Dose- and time-dependent effects of bisphenol A on bovine spermatozoa in vitro.

The present study was to evaluate the effect of bisphenol A (BPA) at the doses 1, 10, 100 and 200 µg mL(-1) on the bovine spermatozoa motility, viability and production of superoxide radical. The CASA system was used to determine the spermatozoa motility. The initial motility showed the significant differences (P < 0.001) between the groups higher than 100 µg BPA mL(-1) and the control group. Evaluation of the spermatozoa motility after 6 h of cultivation at the doses > 10 µg BPA mL(-1) was found to decrease motility significantly. After 24 h it was observed that the doses < 10 µg BPA mL(-1) statistically increased motility, while the doses > 100 µg BPA mL(-1) significantly decreased motility in comparison to control. The viability of spermatozoa as detected by the MTT assay decreased in all experimental groups, but significant differences were noted only at the highest doses of BPA after 24 h of in vitro cultivation. The intracellular superoxide production was observed by the NBT test after 24 h of BPA exposure. The results indicated that in all experimental groups the amount of superoxide increased as compared to the control group; significant changes were observed at the doses > 100 µg BPA mL(-1). In conclusion, the results from our experiments suggest the negative effects of BPA at the highest doses used on motility and viability of bovine spermatozoa and production of superoxide radical.