Detection of benzo(a)pyrene diol epoxide-DNA adducts in sperm of men exposed to cigarette smoke

Objective: To determine whether the adducts formed when benzo(a)pyrene, a d iol epoxide derivative, binds covalently to DNA (BPDE-DNA adducts) are dete ctable in the sperm of men who smoke cigarettes. Design: Prospective study. Setting: The Toronto Hospital IVF-ET program. Patient(s): Twenty-three patients with normal seminal parameters: 11 smoker s (20.6 +/- 0.7 cigarettes per day) and 12 nonsmokers. Intervention(s): Semen samples obtained by masturbation. Main Outcome Measure(s): Seminal plasma samples were assessed for cotinine by RIA. Sperm were treated with dithiothreitol to release disulfide bonds a nd allow for DNA binding, then exposed to an anti-BPDE monoclonal antibody, a biotinylated antibody, and streptavidin-conjugated peroxidase. Staining intensity scores, determined in 100 cells per individual, were correlated w ith seminal plasma cotinine levels, a marker of smoking. Result(s): Cotinine levels correlated highly with the number of cigarettes smoked per day. Mean cotinine levels and mean staining intensity scores wer e higher in smokers than in nonsmokers. Staining intensity correlated highl y with cotinine levels. Conclusion(s): We demonstrated, for the first time, that BPDE-DNA adducts i n sperm cells are increased by smoking; we also detected comparatively high levels in nonsmokers, which indicates that environmental exposure also is substantial. The formation of adducts in spermatozoa is a potential source of transmissible prezygotic DNA damage. (C) 1999 by American Society for Re productive Medicine.