AbstractObjective:Paclitaxel (PAC) is a chemotherapy drug and has an active role in the treatment of lung, breast, and ovarian cancers; however, its use causes increased levels of free radicals, leading to severe and irreversible organ damage. Thymus vulgaris is a species of flowering plant that contains various antioxidant chemical compounds. This study aimed to investigate the effect of T. vulgaris on PAC-induced oxidative damage in mice testis and sperm parameters.Methods:In this study, 40 BALB/c mice were pided into five groups: normal control (NC); positive control (20 mg/kg of PAC); and three treatment groups (4.5, 9, and 18 mg/kg doses of T. vulgaris extract + 20 mg/kg PAC). Treatments were administered intraperitoneally daily for 50 days. Finally, the levels of serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone were measured using immunoassay method. Testicular stereological features and sperm parameters were also calculated. Antioxidant parameters were measured using nitrite oxide (NO) and perioxidation levels and ferric-reducing ability of plasma assay. The expressions of p53, caspase-3, Bax, and Bcl-2 were measured through real-time quantitative polymerase chain reaction.Results:T. vulgaris + PAC treatments at all doses significantly increased all parameters in NC and three treatment groups compared with the positive control group (20 mg/kg of PAC) (P < 0.05), except the LH, FSH, and NO levels, which were decreased. Further, significantly downregulated levels of p53, caspase-3, and Bax genes and upregulated levels of Bcl-2 gene expression were noted in NC and three treatment groups in comparison with the positive control group (P < 0.05).Conclusions:T. vulgaris administration attenuates the toxic effects of PAC on male reproductive parameters.
