axis through LH, whereas the addition of HFDs exaggerated endocrine and metabolic dysfunction through ovarian responses to insulin-related mechanisms. We concluded that the addition of HFDs yielded distinct phenotypes of DHEA-induced PCOS and could be used for studies on both reproductive and metabolic features of the syndrome.

A Dietary Medium-Chain Fatty Acid, Decanoic Acid, Inhibits Recruitment of Nur77 to the HSD3B2 Promoter In Vitro and Reverses Endocrine and Metabolic Abnormalities in a Rat Model of Polycystic Ovary Syndrome

Hyperandrogenism is the central feature of polycystic ovary syndrome (PCOS). Due to the intricate relationship between hyperandrogenism and insulin resistance in PCOS, 50%-70% of these patients also present with hyperinsulinemia. Metformin, an insulin sensitizer, has been used to reduce insulin resistance and improve fertility in women with PCOS. In previous work, we have noted that a dietary medium-chain fatty acid, decanoic acid (DA), improves glucose tolerance and lipid profile in a mouse model of diabetes. Here, we report for the first time that DA, like metformin, inhibits androgen biosynthesis in NCI-H295R steroidogenic cells by regulating the enzyme 3β-hydroxysteroid dehydrogenase/Δ5-Δ4-isomerase type 2 (HSD3B2). The inhibitory effect on HSD3B2 and androgen production required cAMP stimulation, suggesting a mechanistic action via the cAMP-stimulated pathway. Specifically, both DA and metformin reduced cAMP-enhanced recruitment of the orphan nuclear receptor Nur77 to the HSD3B2 promoter, coupled with decreased transcription and protein expression of HSD3B2. In a letrozole-induced PCOS rat model, treatment with DA or metformin reduced serum-free testosterone, lowered fasting insulin, and restored estrous cyclicity. In addition, DA treatment lowered serum total testosterone and decreased HSD3B2 protein expression in the adrenals and ovaries. We conclude that DA inhibits androgen biosynthesis via mechanisms resulting in the suppression of HSD3B2 expression, an effect consistently observed both in vitro and in vivo. The efficacy of DA in reversing the endocrine and metabolic abnormalities of the letrozole-induced PCOS rat model are promising, raising the possibility that diets including DA could be beneficial for the management of both hyperandrogenism and insulin resistance in PCOS.

The effect of androgens on ovarian follicle maturation: Dihydrotestosterone suppress FSH-stimulated granulosa cell proliferation by upregulating PPARγ-dependent PTEN expression

Intraovarian hyperandrogenism is one of the determining factors of follicular arrest in women with polycystic ovary syndrome (PCOS). Using androgenized rat models, we investigated the effects of androgens on metabolism, as well as on factors involved in follicular arrest and the reduced number of estrus cycles. The dihydrotestosterone (DHT)-treated rats had fewer estrus cycles, higher numbers of large arrested follicles and an increased in body weight gain compared with the dehydroepiandrostenedione (DHEA)- and placebo-treated rats. In cultured rat granulosa cells, DHT suppressed follicle stimulating hormone (FSH)-induced granulosa cell proliferation and increased the accumulation of cells in the G2/M phase. DHT decreased phosphorylated Akt (p-Akt) and cyclin D1 levels through increasing PTEN. DHT-promoted PTEN expression was regulated by peroxisome proliferator-activated receptor gamma (PPARγ) in granulosa cells. Meanwhile, in the large follicles of the DHT-treated rats, the expressions of PPARγ and PTEN were higher, but the expression of p-Akt and proliferating cell nuclear antigen (PCNA) were lower. Conclusively, DHT and DHEA produced differential effects on metabolism in prepubertal female rats like clinical manifestations of women with PCOS. DHT treatment may affect ovarian follicular maturation by altering granulosa cell proliferation through the regulation of enhancing PPARγ dependent PTEN/p-Akt expression in the granulosa cells.

