Induction of mitotic micronuclei by X-ray contrast media in human peripheral lymphocytes

In vitro and in vivo cytogenetic effects of X-ray contrast media (CM) were determined by scoring micronuclei (MN) in 72-h cultures of human peripheral lymphocytes. Both ionic (sodium meglumine diatrizoate, methylglucamine diatrizoate, and sodium meglumine ioxaglate and nonionic CM (iosimide, iopromide, iohexol and iotrolan) were able to induce MN in lymphocytes. Based upon their calculated percent probabilities for MN induction, these agents could be ranked in their decreasing order of probability, as iosimide greater than sodium meglumine ioxaglate greater than iohexol greater than sodium meglumine diatrizoate greater than iopromide greater than methylglucamine diatrizoate greater than iotrolan. Stepwise logistic regression analysis of the data indicated that the frequency of MN in CM-exposed lymphocyte cultures was significantly higher than the frequency of MN in control cultures (P less than 0.001). In clinical studies where 14 patients were injected with an ionic CM methylglucamine diatrizoate, lymphocyte cultures from 10 patients showed higher frequencies of MN. The differences between pre- and post-CM counts of MN were significant in a Mann-Whitney U test (P less than 0.05). The effect of X-irradiation on MN formation in lymphocytes was separately determined and was found to be insignificant. These results indicate that irrespective of ionic and osmolality differences, X-ray contrast agents are capable of producing chromosomal damage in peripheral lymphocytes. Further studies are required to establish molecular mechanisms in the observed cytogenetic effects of CM in cell cultures.