Individual and combined effects of fumonisin B1 and deoxynivalenol or zearalenone on porcine granulosa cell proliferation

Fumonisins are mycotoxins mainly produced by Fusarium verticillioides and Fusarium proliferatum that have been shown to occur worldwide at significant levels in corn and corn by-products. Fumonisin B1 (FB1) is the most abundant and toxic and causes a variety of species-specific toxic effects in domestic animals e.g. equine leukoencephalomalacia and porcine pulmonary oedema. So far, very little information is available on the potential reproductive toxicity of FB1. Therefore, the aim of the present study was to assess if FB1, alone or in combination with deoxynivalenol (DON) or zearalenone (ZEA), can impact reproductive performance in swine via affecting granulosa cell proliferation. Granulosa cells from small porcine follicles (1-5 mm) were cultured for 2 days in 5% foetal bovine serum and 5% porcine serum-containing medium followed by 2 days in serum-free medium containing 30 ng/ml of FSH and 30 ng/ml of IGF-I with or without FB1 (10 M), DON (3.4 M) and ZEA (9.4 M). On day 4 of culture, numbers of granulosa cells were determined using a Coulter counter. Treatment effects and interactions were assessed using the GLM procedure of the Statistical Analysis System. FB1 showed an inhibitory effect (P < 0.05) on granulosa cell proliferation induced by FSH plus IGF-I; cell numbers were decreased by 21%. DON strongly inhibited (by 80%; P < 0.0001) granulosa cell proliferation and no significant difference was detected in combination with FB1. ZEA showed a stimulatory effect (P < 0.01) on granulosa cell growth even when treated in combination with FB1. Results of the present study indicate that FB1 has direct effects on proliferation of porcine granulosa cell and thus may be able to alter in growth of the granulosa layer within ovarian follicles. The interaction between FB1 and DON or ZEA was also evaluated. No additive or synergistic effects were observed after combined exposure to DON and FB1. ZEA showed a stimulatory effect on granulosa cell proliferation even in combination with FB1.