Effects of contrast media on renal epithelial cells in culture

Proximal and distal tubular cells in culture have been exposed to various roentgen contrast media (CM) at concentrations of 0 to 100 mg I/ml for 22 hours to study cellular mechanisms that may be involved in CM-induced nephropathy. The effects on cell morphology were assessed by electron microscopy and cell viability was evaluated. Levels of brush border and lysosomal marker enzymes in the culture medium were assayed biochemically. Morphological examination showed that CM induced a concentration-dependent formation of large cytoplasmic vacuoles in both cell lines. Cellular damage was observed more frequently after exposure to low-osmolal rather than the iso-osmolal CM iodixanol; the low-osmolal CM causing more cell death and inhibiting cellular growth to a greater degree than did iodixanol. In cultures of both cell lines the CM produced a concentration-dependent increase in brush border marker enzyme activity. While an increase in lysosomal enzyme activity was seen at low concentrations, a decrease in activity occurred at high concentrations. Earlier investigations have demonstrated that the nonionic CM have less pronounced effects on the cell lines studied than ionic CM. The results presented here indicate that the effects of the iso-osmolal nonionic CM (iodixanol) on both the investigated cell lines are less marked than those of the low-osmolal nonionic CM investigated.