The Effects of the Iodinated X-Ray Contrast Media Iodixanol, Iohexol, Iopromide, and Ioversol on the Rat Kidney Epithelial Cell Line NRK 52-E

Nephrotoxicity, associated with the administration of iodinated X-ray contrast media (ICM), continues to be a major side effect in a significant number of vulnerable patients undergoing diagnostic X-ray imaging procedures. The molecular mechanisms underlying these adverse effects on the kidneys are unclear despite several decades of investigation. Side effects are more common after exposure to high-osmolar compared with low-osmolar ICM, suggesting that osmolality may be an important physical-chemical property related to nephrotoxicity. This investigation in cultured NRK 52-E cells, a cell line of renal origin, compares the in vitro toxicity of the iso-osmolal ICM iodixanol with the low-osmolal ICM iohexol, iopromide, and ioversol. The cellular toxicity was evaluated with the trypan blue exclusion assay, the MTT assay, and incidences of cell death. A qualitative assessment of vacuolation of the cultured NRK 52-E cells was taken as a measure of intracellular uptake of ICM. A difference in cell death incidence was observed between the iso-osmolal iodixanol and the low-osmolal iohexol, iopromide, and ioversol contrast media, with the iso-osmolal iodixanol having the least effect in each of the in vitro systems tested. The osmolality of the contrast media appeared to be the major cause for the observed in vitro toxicity.