Influence of different iodinated contrast media on the induction of DNA double-strand breaks after in vitro X-ray irradiation.

The objective of this work was to examine differences in DNA double-strand break induction in peripheral blood lymphocytes after in vitro X-ray irradiation between iodinated contrast agents. Four different iodinated X-ray contrast agents - three of them with two different iodine concentrations - and mannitol (negative control; concentration of 150mg mannitol per ml blood) were pipetted into blood samples so that there was a concentration of 0, 7.5 or 15mg of iodine per ml blood in the samples. Negative controls without contrast medium (0mg of iodine per ml blood) were also processed for every irradiation dose. The tubes were exposed to 0, 20 or 500mGy in vitro X-ray irradiation. After that, the lymphocytes were separated by using density-gradient centrifugation. Fluorescence microscopy was applied to determine the average number of H2AX-foci per lymphocyte in the presence or absence of different contrast media or mannitol. Differences in the number of H2AX-foci were statistically analysed by one-way ANOVA and post-hoc Tukey's honestly significant difference test. Iodinated contrast agents led to a statistically significant increase in DNA double-strand breaks after in vitro irradiation. This effect increased statistically significant with rising radiation dose and appeared independent of the contrast agent used (iopromid, iodixanol, iomeprol, iopamidol). A statistically significant difference in DNA damage between the different tested contrast agents was not found. Therefore, the increase in DNA double-strand breaks depends solely on the amount of iodine applied. For evaluation of clinical consequences, our findings could be tested in further animal studies. Copyright (c) 2014 John Wiley & Sons, Ltd.