Effects of sodium fluoride and sulfur dioxide on oxidative stress and antioxidant defenses in rat testes

To assess effects of sodium fluoride and sulfur dioxide on oxidative stress and antioxidant defenses in the testes, 96 sexually mature male Wistar rats were divided randomly into four groups of twenty-four rats each. One group of rats was left untreated as controls, and the other three groups were administered, respectively, for eight consecutive weeks, 100 mg NaF/L (45 mg F-/L) in their drinking water, sulfur dioxide in ambient air (15 ppm SO2, 4 hr/day), or were exposed to the same levels of both NaF and SO2 together. In comparison with the control group, testis glutathione peroxidase (GSH-Px) activity significantly increased in the SO2 group and in the NaF+SO2 group in the 2(nd) and 6(th) week of exposure. Superoxide dismutase (SOD) activities also increased markedly in the NaF group at week 2, in the SO2 group at weeks 2 and 6, and in the NaF+SO2 group from week 6 to week 8. Increased malondialdehyde (MDA) levels occurred in the NaF group at week 6, in the SO2 group at weeks 2, 6, and 8, and in the NaF+SO2 group from week 4 to week 8. However, the ratios of SOD activity and MDA content in treated groups were lower than those of the control group, especially in the NaF+SO2 group at week 6. These results suggest that oxidative stress from NaF and SO2 in the testes may be one of the causes of reduced sperm motility in male rats.