Individual and combined effects of deoxynivalenol and zearalenone on bovine granulosa cell proliferation

Deoxynivalenol (DON) and Zearalenone (ZEA) are fusariotoxins frequently found together in commodities used as animal feed. The estrogenic effects of ZEA in all species are well established whereas the effects of DON on the reproductive system are unclear. The purpose of this study is to evaluate the in vitro effects of DON and α-Zearalenol (α-ZEA) on cell proliferation by using bovine granulosa cells (GC). Ovaries from non-pregnant beef cows were collected from a nearby slaughterhouse and large granulosa cells (LGGC) were obtained by aseptically aspirating ovarian follicles (8-22 mm) with an 18-gauge needle. Cells were cultured for 2 days in 5% fetal bovine serum-containing medium followed by 2 days in serum-free medium containing control or mycotoxin treatments. At the end of the experiment, cell numbers were determined using a Coulter counter. The effects of DON and α-ZEA were tested using various dosages (0.1, 0.33, 3.3 µM and 0.09, 0.31, 3.1 µM respectively) and a concomitant treatment with DON at 0.1 µM and α-ZEA at 0.09 µM respectively was also carried out. DON at 3.3 µM decreased cell proliferation whereas the other two treatments with DON had no significant effects. After exposure to α-ZEA, LGGC proliferation was increased by the lowest concentration tested (0.09 µM) while the highest one (3.1 µM) had no effect compared to the control. The combination of these mycotoxins strongly affected LGCC cell growth, increasing cell numbers. The results demonstrate that DON affects cell proliferation mainly at high dosage by decreasing LGGC numbers while α-ZEA can impact cell numbers more at the lowest dosage causing cell proliferation growth. Finally a synergic effect was observed when the mycotoxins are combined. Further studies are in progress to better understand the mechanism of the effects of DON and ZEA on GC.