[Cytotoxicity caused by tobacco]

Condensed smoke (CS) at as concentration of 0.40 mg/ml as well as urethane at 5.0 mg/ml reduced cell adherence and proliferation at percentages lower than 30 and 15% respectively. Control cells displayed 100% adherence and proliferation. Tobacco extract (TE) at 16 mg/ml inhibited cell proliferation in 65%, at 0.75 mg/ml or lower doses results were similar to control cultures and 0.1 mg/ml cell proliferation increases by 15 to 40% above controls. Urethane at 0.10 mg/ml to 0.30 mg/ml to 0.30 mg/ml favored cell proliferation by 55% above control. CS at 0.05 to 0.10 mg/ml presented similar adherence and proliferation results as control cells. MDCK cells treated with ethylenemethanesulphonate and subsequently expanded under normal conditions were incubated with CS, TE and urethane at different concentrations. Their behavior was similar to control MDCK cells. Cell cultures incubated for 3 days after their exposure to CS (0.05 mg/ml) or urethane (2.5 mg/ml) showed 50% inhibition of proliferation when compared to controls. Data obtained in this study indicate that high doses of PDCT are cytotoxic which is reflected in the inhibition of cell adherence and proliferation while low doses of PDTC stimulate these cellular phenomena.