Individual and combined effects of deoxynivalenol and zearalenone on steroidogenesis in bovine granulosa cells

Zearalenone (ZEA), a phyto-estrogenic molecule, and Deoxynivalenol (DON) are mycotoxins produced by Fusarium spp. and found to co-exist in commodities. Reproductive effects caused by ZEA in ruminants have been reported, while direct effects on fertility related to DON are unknown. The aim of this study is to evaluate steroidogenesis effects of DON and α-Zearalenol (α-ZEA), the hydroxilated metabolite, on bovine granulosa cells (GC). Briefly, small bovine granulosa cells (SMGC) from ovarian follicles (1–5 mm) were cultured at 2.5 x 105 cells/well for 2 days in 5% fetal bovine serum-containing medium followed by 2 days in serum-free medium containing control (no additions) or mycotoxin treatments. Concentrations of progesterone and estradiol in cell culture medium were determined using radioimmunoassay (RIA). DON and α-ZEA were tested at 0.1, 0.33, 3.3 µM and 0.09, 0.31, 3.1 µM respectively and the effects of a combination of the two mycotoxins, at 0.1 µM (DON) and at 0.09 µM (α-ZEA), were also evaluated. Progesterone production was dramatically reduced only after exposure to DON at the highest concentration (3.3 µM) while estradiol production decreased after exposure to all DON and α-ZEA dosages, showing the biggest change after exposure to DON at 3.3 µM. The concomitant treatment with 0.1 µM DON and 0.09 µM α-ZEA respectively showed a synergic inhibitory effect on estradiol production. In conclusion, DON can affect steroidogenesis in bovine SMGC more than α-ZEA , mainly after it has been introduced at high dosages or in combination.