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Cigarette smoking and aneuploidy in human sperm
1Department of Medical Genetics, The University of Calgary, Calgary, Alberta, Canada.
Abstract:
Cigarette smoke contains chemicals which are capable of inducing aneuploidy in experimental systems. These chemicals have been shown to reach the male reproductive system, increasing oxidative DNA damage in human sperm and lowering semen quality. We have examined the association between smoking and aneuploid sperm by studying 31 Chinese men with similar demographic characteristics and lifestyle factors except for cigarette smoking. None of the men drank alcohol. These men were divided into three groups: nonsmokers (10 men), light smokers (< 20 cigarettes/day, 11 men), and heavy smokers (> or = 20 cigarettes/day, 10 men). There were no significant differences in semen parameters or in age across groups. Two multi-color fluorescence in situ hybridizations (FISH) were performed: two-color FISH for chromosomes 13 and 21, and three-color FISH for the sex chromosomes using chromosome 1 as an internal autosomal control for diploidy and lack of hybridization. The mean hybridization efficiency was 99.78%. The frequency of disomy 13 was significantly higher in light and heavy smokers than in non-smokers, while no significant differences in the frequency of disomy 21, X or Y were observed across groups. Significant inter-donor heterogeneity in every category of disomic sperm examined was found in both light and heavy smokers, while in nonsmokers only XY disomy showed significant inter-donor differences. Thus, we conclude that cigarette smoking may increase the risk of aneuploidy only for certain chromosomes and that men may have different susceptibilities to aneuploidy in germ cells induced by cigarette smoking. Mol. Reprod. Dev. 59: 417-421, 2001.
Insights
Cigarette smoking significantly increases the risk of aneuploidy (abnormal chromosome number) in sperm, particularly for chromosome 13. Individual susceptibility to smoking-induced germ cell aneuploidy varies among men.
Area of Science:
- Reproductive Biology
- Toxicology
- Genetics
Background:
- Cigarette smoke contains chemicals that can induce aneuploidy.
- These chemicals reach the male reproductive system, increasing DNA damage and lowering semen quality.
Purpose of the Study:
- To examine the association between cigarette smoking and aneuploid sperm in Chinese men.
- To investigate if smoking affects specific chromosome aneuploidies and individual susceptibility.
Main Methods:
- Studied 31 Chinese men divided into non-smokers, light smokers, and heavy smokers.
- Utilized multi-color fluorescence in situ hybridization (FISH) for chromosomes 13, 21, and sex chromosomes.
- Analyzed hybridization efficiency and frequency of disomies (aneuploidy).
Main Results:
- The frequency of disomy 13 was significantly higher in both light and heavy smokers compared to non-smokers.
- No significant differences in disomy 21, X, or Y frequencies were observed across groups.
- Significant inter-donor heterogeneity in disomic sperm was noted, especially in smokers.
Conclusions:
- Cigarette smoking may increase aneuploidy risk for specific chromosomes, like chromosome 13.
- Individual susceptibility to cigarette smoking-induced germ cell aneuploidy varies among men.