Figure 3. Protective effects of superoxide dismutase (SOD) against NADPH-induced oxidative stress. Uterine sperm ejaculated by males with all major accessory sex glands removed (•; TX without SOD addition in vitro) are more vulnerable to single-strand DNA (ssDNA) damage when incubated with NADPH (⁺⁺⁺P < .001) compared with those from the sham-operated control (). Addition of SOD in the flushing and incubation media significantly decreased the incidence of NADPH-induced ssDNA damage in uterine sperm ejaculated by males with all major accessory sex glands removed (; TX with SOD addition in vitro) compared with those without SOD (•; TX without SOD addition in vitro) in a dose-dependent manner (^***P < .001).