Effects of BPA on zebrafish gonads: Focus on the endocannabinoid system.

Bisphenol A (BPA), a monomer used for polycarbonate manufacture, has been widely reported as an endocrine-disrupting chemical (EDC). Among other alterations, BPA induces reproductive dysfunctionalities. Changes in the endocannabinoid system (ECS) has been recently shown to be associated with reproductive disorders. ECS is a lipid-based signaling system (cannabinoid receptors, endocannabinoids and enzymatic machinery) involved in several physiological functions. The main goal of the present study was to assess the effects of two environmental concentrations of BPA (10 and 20 μg/L) on the ECS in 1-year zebrafish gonads. In the males, BPA increased the gonadosomatic index (GSI) and altered testicular levels of endocannabinoids as well as reduced the testicular area occupied by spermatogonia. In the male liver, exposure to 20 μg/L BPA significantly increased vitellogenin (vtg) transcript levels. In female zebrafish, BPA altered ovarian endocannabinoid levels, elevated hepatic vtg mRNA levels as well as increased the percentage of vitellogenic oocytes in the ovaries. In conclusion, exposure to two environmentally relevant concentrations of BPA altered ECS and consequently, gonadal function in both male and female zebrafish.