ABSTRACT
To assess the effects of 4-nitrophenol (PNP) and 3-methyl-4-nitrophenol (PNMC) on steroidogenesis in the chicken ovary, white (WF, 1-4 mm) and yellowish (YF, 4-8 mm) prehierarchical follicles were incubated in a medium supplemented with PNP or PNMC (10-8-10-4 M), ovine LH (oLH; 10 ng/mL), and combinations of oLH with PNP or PNMC (10-6 M). Testosterone (T) and estradiol (E2) concentrations in media and mRNA expression for steroidogenic proteins (STAR, HSD3B1, and CYP19A1), and LH receptors (LHR), estrogen receptor α (ESR1) and ß (ESR2) in follicles were determined by RIA and real-time qPCR, respectively. PNP and PNMC decreased T and E2 secretion by the WF and YF, and oLH-stimulated T secretion from these follicles. PNP decreased basal STAR and HSD3B1 mRNA levels both in the WF and YF, and CYP19A1 mRNAs in the WF. PNP reduced oLH-affected mRNA expression of these genes in the YF. PNMC inhibited basal STAR, HSD3B1, and CYP19A1 mRNA expression in the WF, but not in the YF. PNMC reduced oLH-stimulated STAR and CYP19A1 expression in the YF and WF, respectively. PNP decreased basal mRNA expression of LHR, ESR1, and ESR2 in the WF, but it increased ESR1 and ESR2 mRNA levels in the YF. PNMC reduced both basal and oLH-affected LHR, ESR1, and ESR2 mRNA expression in the WF; however, it did not influence expression of these genes in the YF. We suggest that nitrophenols by influencing sex steroid synthesis and transcription of LH and estrogen receptors in prehierarchical ovarian follicles may impair their development and selection to the preovulatory hierarchy.
Subject(s)
Aromatase/metabolism , Chickens , Gene Expression Regulation/drug effects , Multienzyme Complexes/metabolism , Nitrophenols/pharmacology , Ovarian Follicle , Progesterone Reductase/metabolism , Steroid Isomerases/metabolism , Animals , Aromatase/genetics , Down-Regulation , Estrogen Receptor alpha/genetics , Estrogen Receptor alpha/metabolism , Female , Multienzyme Complexes/genetics , Phosphoproteins/genetics , Phosphoproteins/metabolism , Progesterone Reductase/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, LH/genetics , Receptors, LH/metabolism , Steroid Isomerases/genetics , Tissue Culture TechniquesABSTRACT
This study aimed to examine the mRNA expression, activity, and immunolocalisation of apoptosis/proliferation regulating factors following in vitro exposure of the stroma, white (WFs), and yellowish (YFs) follicles of the chicken ovary to 4-nitrophenol (PNP) or 3-methyl-4-nitrophenol (PNMC). PNMC increased the mRNA expression of caspase-3, -8, Apaf-1, and cytochrome c in the ovarian stroma. The activity of caspase-3, -8, and -9 decreased in WFs in both nitrophenol-treated groups. PNP reduced the number of caspase-3-positive cells in the stromal connective tissue (CT) and the theca interna and externa layers of WFs. In the stroma, the proliferating index decreased in the wall of primary follicles in both nitrophenol-treated groups, however, in the CT, the effect of PNMC was opposite. In the theca interna of WFs, PNP diminished the proliferating index. These results suggest that nitrophenols might impact the development of chicken ovarian follicles by affecting cell death and proliferation.
