Formation and repair of DNA lesions in kidneys of male mice after acute exposure to methyl chloride.

The time-course of DNA lesions (DNA-protein cross-links, single-strand breaks) induced by high concentrations of methyl chloride (1000 ppm) was measured in renal tissue of male mice by means of the alkaline elution assay in order to gain an insight into repair processes. DNA-protein cross-links were removed at a fast rate, whereas single-strand breaks appeared to accumulate, even during repair of DNA-protein cross-links. However, 48 h after exposure to methyl chloride, neither of these lesions were detectable in mouse kidney. Both types of DNA damage were ascribed to the action of formaldehyde, an intermediate in methyl chloride metabolism which may react with nucleic acids and protein and interfere with DNA repair.