The Effect Of Autophagy On Iodinated Contrast Media Induced Human Proximal Renal Tubular Epithelial Cytotoxicity

ObjectiveTo observe autophay of HK-2cell induced by iodinated contrast media, and to investigate the role of autophagy in iodinated contrast media induced HK-2cell injury and apoptosis.Methods1. HK-2cells were incubated with or without iodinated contrast media of Iohexol (200mg I/ml) for3h and6h, respectively. The protein expressions of LC3Ⅱ and Atg7were detected by Western Blot. LC3II-FITC fluorescence confocal microscopy and transmission electron microscopy were used to observe autophagosome formation in cytoplasm6h after exposure.2. HK-2cells were incubated with or without Iohexol (200mg I/ml), for6h.3-MA (10mmol/l) was used to inhibit the initiation of autophagosome. Western Blot analysis was also used to detect the protein expressions of LC3Ⅱ and Atg7. LDH released into the supernatant were measured to evaluate the degree of cell injury. Apoptosis was determined by flow cytometry.Results1. Electron micrographs showing autophagosomes and autophagic vesicles in Iohexol-treated HK-2cells. Fluorescence staining of LC3Ⅱ FITC showed Iohexol induced an increase in the numbers of autophagosomes at6h.compared with control group, the expression of LC3Ⅱ and Atg7were significantly increased in HK-2incubated with iohexol in a time-dependent manner (P<0.05).2. Expression of LC3Ⅱ and Atg7were depressed by3-MA compared with controls (P<0.05). At the same time, LDH level in supernatant and proportion of apoptotic cells of the3-MA+Iohexol group were significantly incresed compared with Iohexol group (P<0.05, P<0.05).Conclusions 1. Autophagy is upregulated during Iohexol (200mg I/ml) induced HK-2cells injury in a time manner.2. Inhibition of autophagy increased iohexol induced HK-2cell injury and apoptosis.3. Autophagy may play a protective role by eliminating HK-2cell injury and apoptosis during Iohexol treatment.