The epididymal maturation is a key element in the development of the ability of the male gamete to fertilize the oocyte. Among the many components involved in this process, reactive oxygen species (ROS) are essential as beneficial in some respects, however, they are toxic in excess. GPX5 a form of epididymal glutathione peroxidase, could play a role in controlling redox environment sperm. Production in vitro by a recombinant baculovirus GPX5 was performed, but the virus was highly unstable and was therefore not possible to analyze this protein biochemically. Approach initiated in vivo by passive immunization did not show impaired fertility in mice. It was supplemented by the developement of a broader study based on the generation of mice inactivated for the gene GPX5. These have normal fertility, however, developmental changes were observed in the offspring of older males. Disturbances are associated with changes in the expression of many antioxidant enzymes such as catalase and GPXS, but only in the tail of the epididymis. In addition, an increase in oxidative damage to DNA is visualized in the epithelium of cauda epididymal sperm and in this region. Selenium deficiency has been initiated to thwart a éventuellle functional compensation from other epididymal GPx. Initiation of apoptotic pathways is observed in animals deficient KO GPX5 and in the tail of the epididymis. Surprisingly, redox disturbances are also displayed in other organs such as the liver and testis.
