Fenvalerate decreases semen quality in puberty rat through germ cell apoptosis

Fenvalerate, a widely used synthetic pyrethroid insecticide, may adversely affect semen quality in males, but the possible mechanism remains unclear. In our study, forty male SD rats were randomly divided into one control group and three treatment groups administered with fenvalerate (0.02, 1 and 50 mg kg^-1  day^-1 ) by gavage from post-natal day 28 (PND 28) to PND 88. Semen quality parameters were measured by computer-assisted sperm analysis, histological changes in testes were observed by hematoxylin-eosin (HE) staining, germ cell apoptosis was measured by TdT-mediated dUTP Nick-End Labeling (TUNEL) and caspases protein levels were measured by western blotting. Results showed that the increased body weight, the relative testis weight, the sperm concentration and the sperm motility were all significantly reduced in the 50 mg kg^-1  day^-1 fenvalerate group. Increased inner diameter of seminiferous tubules and disturbed array of spermatogenic cells in testicular were observed in fenvalerate exposure groups. Meanwhile, TUNEL-positive germ cells significantly increased in 1 and 50 mg kg^-1  day^-1 fenvalerate exposure groups, and the expression of caspase-8 and caspase-3 in rat testes were also significantly up-regulated. Taken together, our results indicate that fenvalerate has an adverse effect on semen quality, which may be related to germ cell apoptosis.