High levels of testosterone inhibit ovarian follicle development by repressing the FSH signaling pathway

The effect of high concentrations of testosterone on ovarian follicle development was investigated. Primary follicles and granulosa cells were cultured in vitro in media supplemented with a testosterone concentration gradient. The combined effects of testosterone and follicle-stimulating hormone (FSH) on follicular growth and granulosa cell gonadotropin receptor mRNA expression were also investigated. Follicle growth in the presence of high testosterone concentrations was promoted at early stages (days 1-7), but inhibited at later stage (days 7-14) of in vitro culture. Interestingly, testosterone-induced follicle development arrest was rescued by treatment with high concentrations of FSH (400 mIU/mL). In addition, in cultured granulosa cells, high testosterone concentrations induced cell proliferation, and increased the mRNA expression level of FSH receptor (FSHR), and luteinized hormone/choriogonadotropin receptor. It was concluded that high concentrations of testosterone inhibited follicle development, most likely through regulation of the FSH signaling pathway, although independently from FSHR downregulation. These findings are an important step in further understanding the pathogenesis of polycystic ovary syndrome.

Effect of oral administration of low-dose follicle stimulating hormone on hyperandrogenized mice as a model of polycystic ovary syndrome

Background

Polycystic Ovary Syndrome (PCOS) is a widespread reproductive disorder characterized by a disruption of follicular growth and anovulatory infertility. In women with PCOS, follicular growth and ovulation can be induced by subcutaneous injections of low doses of follicle stimulating hormone (FSH). The aim of this study was to determine the effect of oral administration of recombinant human FSH (rhFSH) on follicle development in a PCOS murine model. Moreover, since it is unlikely that intact rhFSH is present into the circulation after oral administration, the biological activity of a peptide fragment, derived from the predicted enzymatic cleavage sites with the FSH molecule, was investigated in vitro on cumulus-enclosed oocytes (COCs).

Methods

Female peripubertal mice were injected with dehydroepiandrosterone (DHEA) diluted in sesame oil for 20 consecutive days and orally treated with a saline solution of rhFSH. A control group received only sesame oil and saline solution. At the end of treatments, blood was analyzed for hormone concentrations and ovaries were processed for morphological analysis. The presumptive bioactive peptide was added during in vitro maturation of bovine COCs and the effects on cumulus expansion and on maturation rate were evaluated.

Results

DHEA treatment increased serum levels of testosterone, estradiol and progesterone as well as the percentage of cystic follicles. Orally administered rhFSH restored estradiol level and reduced the percentage of cystic follicles. Despite these results indicating a reduction of the severity of PCOS in the mouse model, the presumptive bioactive peptide did not mimic the effect of rhFSH and failed to induce bovine cumulus expansion and oocyte maturation in vitro.

Conclusions

Although further studies are needed, the present data supports the concept that orally administrated FSH could attenuate some of the characteristic of PCOS in the mouse model.

Electronic supplementary material

The online version of this article (doi:10.1186/s13048-015-0192-9) contains supplementary material, which is available to authorized users.

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.

Impaired oocyte quality induced by dehydroepiandrosterone is partially rescued by metformin treatment

The present study evaluated the influence of hyperandrogenism on oocyte quality using a murine PCOS model induced by dehydroepiandrosterone (DHEA) and further explored the effect of metformin treatment. Female BALB/c mice were treated with a vehicle control or DHEA (6 mg /100 g body weight) or DHEA plus metformin (50 mg /100 g body weight) for 20 consecutive days. DHEA-induced mice resembled some characters of human PCOS, such as irregular sexual cycles and polycystic ovaries. After the model validation was completed, metaphase II (MII) oocytes were retrieved and subsequent analyses of oocyte quality were performed. DHEA-treated mice yielded fewer MII oocytes, which displayed decreased mtDNA copy number, ATP content, inner mitochondrial membrane potential, excessive oxidative stress and impaired embryo development competence compared with those in control mice. Metformin treatment partially attenuated those damages, as evidenced by the increased fertilization and blastocyst rate, ATP content, GSH concentration and GSH/GSSG ratio, and decreased reactive oxygen species levels. No significant difference in normal spindle assembly was observed among the three groups. During in vitro maturation (IVM), the periods of germinal vesicle breakdown (GVBD) and the first polar body (PB1) extrusion were extended and the maturation rate of GVBD oocytes was decreased in DHEA mice compared with controls. Metformin treatment decreased the time elapsed of GVBD while had no effect on PB1 extrusion. These results indicated that excessive androgen is detrimental to oocyte quality while metformin treatment is, directly or indirectly, beneficial for oocyte quality improvement.

