Chlamydia trachomatis (CT) is the most dominant sexually transmitted infection of the male genital tract which impairs semen quality and male fertility. Regarding to high DNA fragmentation of sperm in CT infection, it has been proposed that using the antioxidant agents such as vitamin E may ameliorate semen quality of CT infected patients. The aim of this study is to investigate the effects of vitamin E administration on sperm quality improvement in CT infected mice. Twenty four adult mice were distributed in four groups: control, CT infected, CT infected + vitamin E (100 mg/kgbody weight/day), and vitamin E (100 mg/kgbody weight/day) groups. Five days after infection induction, animals were treated with vitamin E for 3 weeks. Then animals were killed and the testicles were removed for sperm analysis, gene expression and western blot experiments. Furthermore, serum levels of sexual hormones were evaluated. CT infection caused a significant reduction in testes weight, testosterone level, and sperm parameters including number, motility, and vitality. Moreover, follicle-stimulating hormone (FSH) level and expression of p53 were significantly higher in CT infected mice in compared with the control group (p < 0.05). Our results showed that sperm parameters, p53 expression, and sexual hormones levels in CT infected + vitamin E group had no significant difference compared with the control group. Vitamin E can be an effective therapeutic agent to improve sperm parameters in CT infected patients possibly via its antioxidant properties
