Antimullerian hormone and its receptor gene expression in prenatally androgenized female rats

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.

Neonatal Exposure to Agonists and Antagonists of Sex Steroid Receptors Affects AMH and FSH Plasma Level and Their Receptors Expression in the Adult Pig Ovary

Simple Summary

The ovarian development and the establishment of ovarian reserve during fetal and/or neonatal life is critical for future reproductive success. Many environmental chemicals are known to negatively affect development and physiology of human and animal ovaries by interfering with endocrine systems, resulting in aberrant reproductive functions. The present study shows the long-term impact of neonatal exposure to agonists and antagonists of sex steroid receptors on AMH and FSH signalling in the ovary of adult pigs. Our findings suggest alteration in ovarian follicle recruitment from ovarian reserve arising from neonatal disruption of androgen/estrogen signalling induced by environmental endocrine active compounds. Everyday use of many endocrine disruptors is already prohibited after their harmful impacts on normal physiology have become known. Nevertheless, market introduction of new chemicals with potential deleterious influence on reproductive physiology has continued. Our outcomes confirm that a neonatal window plays an essential role in the physiological programming of ovarian function in adult pigs. The influence of environmental chemicals on this critical neonatal window needs to be investigated in order to gain a comprehensive view of deleterious interactions between endocrine disrupting chemicals and ovarian function.

Abstract

In this study piglets were injected with testosterone propionate (TP, an androgen), flutamide (FLU, an antiandrogen), 4-tert-octylphenol (OP, an estrogenic compound), ICI 182,780 (ICI, an antiestrogen) or corn oil (controls) between postnatal days 1 and 10 (N = 5/group). Then plasma anti-Müllerian hormone (AMH) and follicle stimulating hormone (FSH) concentration and the expression of their receptors were examined in the adult pig ovary. TP and FLU decreased plasma AMH and FSH concentration. In preantral follicles, TP resulted in upregulation of AMHR2 and FSHR expression, but decreased AMH protein abundance. FLU upregulated AMHR2 expression, while OP increased FSHR mRNA. In small antral follicles, OP upregulated ACVR1 and BMPR1A expression, while FLU increased BMPR1A mRNA. FLU and ICI resulted in upregulation of AMHR2 expression. TP and FLU upregulated AMH expression, while it was downregulated in response to OP or ICI. Moreover, OP and ICI resulted in downregulation of FSHR expression, while FLU decreased FSHR protein abundance. In conclusion, neonatal exposure to either agonist or antagonist of androgen receptor affected AMH and FSH signalling systems in preantral follicles. In small antral follicles these systems were influenced by compounds with estrogenic, antiestrogenic, and antiandrogenic activity. Consequently, these hormonal agents may cause an accelerated recruitment of primordial follicles and affect the cycling recruitment of small antral follicles in pigs.

Hypomethylation of specific CpG sites in the promoter region of steroidogeneic genes (GATA6 and StAR) in prenatally androgenized rats

INTRODUCTION

The methylation level of promoters is one of the most studied and well-known epigenetic mechanisms that programs the amount of gene expression. Over expression of steroidogenesis genes via epigenetic control can result in hypetandrogenism, which is the main endocrine aspect of polycystic ovarian syndrome (PCOS).

AIMS

In the present study we aimed to determine and compare the promoter methylation levels of three steroidogenic genes, CYP17, GATA6 and StAR, in theca cells of prenatally androgenized (PNA) rats to those of controls.

MATERIALS AND METHODS

Pregnant Wistar rats in the PNA group received 5 mg free testosterone, dissolved in 500 ml solvent, subcutaneously injected on day 20 of pregnancy, while controls were injected with 500 ml of solvent only. Theca cell samples, taken from the ovaries of eight to ten female offspring of both the PNA and control groups, were measured for promoter methylation levels of the aforementioned genes, using the bisulfite sequence PCR (BSP) method.

KEY FINDINGS

Although the promoters of all three genes were slightly hypomethylated in the PNA group, the differences observed were not significant compared to the control group. The methylation of -520 and -822 positions, in the GATA6 and the StAR promoter respectively, were significantly decreased in the PNA group.

SIGNIFICANCES

The results of this study suggest that alterations in the steroidogenesis pathway after exposure to excess androgen may be a result of changes in the pattern of the methylation of the relevant genes.