High-fat diet induces significant metabolic disorders in a mouse model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common female endocrinopathy associated with both reproductive and metabolic disorders. Dehydroepiandrosterone (DHEA) is currently used to induce a PCOS mouse model. High-fat diet (HFD) has been shown to cause obesity and infertility in female mice. The possible effect of an HFD on the phenotype of DHEA-induced PCOS mice is unknown. The aim of the present study was to investigate both reproductive and metabolic features of DHEA-induced PCOS mice fed a normal chow or a 60% HFD. Prepubertal C57BL/6 mice (age 25 days) on the normal chow or an HFD were injected (s.c.) daily with the vehicle sesame oil or DHEA for 20 consecutive days. At the end of the experiment, both reproductive and metabolic characteristics were assessed. Our data show that an HFD did not affect the reproductive phenotype of DHEA-treated mice. The treatment of HFD, however, caused significant metabolic alterations in DHEA-treated mice, including obesity, glucose intolerance, dyslipidemia, and pronounced liver steatosis. These findings suggest that HFD induces distinct metabolic features in DHEA-induced PCOS mice. The combined DHEA and HFD treatment may thus serve as a means of studying the mechanisms involved in metabolic derangements of this syndrome, particularly in the high prevalence of hepatic steatosis in women with PCOS.

Characterization of reproductive, metabolic, and endocrine features of polycystic ovary syndrome in female hyperandrogenic mouse models

Polycystic ovary syndrome (PCOS) affects 5-10% of women of reproductive age, causing a range of reproductive, metabolic and endocrine defects including anovulation, infertility, hyperandrogenism, obesity, hyperinsulinism, and an increased risk of type 2 diabetes and cardiovascular disease. Hyperandrogenism is the most consistent feature of PCOS, but its etiology remains unknown, and ethical and logistic constraints limit definitive experimentation in humans to determine mechanisms involved. In this study, we provide the first comprehensive characterization of reproductive, endocrine, and metabolic PCOS traits in 4 distinct murine models of hyperandrogenism, comprising prenatal dihydrotestosterone (DHT, potent nonaromatizable androgen) treatment during days 16-18 of gestation, or long-term treatment (90 days from 21 days of age) with DHT, dehydroepiandrosterone (DHEA), or letrozole (aromatase inhibitor). Prenatal DHT-treated mature mice exhibited irregular estrous cycles, oligo-ovulation, reduced preantral follicle health, hepatic steatosis, and adipocyte hypertrophy, but lacked overall changes in body-fat composition. Long-term DHT treatment induced polycystic ovaries displaying unhealthy antral follicles (degenerate oocyte and/or > 10% pyknotic granulosa cells), as well as anovulation and acyclicity in mature (16-week-old) females. Long-term DHT also increased body and fat pad weights and induced adipocyte hypertrophy and hypercholesterolemia. Long-term letrozole-treated mice exhibited absent or irregular cycles, oligo-ovulation, polycystic ovaries containing hemorrhagic cysts atypical of PCOS, and displayed no metabolic features of PCOS. Long-term dehydroepiandrosterone treatment produced no PCOS features in mature mice. Our findings reveal that long-term DHT treatment replicated a breadth of ovarian, endocrine, and metabolic features of human PCOS and provides the best mouse model for experimental studies of PCOS pathogenesis.

