The effects of environmentally relevant amounts of ethinyl estradiol on the gonad histology and oxidative enzymes of Corbicula fluminea

Abstract

Ethinyl estradiol (EE2) is an endocrine disrupting compound that is commonly used as an ingredient in many contraceptive pills. Endocrine disrupting compounds have been known to cause adverse effects on various organ systems in organisms most notably in the form oxidative stress. Enzyme analysis of soft tissues and histological analysis of the gonads were conducted on samples of Corbicula fluminea that were exposed to varying levels of environmentally relevant EE2. Results of the oxidative assays showed that there were no significanct differences among the treatment groups; however, anomalies were seen in the gonad histology of the clams. All female gonads of test clams exhibited disintegration membrane and thinning of connective tissues as well as the appearance of binucleolation of the germinal vesicles of some oocytes while male gonads exhibited a lag in spermatogenic cell development resulting into the lack of mature spermatozoa in higher exposures of EE2; however, these anomalies are only classified as early signs of damage suggesting that EE2 has the capacity to induce greater oxidative stress damage at higher concentrations than those used in this study.