Comet assay and cytokinesis-blocked micronucleus test for monitoring the genotoxic effects of X-ray radiation in humans

Objective To assess the genotoxic effects of X-ray radiation on human popul ations. Methods The single cell gel electrophoresis (SCGE) and cytokinesis-blocked micronucleus (CBMN) test were applied as biological dosimeters to detect DN A damage and abnormalities in human peripheral lymphocytes of subpopulation exposed to X-ray radiation. The subjects were divided into four groups: 12 radiation-patients; 13 intervention-radiation-therapy doctors; 32 radiatio n-diagnostians; 28 controls. Results The average comet lengths of the four groups were 128.17 +/- 4.49 m u m, 88.09 +/- 5.39 mu m, 72.68 +/- 2.57 mu m and 32.87 +/- 0.57 mu m, resp ectively. The difference in average comet length between any two groups was highly significant (P < 0.01). The average micronucleated cell (MNC) rates (parts per thousand) of the four groups were 12.33 +/- 0.85, 9.75 +/- 1.02 , 8.48 +/- 0.66 and 3.18 +/- 0.36, respectively. The difference of MNC rate s of Group 1 vs 3, 1 vs 4, 2 vs 4 and 3 vs 4 was highly significant (P < 0. 01), and the difference of Group 1 vs 2 was significant (P < 0.05), but the re was no difference of MNC rate in Group 2 vs 3 (P > 0.05). Conclusions This study showed that both the comet assay and the CBMN test c ould be used to monitor populations exposed to X-ray radiation, but the com et assay seems to be more sensitive than the CBMN test.