Alkaline elution assay as a potentially useful method for assessing DNA damage induced in vivo by diazoalkanes

In order to evaluate directly in vivo the extent of correlation existing between mutagenic-carcinogenic activity of diazoalkanes and their DNA damaging activity, alkaline elution was used to study the induction of single-strand breaks in and repair of DNA from mice treated with N-diazoacetylglycine amide (DGA). A dose-dependent DNA fragmentation was present, 4 hr after ip injection of single doses of DGA, in liver, lung, kidney, spleen, thymus, and bone marrow. The differences among these organs in the amount of DNA damage were small, even if sometimes statistically significant. Elution profiles indicated that a progressive conversion of alkali-labile sites to single-strand breaks took place in the first 50 min of elution. Twenty-four hr after treatment with 1000 mg/kg, DNA damage was only slightly reduced in liver, lung and bone marrow. A detailed statistical analysis of the variability of experimental results is reported in order to give information about the reliability of the method, and to allow the possibility of calculating the number of separate experiments required to reach statistical significance for a given increase of DNA elution rate.