Figure 4

Consequences of PRDXs inactivation in physiological and pathological situations. A) The inactivation of PRDXs due to an increase of H₂O₂ occurs in order to allow the signaling for physiological processes. After the signal is triggered, the GSH and NADPH availability and the presence of an active TRX/TRD system allow the re-activation of PRDX to decrease the intracellular level of H₂O₂. B) Under pathological situations, the already high H₂O₂ levels increase even more as the GSH and NAPDH are depleted. Therefore, PRDXs remain inactive and in consequence, the spermatozoon is not protected against the H₂O₂-dependent damage on lipids, proteins and DNA.