Nitrophenols disrupt the expression and activity of biotransformation enzymes (CYP3A and COMT) in chicken ovarian follicles in vivo and in vitro.

Nitrophenols are environmental pollutants and xenobiotics, the main sources of which are diesel exhaust fumes and pesticides. The biotransformation processes that take place in the liver are defence mechanisms against xenobiotics, such as nitrophenols. Our previous study showed that the chicken ovary is an additional xenobiotic detoxification place and that nitrophenols disrupt steroidogenesis in chicken ovarian follicles. Therefore, the present study aimed to determine the in vivo and in vitro effects of 4-nitrophenol (PNP) and 3-methyl-4-nitrophenol (PNMC) on the expression and activity of phase I (CYP3A) and phase II (COMT) biotransformation enzymes in chicken ovary. In an in vivo study, hens were treated with a vehicle or 10 mg PNP or PNMC/kg b.wt. per day for 6 days. In an in vitro study, prehierarchical white and yellowish follicles, as well as the granulosa and theca layers of the three largest preovulatory follicles (F3, F2 and F1), were isolated and then incubated in a control medium or medium supplemented with PNP (10-6 M) or PNMC (10-6 M) for 24 or 48 h. Both in vivo and in vitro studies showed that nitrophenols exert tissue- and compound-dependent (PNP or PNMC) effects on CYP3A and COMT gene (real-time PCR) protein (Western blot) expression and their activity (colorimetric methods). The inhibitory effect of nitrophenols in vivo on the activity of biotransformation enzymes suggest that the ovary has the capacity to metabolise PNP and PNMC.

Short Culture of Bovine Hepatocytes Biopsied from Dairy Cows as a Model for Toxicological Studies-CYP 1A1 Activity Response to Zearalenone Treatment.

This study presents a simple and cost-effective method for isolating hepatocytes from liver biopsies obtained from healthy and ketotic dairy cows, which can be utilized for studying cellular metabolism, drug toxicity, and hepatocyte-specific gene function and regulation. The expression of hepatocyte marker genes (G6PC, ALB, CYP1A2) was measured and found to be highest at 6 h post-isolation, with a subsequent decrease over time. Cells isolated from ketotic livers exhibited lower expression levels than those from healthy livers. Furthermore, for the functional characterization of ketotic hepatocytes, the cells were exposed to varying doses of zearalenone (ZEA). While doses of 10-50 µM did not affect cell viability, the highest dose of ZEA (100 µM) significantly decreased cell viability, as measured using XTT assay. Additionally, the potential induction of cytochrome P450 A1 (CYP1A1) by ZEA was found. Despite limitations such as a short-term culture, this model provides a useful tool for conducting toxicological research.

Effects of Silver Nanoparticles on Proliferation and Apoptosis in Granulosa Cells of Chicken Preovulatory Follicles: An In Vitro Study.

The continuous development of poultry production related to the growing demand for eggs and chicken meat makes it necessary to use modern technologies. An answer to this demand may be the use of nanotechnology in poultry farming. One of the promising nanomaterials in this field are silver nanoparticles (AgNPs), which are used as disinfectants, reducing microbial pollution and the amounts of greenhouse gases released. This study aimed to evaluate the effect of AgNPs on the proliferation and apoptosis process in the granulosa cells of chicken preovulatory follicles. The in vitro culture experiment revealed that both 13 nm and 50 nm AgNPs inhibited the proliferation of the granulosa cells. However, a faster action was observed in 50 nm AgNPs than in 13 nm ones. A size-dependent effect of AgNP was also demonstrated for the caspase-3 activity. AgNPs 13 nm in size increased the caspase-3 activity in granulosa cells, while 50 nm AgNPs did not exert an effect, which may indicate the induction of distinct cell death pathways by AgNPs. In conclusion, our study reveals that AgNPs in vitro inhibit granulosa cell proliferation and stimulate their apoptosis. These results suggest that AgNPs may disrupt the final stage of preovulatory follicle maturation and ovulation.

Nitrophenols are negative modulators of steroidogenesis in preovulatory follicles of the hen (Gallus domesticus) ovary: An in vitro and in vivo study.

This study assessed the effects of 4-nitrophenol (PNP) and 3-methyl-4-nitrophenol (PNMC) on steroidogenesis in the granulosa layers (GLs) and theca layers (TLs) of chicken preovulatory follicles in vitro and in vivo. In the in vitro experiment, three of the largest yellow preovulatory follicles (F3 < F2 < F1) were exposed to PNP or PNMC (10-8-10-4 M), ovine luteinising hormone (oLH; 10 ng/mL), and combinations of oLH and PNP or PNMC (10-6 M). In the in vivo experiment, laying hens were treated for 6 days with PNP or PNMC (10 mg/kg). In vitro experiments revealed that PNP and PNMC decreased basal and oLH-stimulated P4 secretion from the GL as well as T and E2 secretion from the TLs of F3-F1 follicles. Treatment of laying hens with nitrophenols lowered plasma concentrations of luteinising hormone and all three steroids. The reduction of steroid secretion was associated with decrease in LHR, HSD3B1 and CYP19A1 mRNA expression in the GL and/or TLs of the preovulatory follicles, both in vitro and in vivo. Moreover, PNP decreased HSD3B protein expression in the GL of F2 follicles in vitro and in vivo, while PNMC diminished its expression in the GL of F1 follicles in vivo. In vitro, nitrophenols did not affect CYP19A1 protein expression; however, nitrophenols inhibited its expression in the TLs of F3 and F2 follicles in vivo. The results obtained clearly demonstrate that nitrophenols are negative modulators of steroidogenesis in chicken preovulatory follicles and, in consequence, may not only impair ovulation process, but also affect function of the hypothalamic-pituitary-ovarian axis.