Role of Redox-Induced Protein Modifications in Spermatozoa in Health and Disease

Male infertility contributes to approximately half of all infertility cases, with most cases associated with oxidative stress. Spermatozoa depend on finely tuned redox signaling for critical processes such as capacitation, motility, and fertilization competence; however, their unique structural and metabolic features render them particularly vulnerable to oxidative damage. Reversible oxidative modifications regulate enzymatic activity, signaling cascades, and structural stability, supporting normal sperm function, whereas irreversible oxidative damage impairs motility, acrosome reaction, and DNA integrity, contributing to male infertility. The intricate balance between physiological redox signaling and pathological oxidative stress demonstrates the potential of redox modifications as biomarkers for infertility diagnosis and as targets for antioxidant-based therapeutic interventions. This review explores the role of redox-induced protein modifications in sperm function, focusing on thiol oxidation, S-nitrosylation, sulfhydration, glutathionylation, CoAlation, and protein carbonylation. By uncovering the mechanisms of these redox modifications, we provide a framework for their modulation in the development of targeted redox interventions to improve male fertility.