gms | German Medical Science

Introduction: Tobacco ingredients are risk factors for carcinogenesis in the upper aerodigestiv tract. DNA-damage induced by nicotine was detected in different human tissues, e. g. tonsillar tissue, salivary glands and nasal mucosa. Mini organ cultures of nasal mucosa (MOC) demonstrate an adequate model for analysing repetive or permanent exposure to nicotine. Aim of this study was to demonstrate nicotine induced DNA-damage after longterm nicotine exposure of MOC.

Methods: Nasal mucosa specimens were obtained during surgery of the human nasal passage and were cut into 1 mm³ tissue cubes and cultured for 21 days in 24-well plates as MOC. The exposure of 1 µM and 1 mM nicotine lasted 21 days, thereby medium and nicotine were exchanged every third day. Genotoxic effects were analysed by the comet assay after isolation of single cells on days 7, 14 and 21.

Result: The exposure of 1 µM and 1 mM nicotine shows a significant dose dependent DNA-migration after 7 days in the comet assay. After 14 and 21 days of nicotine exposure a decrease of the induced DNA-damages was noticed as compared to day 7.

Conclusion: MOC are suitable for analysing longterm exposure to xenobiotics. The present results confirm a decrease of the induced DNA-damages during long time exposure shown in prior studies in lymphocytes. Further investigations should focus on enzyme induction as a possible factor of a decrease of toxicity.