BREAKAGE OF LAMBDA-DNA BY INORGANIC TIN AND ORGANOTIN COMPOUNDS AS ENVIRONMENTAL-POLLUTANTS

In proportion to the environmental pollution problems caused by organo tin compounds, the genotoxicities of tin compounds in the environments have become of interest so as to estimate their safety in recent year s. In this work, isolated lambda-DNA (doubIe-strand DNA) was incubated with inorganic tin(II) and tin(IV) and five organotin compounds [n-bu tyltin trichloride, di(n-butyltin) dichloride, methyltin trichloride, dimethyltin dichloride and trimethyltin chloride] in reaction systems both with and without hydrogen peroxide (H2O2) content. The tin compou nds tested in this study did not induce DNA breakage in the absence of hydrogen peroxide. Divalent inorganic tin (SnCl2) and tetravalent ino rganic tin (SnCl4) caused DNA breakage in the presence of hydrogen per oxide (10 mM), and the DNA damage activity of inorganic tin was much m ore potent in divalent inorganic tin (SnCl2) than in tetravalent inorg anic tin (SnCl4). Divalent inorganic tin (SnCl2,) induced DNA breakage in a concentration-dependent fashion at concentrations greater than O .lmM of SnCl2 in the presence of hydrogen peroxide (10mM). DNA breakag e was not caused by n-butyltin compounds and methyltin compounds eithe r in the presence or in the absence of hydrogen peroxide.