Expression and activity of Rac1 is negatively affected in the dehydroepiandrosterone induced polycystic ovary of mouse

Background

Polycystic ovarian syndrome (PCOS) is characterized by the presence of multiple follicular cysts, giving rise to infertility due to anovulation. This syndrome affects about 10% of women, worldwide. The exact molecular mechanism leading to PCOS remains obscure. RhoGTPase has been associated with oogenesis, but its role in PCOS remains unexplored. Therefore, we attempted to elucidate the Vav-Rac1 signaling in PCOS mice model.

Methods

We generated a PCOS mice model by injecting dehydroepiandrosterone (DHEA) for a period of 20 days. The expression levels of Rac1, pRac1, Vav, pVav and Caveolin1 were analyzed by employing immuno-blotting and densitometry. The association between Vav and Rac1 proteins were studied by immuno-precipitation. Furthermore, we analyzed the activity of Rac1 and levels of inhibin B and 17β-estradiol in ovary using biochemical assays.

Results

The presence of multiple follicular cysts in ovary were confirmed by histology. The activity of Rac1 (GTP bound state) was significantly reduced in the PCOS ovary. Similarly, the expression levels of Rac1 and its phosphorylated form (pRac1) were decreased in PCOS in comparison to the sham ovary. The expression level and activity (phosphorylated form) of guanine nucleotide exchanger of Rac1, Vav, was moderately down-regulated. We observed comparatively increased expressions of Caveolin1, 17β-estradiol, and inhibin B in the polycystic ovary.

Conclusion

We conclude that hyperandrogenization (PCOS) by DHEA diminishes ovarian Rac1 and Vav expression and activity along with an increase in expression of Caveolin1. This is accompanied by an increase in the intra-ovarian level of '17 β-estradiol and inhibin B.

Oriental medicine Kyung-Ok-Ko prevents and alleviates dehydroepiandrosterone-induced polycystic ovarian syndrome in rats

Kyung-Ok-Ko (KOK), a traditional herbal prescription composed of Rehmannia glutinosa Liboschitz var. purpurae, Lycium chinense, Aquillaria agallocha, Poria cocos, Panax ginseng, and honey, has been widely used in traditional Oriental medicine as a vitalizing medicine or as the prescription for patients with age-associated disorders such as amnesia and stroke. However, the potential protective value of KOK for the treatment of polycystic ovarian syndrome (PCOS) is largely unknown. We investigated whether pre-administration (daily from 2 hours before PCOS induction) and post-administration (daily after induction of PCOS) of KOK (0.5, 1.0, and 2.0 g/kg/day, p.o.) could have a protective effect in a dehydroepiandrosterone (DHEA, s.c.)-induced PCOS rat model. Pre-administration of KOK significantly decreased the elevated body weight and ovary weight, elevated size and number of follicular cysts, elevated level of serum glucose, and estradiol after DHEA injection. KOK reduced the elevated percentage of CD8 (+) T lymphocytes in lymph nodes, the elevated mRNA expression of CD11b and CD3 in ovaries, and infiltration of macrophages in ovarian tissue with PCOS. KOK diminished the increased mRNA expression of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α), chemokines (IL-8, MCP-1), and iNOS in the ovaries, and increased the reduced mRNA expression of growth factors (EGF, TGF-β) by DHEA injection. Post-administration of KOK also improved the DHEA-induced PCOS-like symptoms, generally similar to those evident from pre-administration of KOK. KOK may effectively prevent and improve DHEA-induced PCOS via anti-inflammatory action, indicating its preventive and therapeutic potential for suppressing PCOS.

Mouse models to study polycystic ovary syndrome: a possible link between metabolism and ovarian function?

