Chlordecone-induced follicular toxicity in mouse ovaries

The effect of the pesticide, chlordecone, on murine follicular development was examined. Female CD-1 mice were exposed to chlordecone for 5 consecutive days for each of 4 consecutive weeks (0.25 mg/day). Controls received sesame oil vehicle or estradiol-17 beta (E-17 beta; 0.1 mg/day) since chlordecone has been ascribed estrogenic activity. Animals were sacrificed 24 h following the final exposure. Ovaries were removed, serially sectioned, and stained. Follicles were classified as small, medium, or large and were tabulated. Twice as many medium-sized follicles were found in the E-17 beta-treated mice as in both the chlordecone-exposed and sesame oil control groups. Both pesticide- and E-17 beta-exposed mice displayed a much higher percent of atresia in the large follicles; however, there were more actual healthy, large follicles in the E-17 beta group. Thus, both chlordecone and E-17 beta induced increased atresia among large follicles, which could be due to the estrogenicity of these agents. However, a decreased pool of healthy large- and medium-sized follicles occurred in chlordecone-treated mice, a condition not seen in E-17 beta-treated mice. Thus, the pool of potentially ovulatory follicles is reduced in the pesticide-treated animals.