In vitro effects of fumonisin B1 alone and combined with deoxynivalenol or β-zearalenol on bovine granulosa cell proliferation and steroid production

Fumonisin B1 (FB1) is a common maize contaminant frequently in co-occurence with deoxynivalenol (DON) and zearalenone (ZEA). Potential reproductive effects of FB1 alone or in combination have been poorly investigated in animal species (Cortinovis et al., 2014) and no information is available in cattle. Thus, the goal of this study was to determine if FB1 alone and combined with DON and/or β-zearalenol (β-ZEA), ZEA hydroxylated metabolite, can affect granulosa cell proliferation and steroid production. Ovaries from non-pregnant beef cows were collected from a local slaughterhouse and follicular fluid was aspirated from small follicles (1-5 mm) to isolate granulosa cells. Granulosa cells were cultured for 2 days in 10% fetal bovine serum followed by 2 days in serum-free medium containing 500 ng/ml of testosterone (as an estradiol precursor), 30 ng/ml of FSH and 30 ng/ml of IGF-I with FB1 (0, 30, 100 ng/ml), DON (0 or 100 ng/ml) and β-ZEA (0 or 30 ng/ml). The results revealed that FB1 alone at all doses had no effect on granulosa cell numbers and steroidogenesis. In the presence of β-ZEA, FB1 at 30 ng/ml showed a stimulatory effect on granulosa cell numbers, whereas no significant interaction existed between FB1 and DON and between FB1, β-ZEA and DON. In regard to progesterone production, FB1 at 100 ng/ml showed a stimulatory effect in cells treated with β-ZEA, whereas no significant interaction was observed between FB1 and DON alone or with β-ZEA. Finally, FB1 (30 ng/ml and 100 ng/ml) was found to enhance the inhibitory effect of β-ZEA on estradiol production. In conclusion, the present study demonstrates that significant toxicological effects of FB1 are observed in co-exposure with β-ZEA in a bovine granulosa cell model. References: Cortinovis C, Caloni F, Schreiber NB, Spicer LJ, 2014. Effects of fumonisin B1 alone and combined with deoxynivalenol or zearalenone on porcine granulosa cell proliferation and steroid production. Theriogenology 81, 1042-1049.