The influence of deoxynivalenol and zearalenone on steroid hormone production by porcine ovarian granulosa cells in vitro

Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEA) are frequently occurring in feed of pigs together. The aim of this study was to evaluate the possible in vitro effects of DON and ZEA, alone or their combination on steroid secretion of porcine ovarian granulosa cells (GCs). A species-specific model with porcine ovarian GCs was used to study the potential endocrine disrupting effects of DON and ZEA alone and in co-exposure. Progesterone (P4) and estradiol (E2) were determined by radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). The results of this study demonstrate that DON alone at the higher concentrations may act to stimulate P4 (at 1,000, 2,000, 3,000 and 5,000 ng mL^?1 but not 10 and 100 ng mL^?1) and E2 (at 2,000, 3,000 and 5,000 ng mL^?1 but not 10, 100 and 1000 ng mL^?1) secretion. The effects of ZEA on P4 and E2 secretion were not confirmed. DON in combination with the other fusariotoxin ZEA may impair steroidogenesis. Results aslo demonstrate different toxicological effects of fusariotoxins on follicle stimulating hormone-induced secretion of P4 and E2. All these results taken together suggest that fusariotoxin and their interactions can impact ovarian steroidogenesis, thereby demonstrating their potential reproductive effects in pigs.     

Dietary bioflavonoid quercetin modulates porcine ovarian granulosa cell functions in vitro

Quercetin is a dietary bioflavonoid used widely as a food supplement and is generally recognized as safe. The aim of this in vitro study was to examine the steroid hormone (progesterone and 17- β estradiol) release, proliferation (PCNA and cyclin B1) and apoptosis (caspase 3 and p53) of porcine ovarian granulosa cells after the addition of quercetin at concentrations 0.01, 0.1, 1, 10 and 100?μmol?L^?1. Progesterone release was stimulated at the concentration 10?μmol?L^?1. Quercetin neither had any impact on 17-β estradiol secretion nor on the presence of PCNA. However, a significant enhancement of the occurrence of cyclin B1 was noted except for the lowest concentration 0.01?μmol?L^?1. Quercetin did not have any influence on the number of granulosa cells containing caspase 3, but at the concentration 10?μmol?L^?1 it inhibited p53 occurrence. Results confirm the safety of quercetin in porcine ovarian granulosa cell model and further suggest its possible concentration-dependent influence on ovarian functions through pathway that may involve progesterone, cyclin B1 and p53.     

Cobalt-induced hormonal and intracellular alterations in rat ovarian fragments in vitro

The objective of this in vitro study was to examine dose-dependent changes in the secretion activity (progesterone, 17β-estradiol and insulin-like growth factor-I) of rat ovarian fragments after experimental cobalt (Co) administration including the apoptotic potential of Co on rat ovarian fragments by evaluating the expression of apoptotic markers Bax and caspase-3. Ovarian fragments were incubated with cobalt sulphate (CoSO₄.7H₂O) at the doses 90, 170, 330 and 500 μg.mL^?1 for 24 h and compared with control group without Co addition. Release of progesterone (P₄) 17β-estradiol and insulin-like growth factor-I (IGF-I) by ovarian fragments was assessed by RIA, expression of Bax and caspase-3 by SDS-PAGE and Western blotting. Observations show that P₄ release by ovarian fragments was significantly (P < 0.05) inhibited after cobalt sulphate addition at higher doses 170–500 μg.mL^?1 used in the study in comparison to control. However, cobalt sulphate addition did not cause any significant change in the release of 17β-estradiol by ovarian fragments at all the doses used in the study (90–500 μg.mL^?1) in comparison to control. On the contrary, IGF-I release by ovarian fragments was significantly (P < 0.05) stimulated after cobalt sulphate addition at the lowest dose 90 μg.mL^?1 in comparison to control, while other doses did not cause any significant change. Also, addition of cobalt sulphate decreased the expression of both the apoptotic peptides Bax and caspase-3 at the higher doses 170, 330 and 500 μg.mL^?1, but not at the lowest dose 90 μg.mL^?1 used in the study. Obtained results suggest Co induced (1) inhibition in secretion of steroid hormone progesterone, (2) dose-dependent increase in the release of growth factor IGF-I, and (3) decrease in the expression of markers of apoptosis (Bax and caspase-3) of rat ovarian fragments.