Peroxisome proliferator-activated receptor gamma and early folliculogenesis during an acute hyperandrogenism condition

Upregulation of Cyp19a1 and PPAR-γ in ovarian steroidogenic pathway by Ficus religiosa: A potential cure for polycystic ovary syndrome

ETHNOPHARMACOLOGICAL RELEVANCE

Quite a few plants are in use to treat female infertility and associated problems. Availing the cues from traditional knowledge, phytochemical studies and ethnopharmacological evidences, the aphrodisiac plant Ficus religiosa (F. religiosa) is widely in use to cure infertility in women. For instance, the juice of leaf and aerial root of F. religiosa is reported to normalize the dysregulated menstrual cycle in women. Besides, it is believed that regular circumambulation of F. religiosa during the early hours of the morning helps women in alleviating infertility which could be attributed to the potential phytovolatiles released from F. religiosa. However, the evidences for therapeutic potential of F. religiosa in treating female infertility are arbitrary and mostly anecdotal.

AIM OF THE STUDY

The present study was aimed at examining if extracts of fresh and/or dry leaf of F. religiosa would cure polycystic ovary syndrome (PCOS) in the rat model.

METHODS

Rats were divided into seven groups; control (Group I), PCOS-induced (P.O, Letrozole -1 mg/kg BW for 21 days) and untreated (Group II), PCOS-induced and treated with the leaf extracts of F. religiosa (Groups III-VI), and, PCOS-induced and treated with pioglitazone (Group VII). The estrous intervals, body and organ weights (ovary and uterus), and serum hormones (testosterone, luteinizing hormone [LH], estrogen, and progesterone) were measured, and the expression of Cyp19a1 (aromatase), and Peroxisome Proliferator-Activated Receptor-γ (PPAR-γ) were assessed in the experimental rats. The levels of 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β-hydroxysteroid dehydrogenase (17β-HSD), and antioxidants (MDA, GSH, GPx, SOD, and CAT) were also quantified. Besides, the putative volatile compounds in the esterified leaf extracts were identified using Gas Chromatography-Mass Spectrometry (GC-MS).

RESULTS

Letrozole treatment induced irregular estrous and altered weight of organs and hormonal milieu, which were reverted to normal in leaf extracts-treated PCOS-induced rats. Remarkably, fresh leaf treatment up-regulated Cyp19a1and PPAR-γ and increased the levels of 3β-HSD and 17β-HSD. We found 3-acetoxy-3-hydroxy-propionic acid in fresh and dry leaf extracts, which we attribute to efficacy of the extracts in alleviating PCOS.

CONCLUSION

Put together, our findings suggest the leaves of F. religiosa as potential in alleviating PCOS, mainly due to the presence of putative volatile molecules. Further screening of the leaves of F. religiosa is recommended to identify other key molecules and to develop a systematic therapeutic intervention for PCOS.

Fetal programming by androgen excess in rats affects ovarian fuel sensors and steroidogenesis

Fetal programming by androgen excess is hypothesized as one of the main factors contributing to the development of polycystic ovary syndrome (PCOS). PCOS is more than a reproductive disorder, as women with PCOS also show metabolic and other endocrine alterations. Since both ovarian and reproductive functions depend on energy balance, the alterations in metabolism may be related to reproductive alterations. The present study aimed to evaluate the effect of androgen excess during prenatal life on ovarian fuel sensors and its consequences on steroidogenesis. To this end, pregnant rats were hyperandrogenized with testosterone and the following parameters were evaluated in their female offspring: follicular development, PPARG levels, adipokines (including leptin, adiponectin, and chemerin as ovarian fuel sensors), serum gonadotropins (LH and FSH), the mRNA of their ovarian receptors, and the expression of steroidogenic mediators. At 60 days of age, the prenatally hyperandrogenized (PH) female offspring displayed both an irregular ovulatory phenotype and an anovulatory phenotype with altered follicular development and the presence of cysts. Both PH groups showed altered levels of both proteins and mRNA of PPARG and a different expression pattern of the adipokines studied. Although serum gonadotropins were not impaired, there were alterations in the mRNA levels of their ovarian receptors. The steroidogenic mediators Star, Cyp11a1, Cyp17a1, and Cyp19a1 were altered differently in each of the PH groups. We concluded that androgen excess during prenatal life leads to developmental programming effects that affect ovarian fuel sensors and steroidogenesis in a phenotype-specific way.

