[Research on the effect of iodinate contrast agent on the DNA radiation damage at CT]

Objective: To evaluate the effect of iodinate contrast agent (ICA) on the formation of DNA double-stand breaks (DSBs) in human peripheral blood lymphocytes during computed tomography (CT) examinations. Methods: Peripheral venous blood (16 ml/person) of 36 volunteers were collected during the period of February to May 2016. Each blood sample was divided into 8 tubes and 4 groups on average, which were marked as groups of A, B, C, D randomly. 25 μl ICA was respectively added into one tube of each group and the groups of B, C, D accepted the same CT scan for once, twice and three times. The lymphocytes in these blood samples were separated by using density-gradient centrifugation, fixed and immunostained with γH2AX antibody. The average number of phosphorylated histone H2AX (γH2AX) foci per lymphocyte was counted under a fluorescence microscopy. Results: The numbers of γH2AX foci were increased approximately 82.9% ((0.064±0.025) vs (0.035±0.010) foci/cell) if ICA was simply added into the blood. With the increase of CT radiation, the foci numbers of the groups of B, C, D would increase and the samples containing ICA could have a more amount of foci numbers than those without ICA (B: (1.217±0.158) vs (0.774±0.258); C: (2.128±0.185) vs (1.569±0.201); D: (3.812±0.490) vs (2.938±0.480) foci/cell). The more radiation it had, the more significant the difference of foci numbers would be ((0.489±0.323), (0.549±0.278), (0.692±0.462) foci/cell). Conclusion: The ICA itself can lead to an increase of the DSBs level and the application of ICA can amplify the DNA damage as assessed with γH2AX foci formation during diagnostic X-ray procedures.