Effects of fumonisin B1 alone and combined with deoxynivalenol or zearalenone on porcine granulosa cell proliferation and steroid production

Fumonisin B1 (FB1) is a Fusarium mycotoxin frequently occurring in corn in combination with deoxynivalenol (DON) and zearalenone. The aim of this study was to determine if FB1, alone and combined with DON or α-zearalenol (ZEA), zearalenone major active metabolite, can affect granulosa cell proliferation, steroid production, and gene expression in swine. Porcine granulosa cells were cultured for 2 days in serum-containing medium followed by 1 or 2 days in serum-free medium with or without added treatments. Fumonisin B1 had inhibitory effects on granulosa cell proliferation. Deoxynivalenol strongly inhibited cell growth, and no significant difference was detected in combination with FB1. α-Zearalenol showed a stimulatory effect on granulosa cell numbers even in combination with FB1. Regarding steroid production, FB1 increased progesterone production, and FB1 had no effect on estradiol production. Deoxynivalenol strongly inhibited progesterone and estradiol production, and FB1 had no significant effect on this response. α-Zearalenol increased progesterone production, and its combination with FB1 produced additive effects. α-Zearalenol had no effect on estradiol production, whereas it decreased estradiol production when co-treated with FB1. Fumonisin B1 was found to decrease CYP11A1 messenger RNA abundance, and the stimulatory effect of FB1 on progesterone production was found to be not dependent on 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity suggesting that FB1 increases progesterone production through a different mechanism. The results show that these Fusarium mycotoxins can influence porcine granulosa cell proliferation and steroid production, thereby demonstrating their potential reproductive effects on swine.