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Tobacco smoking is deleterious to reproduction. Benzo[a]pyrene (B[a]P) is a potent carcinogen in cigarette smoke. Its reactive metabolite induces DNA-adducts, which can cause mutations. We investigated whether B[a]P diol epoxide (BPDE) DNA adducts are detectable in preimplantation embryos in relation to parental smoking. A total of 17 couples were classified by their smoking habits: (i) both partners smoke; (ii) wife non-smoker, husband smokes; and (iii) both partners were non-smokers. Their 27 embryos were exposed to an anti-BPDE monoclonal antibody that recognizes BPDE-DNA adducts. Immunostaining was assessed in each embryo and an intensity score was calculated for embryos in each smoking group. The proportion of blastomeres which stained was higher for embryos of smokers than for non-smokers (0.723 versus 0.310). The mean intensity score was also higher for embryos of smokers (1.40+/-0.28) than for non-smokers (0.38+/-0.14; P = 0.015), but was similar for both types of smoking couples. The mean intensity score was positively correlated with the number of cigarettes smoked by fathers (P = 0.02). Increased mean immunostaining in embryos from smokers, relative to non-smokers, indicates a relationship with parental smoking. The similar levels of immunostaining in embryos from both types of smoking couples suggest that transmission of modified DNA is mainly through spermatozoa. We confirmed paternal transmission of modified DNA by detection of DNA adducts in spermatozoa of a smoker father and his embryo.

Benzo[a]-pyrene (B[a]P) is a potent mutagen and carcinogen present in cigarettes. We report here on immunodetection and quantification of B[a]P-DNA adducts in granulosa-lutein cells of patients undergoing in-vitro fertilization (IVF) and embryo transfer, who were exposed to cigarette smoke. Follicular fluids (FF) and granulosa-lutein cells were obtained from the same follicular aspirate from 32 women self-reported as active smokers, passive smokers, or non-smokers. Cells were immunostained with 5D11, an anti-B[a]P diolepoxide monoclonal antibody that recognizes DNA adducts. Cotinine, a reliable marker for recent smoke exposure and dose, was assessed by radioimmunoassay in 32 FF samples. Individual scores of cell immunoreactivity were highly correlated with FF cotinine concentrations. Evaluations of immunostaining intensity in 9770 granulosa-lutein cells from the 32 women revealed higher average scores in active and passive smokers, relative to non-smokers. In passive smokers the average level of cell immunostaining was 63% of that of active smokers. These relationships provide quantitative evidence that B[a]P-DNA adduct levels are related to smoke exposure and dose, both recent and long term. Immunostaining was confined to the nucleus, suggesting adduct formation by covalent binding to DNA. Presence of adducts in granulosa-lutein cells from women exposed to cigarette smoke may increase the risk for DNA damage.