Effect of hyperandrogenism on ovarian function

The objective of this work was to study the ovarian function when follicular development is induced during a hyperandrogenic condition. Female rats were injected with either equine chorionic gonadotropin (eCG group) to induce folliculogenesis or eCG together with DHEA to induce folliculogenesis in a hyperandrogenic condition (eCG+HA group). The control group was injected with vehicle. Ovarian mRNA levels of the peroxisome proliferator-activated receptor gamma (PPARγ) co-activator PGC1α, the PPARγ co-repressor NCoR, the main enzymes involved in the ovarian steroidogenesis (CYP17, 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β-HSD, and CYP19A), and cyclooxygenase 2 (COX2) were evaluated only by real-time PCR. COX2 was evaluated by both real-time PCR and western blot. Serum steroid hormones and both the oxidative and inflammatory statuses were also quantified. We found that eCG-induced folliculogenesis induced increased mRNA levels of PGC1α and decreased those of NCoR when compared with controls. In addition, we found an increase in serum estradiol (E2) levels and enhanced mRNA expression of CYP19A. A pro-inflammatory status and a pro-oxidant status were also established. When folliculogenesis was induced in a hyperandrogenic condition, the mRNA levels of the PPARγ co-repressor NCoR remained higher than in controls and the pro-inflammatory and pro-oxidant statuses were enhanced. In addition, the enzymes involved in ovarian steroidogenesis were altered leading to the accumulation of testosterone and an unfavorable E2/testosterone ratio. These alterations led to abnormal follicular development.

Prenatal hyperandrogenization induces metabolic and endocrine alterations which depend on the levels of testosterone exposure

Prenatal hyperandrogenism is able to induce polycystic ovary syndrome (PCOS) in rats. The aim of the present study was to establish if the levels of prenatal testosterone may determine the extent of metabolic and endocrine alterations during the adult life. Pregnant Sprague Dawley rats were prenatally injected with either 2 or 5 mg free testosterone (groups T2 and T5 respectively) from day 16 to day 19 day of gestation. Female offspring from T2 and T5 displayed different phenotype of PCOS during adult life. Offspring from T2 showed hyperandrogenism, ovarian cysts and ovulatory cycles whereas those from T5 displayed hyperandrogenism, ovarian cysts and anovulatory cycles. Both group showed increased circulating glucose levels after the intraperitoneal glucose tolerance test (IPGTT; an evaluation of insulin resistance). IPGTT was higher in T5 rats and directly correlated with body weight at prepubertal age. However, the decrease in the body weight at prepubertal age was compensated during adult life. Although both groups showed enhanced ovarian steroidogenesis, it appears that the molecular mechanisms involved were different. The higher dose of testosterone enhanced the expression of both the protein that regulates cholesterol availability (the steroidogenic acute regulatory protein (StAR)) and the protein expression of the transcriptional factor: peroxisome proliferator-activated receptor gamma (PPAR gamma). Prenatal hyperandrogenization induced an anti-oxidant response that prevented a possible pro-oxidant status. The higher dose of testosterone induced a pro-inflammatory state in ovarian tissue mediated by increased levels of prostaglandin E (PG) and the protein expression of cyclooxygenase 2 (COX2, the limiting enzyme of PGs synthesis). In summary, our data show that the levels of testosterone prenatally injected modulate the uterine environment and that this, in turn, would be responsible for the endocrine and metabolic abnormalities and the phenotype of PCOS during the adult life.