Zonisamide (ZNS) is an anticonvulsant which is used to treat the symptoms of epilepsy. Although it is frequently used during reproductive ages, studies that investigated the effects of ZNS on reproductive system are limited. Therefore, we aimed to assess the effects of ZNS on male reproductive system by oral administration to rats in 25, 50, and 100 mg/kg doses for 28 days. After the exposure period, sperm concentration, motility, morphology, and DNA damage, as biomarkers of reproductive toxic effects, were determined, and histopathological examination of testis was performed. In addition, levels of the hormones that play a role in the regulation of reproductive functions, such as follicle-stimulating hormone, luteinizing hormone (LH), and testosterone were measured and the levels of oxidative stress biomarkers that take part in the reproductive pathologies such as catalase, superoxide dismutase, glutathione, and malondialdehyde, were determined. Reproductive toxic effects related to ZNS administration were shown by the significant decrease of sperm concentration and normal sperm morphology in ZNS groups. Additionally, pathological findings were observed in the testicular tissues of ZNS-administered groups dose dependently. In addition, serum LH and testosterone levels were significantly decreased in the ZNS groups. Decreased catalase activities and increased malondialdehyde levels in ZNS groups were evaluated as oxidative stress findings in the testis tissue. It could be expressed that ZNS administration induced dose-dependent reproductive toxic effects in rats, and pathological findings associated with the reproductive system could be the result of that hormonal changes and testicular oxidative stress, which in turn might be considered as possible mechanisms of male reproductive toxicity.
Keywords: Zonisamide; oxidative stress; reproductive hormones; sperm parameters; testicular histology.