A comparison of the 8-hydroxydeoxyguanosine and micronucleus techniques for the assessment of X-ray and UV induced genotoxicity.

A comparison was made of the relative sensitivities of the cytokinesis-block micronucleus and the 8-hydroxydeoxyguanosine assays for the assessment of X-ray and UV-induced genotoxicity in mouse splenocytes in vitro. A detectable (p < 0.05) increase in micronuclei occurred at about 1/5 the X-ray exposure required to induce a significant increase in the level of 8-hydroxydeoxyguanosine. With UV radiation a significant (p < 0.05) rise in micronuclei was achieved at about 1/10th the dose needed to produce a detectable increase in 8-hydroxydeoxyguanosine levels. The data confirm the value of the cytokinesis-block micronucleus technique for the detection of genotoxicity at low-level X-irradiation, and indicate that it is more sensitive for that purpose than the 8-hydroxydeoxyguanosine assay. The data also demonstrate, for the first time, the production of 8-hydroxydeoxyguanosine by UVA/B-irradiation of intact cells, but point again to a more sensitive assessment of UV-related genotoxicity by the cytokinesis-block micronucleus method.