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.