Mouse strain does not influence the overall effects of bisphenol a-induced toxicity in adult antral follicles

Bisphenol A (BPA) is an endocrine-disrupting chemical (EDC) widely used in common consumer products containing polycarbonate plastics and epoxy resins. Previous studies indicate that other EDCs have species-dependent effects. Furthermore, some EDCs are known to have different effects in different strains within the same species. Little information, however, is known about whether the effects of BPA on the ovary differ by strain. Previous studies have shown that BPA inhibits follicle growth, induces atresia, and inhibits steroidogenesis and expression of steroidogenic enzymes in antral follicles from adult FVB mice. Thus, this study was designed to expand previous work by testing the hypothesis that mouse strain may differentially affect the susceptibility of adult antral follicles to BPA-induced toxicity. To test this hypothesis, antral follicles were mechanically isolated from adult FVB, CD-1, and C57BL/6 mice, individually cultured for 6-120 h and treated with either vehicle control (dimethylsulfoxide) or various concentrations of BPA (1.0 μg/ml, 10 μg/ ml, or 100 μg/ml). After culture, media were subjected to measurements of hormone production via ELISA, and follicles were subjected to real-time PCR for analysis of genes known to regulate steroidogenesis, the cell cycle, and atresia. Overall, BPA inhibited follicle growth and steroidogenesis in all tested strains, but CD-1 follicles were slightly more sensitive to BPA at early time points than FVB and C57BL/6 follicles. These data suggest that CD-1, FVB, and C57BL/6 mice can all be used to investigate the effects of BPA on ovarian follicles.