Morphological alterations of ioversol induced cell apoptosis. RLX (10 ng/mL) was added 1.5 hours before ioversol treatment and was in the presence throughout the experiment. HK-2 cells were subjected to ioversol (100 mg/mL) for 30 minutes, and then ioversol was removed, followed by further incubation for 24 hours. Apoptosis was determined using Hoechst 33258 staining (magnification, ×400). Compared with the control, cells treated with ioversol (100 mg/mL) exhibited shrunken nuclear and chromatin condensation, while less apoptotic morphology changes were observed in RLX treated cells.