The effect of ZnO nanoparticles on rabbit spermatozoa motility and viability parameters in vitro.

Zinc plays a very important role in various biological activities of the body. Multifaceted role of zinc is also known in testes development, spermatogenesis, capacitation and has effect on spermatozoa motility. On the other hand, the growing industry of nanotechnology has created reasonable interest of the risk assessment for nanoparticles. The aim of this study was to evaluate in vitro effect of zinc oxide (ZnO) nanoparticles on rabbit spermatozoa. Fresh semen was collected from sexually mature New Zealand rabbits. Experimental groups were prepared by diluting semen with ZnO nanoparticles in seven different concentrations (6-391 mg/mL). The experimental groups were compared with control group. Semen was assessed using computer assisted semen analysis (CASA) at intervals of 0, 1, 2 and 3 h of incubation. The mitochondrial toxicity assay (MTT) assay was used to determine cell viability. The results of monitored motility parameters in experimental groups showed a decreasing trend during whole experiment. Significant decrease (P < 0.001) of motility and progressive motility was observed after 3 h of incubation in samples cultured with higher ZnO nanoparticles in comparison to the control group. After 3 h of incubation, viability of rabbit spermatozoa showed slightly increased values in group with the lowest concentration of ZnO nanoparticles, but in other groups viability showed non-significant decrease compared to control. Similar tendency was detected for spermatozoa membrane integrity. These original data show the negative dose-dependent effect of ZnO nanoparticles on spermatozoa motility and viability parameters.

Effects of PCB 126 and PCB 153 on secretion of steroid hormones and mRNA expression of steroidogenic genes (STAR, HSD3B, CYP19A1) and estrogen receptors (ERα, ERß) in prehierarchical chicken ovarian follicles.

The objective of this study was to assess the in vitro effects of dioxin-like PCB 126 and non-dioxin-like PCB 153 on basal and ovine LH (oLH)-stimulated testosterone (T) and estradiol (E2) secretion and expression of steroidogenic genes (STAR, HSD3B and CYP19A1) and estrogen receptors α (ERα) and ß (ERß) in white (WF) and yellowish (YF) prehierarchical follicles of the hen ovary. Steroid concentrations in a medium and gene expression in follicles following 6h of exposition were determined by RIA and real-time qPCR, respectively. Both PCBs increased basal and oLH-stimulated T secretion by the WF follicles. PCB 126 reduced basal E2 secretion by the WF follicles. PCB 153 elevated but PCB 126 reduced oLH-stimulated E2 secretion by the prehierarchical follicles. PCB 126 increased basal STAR and HSD3B and reduced CYP19A1 mRNA expression in these follicles. PCB 153 increased basal expression of STAR and HSD3B in YF follicles, but diminished HSD3B mRNA levels in the WF. The studied PCBs had an opposite effect on basal and oLH-stimulated CYP19A1 mRNA expression in prehierarchical follicles. Both PCBs modulated basal and inhibited oLH-stimulated ERα and ERß gene expression in the prehierarchical follicles. In conclusion, data of the current study demonstrate the congener-specific effects of PCBs on sex steroid secretion by prehierarchical follicles of the chicken ovary, which are at least partly related to STAR, HSD3B and CYP19A1 gene expression. It is suggested that PCBs, by influencing follicular steroidogenesis and expression of estrogen receptors, may impair development and selection of yellowish follicles to the preovulatory hierarchy.

Effect of PCB 126 on aryl hydrocarbon receptor 1 (AHR1) and AHR1 nuclear translocator 1 (ARNT1) mRNA expression and CYP1 monooxygenase activity in chicken (Gallus domesticus) ovarian follicles.

The aim of the experiment was to study the in vitro effect of 3,3',4,4',5-pentachlorobiphenyl (PCB 126; a coplanar PCB congener) on aryl hydrocarbon receptor (AHR1) and AHR1 nuclear translocator (ARNT1) mRNA expression and the activity of CYP1 family monooxygenases in chicken ovarian follicles. White (1-4 mm) and yellowish (4-8 mm) prehierarchical follicles as well as fragments of the theca and granulosa layers of the 3 largest preovulatory follicles (F3-F1) were incubated in a medium supplemented with 0 (control group), 1, 10 or 100 nM PCB 126. The incubation was carried out for 6 h or 24 h for determination of mRNA expression of AHR1 and ARNT1 genes (real-time qPCR) and CYP1 monooxygenase activity (EROD and MROD fluorometric assays), respectively. It was found that chicken ovarian follicles express mRNA of AHR1 and ARNT1 genes. A modulatory effect of PCB 126 on AHR1 and ARNT1 expression depended not only on the biphenyl concentration but also on the follicular layer and the maturational state of the follicle. EROD and MROD activities appeared predominantly in the granulosa layer of the yellow preovulatory follicles. PCB 126 induced these activities in a dose-dependent manner in all ovarian follicles. The obtained results suggest that ovarian follicles, especially the granulosa layer, are involved in the detoxification process of PCBs in the laying hen. Taking this finding into consideration it can be suggested that the granulosa layer of the yellow hierarchical follicles plays a key role in the protective mechanism which reduces the amount of transferred dioxin-like compounds into the yolk of the oocyte.

Expression of aryl hydrocarbon receptor 1 (AHR1), AHR1 nuclear translocator 1 (ARNT1) and CYP1 family monooxygenase mRNAs and their activity in chicken ovarian follicles following in vitro exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

The aim of this in vitro study was to determine the effect of TCDD and luteinizing hormone (LH) on mRNA expression of aryl hydrocarbon receptor 1 (AHR1), AHR1 nuclear translocator 1 (ARNT1), and the CYP1 family monooxygenases (CYP1A4, CYP1A5, CYP1B1), and to assess the basal and TCDD-induced activity of these enzymes in chicken ovarian follicles. White (WF) and yellowish (YF) prehierarchical follicles and fragments of the theca (TL) and granulosa (GL) layers of the 3 largest preovulatory follicles (F3-F1) were exposed to TCDD (10nM), ovine LH (oLH; 10ng/mL) or a combination of TCDD (10nM) and oLH (10ng/mL), and increasing doses of TCDD (0.01-100nM). AHR1 and ARNT1 mRNA transcripts were found in all examined follicles. The effect of TCDD and oLH on AHR1 and ARNT1 mRNA expression depended on the maturational state of the follicle. CYP1A4 was predominantly expressed in the GL of the F3-F1 follicles; in comparison with the WF, a higher level of CYP1A5 mRNA was found both in the GL and TL of F3-F1 follicles. Alternatively, the highest level of CYP1B1 mRNA was noticed in the WF follicles. In different developmental stages of the follicle TCDD and oLH induced a different CYP1 isoform. TCDD increased EROD and MROD activities in all the investigated ovarian follicles. In conclusion, AHR1 and ARNT1 mRNA expression indicate that the chicken ovary is a target tissue for dioxin and dioxin-like compounds. The expression of CYP1-family genes and TCDD-inducible EROD and MROD activities in ovarian follicles suggest the possibility of xenobiotic detoxification in the chicken ovary.