Icariin protects mouse Leydig cell testosterone synthesis from the adverse effects of di(2-ethylhexyl) phthalate

Infertility caused by environmental pollution is becoming a global problem, but an effective prevention or treatment is lacking. Icariin (ICA) is a flavonoid used in traditional Chinese medicine. The present study investigated the possible roles of ICA in preventing testicular dysfunction caused by di(2-ethylhexyl) phthalate (DEHP), one of the most studied environmental endocrine disruptors. Cultured mouse Leydig cells were pre-treated with ICA and exposed to DEHP to determine ICA effects upon cell proliferation, reactive oxygen species (ROS) levels, mitochondrial membrane potential (Delta psi m), testosterone levels and the expression of transcription factor SF-1 and steroidogenic enzymes (CYP11, 3 beta-HSD and 17 beta-HSD), which play critical roles in androgen production. Our results showed that ICA reversed the adverse effect of DEHP on Leydig cell proliferation, and decreased ROS levels and elevated Delta psi m levels. Also, ICA promoted testosterone production and up-regulated the expression of SF-1 and steroidogenic enzymes. We investigated ICA actions in vivo, using male mice administrated DEHP followed by ICA. Exposure to DEHP decreased epididymal sperm counts and disrupted seminiferous tubules, and both of these effects were reversed by ICA treatment. These results showed that the mechanisms of ICA in protecting mouse testes against DEHP-induced damage involves the prevention of ROS accumulation and promotion of testosterone secretion.