Role of protamine disulphide cross-linking in counteracting oxidative damage to DNA

Abstract

Free radical (oxygen and nitrogen-derived)-induced sperm DNA damage may take place during the process of spermatogenesis, during sperm transit through the epididymis, in the distal seminal ducts of the male genital tract and in vitro during sperm processing. Free radical-induced DNA damage during spermatogenesis may result in damage of the DNA strands and of highly sensitive telomeric DNA sequences. Post-testicular sperm DNA damage in the epididymis is considered one of the main causes of sperm DNA damage. Release of oxygen radical-producing immature spermatozoa into seminiferous tubules may result in damage of mature spermatozoa during co-migration spermatozoa through the epididymis. Posttesticular free radical-induced sperm DNA damage may also take place in the proximal portion of the epididymis through free radicals such as the superoxide anion that leak from redox recycling mechanisms involved in disulphide bond crosslinking of protamines and fl agellar proteins; in the cauda epididymis through free radicals produced by the epithelial cells; and during sperm processing.