Cyclophosphamide is a commonly used anticancer and immunosuppressive drug drug, but it increases reactive oxygen species (ROS) and oxidative stress. Therefore, this study investigated the protective effect of selenium as a potent antioxidant on biochemical factors in adult mice treated with cyclophosphamide. Thirty-two adult male NMRI mice, with an average weight of 36 ± 2 g, were randomly divided into four groups: control, cyclophosphamide (100 mg/kg/bw), selenium (1 mg/kg/bw), and cyclophosphamide + selenium. After a 35-day treatment period, blood samples were collected from the hearts of the mice. Following serum preparation, serum levels of malondialdehyde (MDA) and total antioxidant capacity (TAC) were evaluated. The obtained data were analyzed using SPSS software with one-way ANOVA and Tukey’s test. Differences between means were considered significant at p<0.05. In the cyclophosphamide group, a significant decrease in serum TAC levels and a significant increase in serum MDA levels were observed compared to the control group (p<0.001). However, in the cyclophosphamide + selenium group, serum TAC levels showed a significant increase compared to the cyclophosphamide group (p<0.05). Furthermore, serum MDA levels in the cyclophosphamide + selenium group significantly decreased compared to the cyclophosphamide group (p<0.001). Our results demonstrated that selenium mitigates cyclophosphamide-induced oxidative stress in NMRI male mice. These findings suggest that selenium may serve as a potential antioxidant agent to mitigate cyclophosphamide-induced oxidative damage in reproductive tissue.
