Cigarette smoking and apoptosis.

Background: Epithelial cell hyperplasia and significant increase in thickness of the overlying orthokeratin layer are characteristic findings noted in the oral cavity of subjects who smoke. Increased proliferation of epithelial cells or defective apoptosis may play a role in the development of epithelial hyperplasia. Thus we analyzed soluble Fas and nuclear matrix protein (NMP) levels in the saliva of smokers (N = 13) and non-smokers (N = 14) to assess apoptosis.

Methods: Ten ml of unstimulated saliva samples was obtained from 14 non-smoker and 13 smoker subjects with the spitting method. These samples were analyzed by using an immunoassay kit to detect soluble human APO-1/Fas and cell death detection enzyme-linked immunosorbent assay (ELISA) kit based on nuclear matrix protein 41/7 qualification.

Results: The mean soluble Fas levels were 153.8 +/- 290 pg/ml and 315.4 +/- 490 pg/ml and NMP levels were 21.81 +/- 10.70 U/ml and 30.31 +/- 19.86 U/ml, respectively, in smokers and nonsmokers. The difference between NMP levels of smoker and non-smoker groups was statistically significant (P = 0.05).

Conclusion: The results of the present study suggest that smoking may induce anti-apoptotic mechanism in the oral cavity.