Impact of Oxidative Stress on Reproductive Toxicity Induced by Alpha-Terpineol in Male Sprague-Dawley Rats

α-Terpineol, a monoterpene found in essential oils and fragrances, has been reported to exhibit reproductive toxicity. The present study investigates the impact of oxidative stress on reproductive toxicity induced by α-Terpineol in male rats. α-Terpineol was administered to rats at various doses (0, 75, 150, and 300 mg/kg/day) via oral gavage for 28 days. Endpoints assessed included sperm parameters, testicular histopathology, morphology, and the expression of Nrf2 a key regulator of cellular antioxidant defense, using immunohistochemistry, serum hormone analysis, and markers of oxidative stress in the testes malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), ferric reducing antioxidant power (FRAP) assay, and protein carbonyl content (PC) assay. Results demonstrated that α-Terpineol significantly induced oxidative stress as evidenced by increased MDA levels and decreased SOD, GSH, CAT, activities, and FRAP level. Furthermore, α-Terpineol exposure resulted in a dose-dependent reduction in sperm motility and concentration, increased abnormal sperm morphology, decreased serum testosterone, FSH and LH levels, and histopathological alterations in the testes indicating disruption of the hypothalamic-pituitary-gonadal axis. These findings suggest that oxidative stress plays a crucial role in α-Terpineol-induced reproductive toxicity in male rats, potentially through disruption of antioxidant defense mechanisms and subsequent damage to testicular tissues and sperm.