Sperm chromatin damage associated with male smoking

Cigarette smoke is a rich source of mutagens and carcinogens; thus, we have investigated the effects of male smoking on the DNA of human sperm. This w as performed using the sperm chromatin structure assay (SCSA), which measur es the sensitivity of sperm DNA to acid induced denaturation, and the termi nal deoxynucleotidyl transferase assay (TdTA), which measures DNA strand br eaks by addition of the biotinylated nucleotide dUTP to 3'-OH ends of DNA, sites of DNA breakage, using the enzyme terminal deoxynucleotidyl transfera se. Sperm from subjects who smoked were significantly more sensitive to aci d induced denaturation than non-smokers (P < 0.02) and possessed higher lev els of DNA strand breaks (P < 0.05). We hypothesise that smoking damages th e chromatin structure and produces endogenous DNA strand breaks in human sp erm. These changes may result in sperm DNA mutations, that predispose offsp ring to greater risk of malformations, cancer and genetic diseases. (C) 199 9 Elsevier Science B.V. All rights reserved.