Polycystic ovary syndrome (PCOS) is the most common cause of female infertility affecting 6-8% of women worldwide. PCOS is characterized by two of the following three criteria: clinical or biochemical hyperandrogenism, oligo- or amenorrhea, and polycystic ovaries (PCO). In addition, women with PCOS are often obese and insulin resistant, and are at risk for type 2 diabetes and cardiovascular disease. The etiology of PCOS remains unknown. Therefore, several animal models for PCOS have been generated to gain insight into the etiology and development of the PCOS-associated phenotypes. Androgens are considered the main culprit of PCOS, and therefore, androgenization of animals is the most frequently used approach to induce symptoms that resemble PCOS. Prenatal or prepubertal androgen treatment results in many characteristics of human PCOS, including anovulation, cyst-like follicles, elevated luteinizing hormone (LH) levels, increased adiposity, and insulin insensitivity. However, PCOS has a heterogeneous presentation, and therefore it is difficult to generate a model that exactly reproduces the reproductive and metabolic phenotypes observed in women with PCOS. In this review, we discuss several mouse models for PCOS, and compare the reproductive and/or metabolic phenotypes observed in several androgen-induced models as well as in several genetic models.

The mechanism of mTOR (mammalian target of rapamycin) in a mouse model of polycystic ovary syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a common and complex endocrine disorder affecting 5-10% of women in reproductive age that is characterized by hyperandrogenism, oligo- or anovulation and infertility. However the pathophysiology of PCOS still remains unknown. The mammalian target of rapamycin (mTOR) is a central component that regulates various processes including cell growth, proliferation, metabolism, and angiogenesis. mTOR signaling cascade has recently been examined in ovarian follicles where it regulates granulosa cell proliferation and differentiation. mTOR functions as two complexes, mTOR complex 1 and 2. Therefore, we hypothesized that mTORC1 and/or 2 may have important role in proliferation of theca and granulosa cells in PCOS. In the present study, we sought to determine the mTOR signaling pathway in PCOS mouse ovary. We designed 3 groups: Control (C, no treatment), PCOS (P, The injection of DHEA (6 mg/100 g BW in 0.1 ml of sesame oil) (s.c) for 20 consecutive days), Vehicle (V, daily (s.c) sesame oil alone injection). Our results showed that mTORC1 and mTORC2-mediated signaling may play a role in PCOS mouse ovary. These findings provide evidence that mTORC1 and mTORC2 may have responsibility in increased ovarian follicular cell proliferation and growth in PCOS. Consequently, these results suggest that the mTOR signaling pathways (mTORC1 and mTORC 2) may create new clinical strategies to optimize developmental competence of PCOS should target correction of the entire follicle growth, oocyte development process and anovulatory infertility in PCOS.

Angiopoietins/TIE2 system and VEGF are involved in ovarian function in a DHEA rat model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrinological pathology among women of reproductive age. It is characterized by anovulation, oligo- or amenorrhea, hyperandrogenism, obesity, and insulin resistance. PCOS patients present with elevated levels of vascular endothelial growth factor (VEGF) in serum and follicular fluid. In this study, we examined the ovarian expression of angiopoietins (ANGPT) and their receptor tyrosine kinase receptor (TIE2), involved in the stabilization of blood vessels, in a rat model of dehydroepiandrosterone-induced PCOS. We also analyzed the effect of ovarian VEGF inhibition on ANGPT/TIE2, follicular development, and vascular stability. VEGF levels were increased in the PCOS ovaries, whereas the levels of its receptor fetal liver kinase-1 were decreased. In addition, the periendothelial cell area and the ANGPT1 to ANGPT2 ratio in the ovary were increased in the PCOS group. Percentage of primary follicles was increased and the percentage of preantral follicles and corpora lutea was decreased in the PCOS group. VEGF inhibition decreased the percentage of primary follicles close to control values. Interestingly, despite the presence of cysts in the ovaries from VEGF inhibitor-treated PCOS rats, its percentage was lower than the PCOS group without treatment. In summary, this study describes an alteration not only in the VEGF/fetal liver kinase-1 system but also in the ANGPT/TIE2 system in a dehydroepiandrosterone-induced PCOS rat model. This leads to an increase in periendothelial cell recruitment. We also demonstrated that ovarian VEGF inhibition can partially restore the accumulation of small follicles in PCOS rats and reduces cyst formation, improving ovulation and follicular development. Therefore, the inhibition of VEGF could be considered, in addition to other currently applied treatments, as a new strategy to be studied in PCOS patients to restore ovarian function.