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.