Role Of Autophagy In Contrast Media Induced Renal Tubular Epithelial Cell Apoptosis And Effects Of Atorvastatin

[Objective] To investigate the Role of autophagy in contrast media induced renal tubular epithelial cell apoptosis and effects of Atorvastatin.[Methods]1.Human renal tubular epithelial cell(HK-2) was cultured as the research object in vitro.HK-2 cells were exposed to Iohesol at different concentration for 4h. HK-2 cells were exposed to Iohesol at 80 mg I/l for variable incubation times. The change of cell proliferation was detected by MTT assay.Using western blot to detect the expression of LC3 and Beclin1 to observe autophagy of HK-2 cell induced by contrast media.2.The cells were incubated with Atorvastatin(10-7mol/L) for 24 h and then exposed to Iohexol(80 mg I/L)for 4h. The change of cell proliferation was detected by MTT assay.The apoptosis level of HK-2 cells was examined by flow cytometry. The expression of LC3 and Beclin1 was examined by Western blotting.3.HK-2 cells were divided into six groups(control group, Iohexol group, Atorvastatin +Iohexol group, the NC- si RNA + Iohexol group, Beclin1 si RNA +Iohexol group,Beclin1-si RNA +Atorvastatin + Iohexol group). The cells were incubated with or without of Atorvastatin pretreatment and then exposed to Iohexol(80 mg I/L)for 4h that which is to investigate the role of autophagy in Atorvastatin pretreatment to protect the apoptosis of HK-2 cells induced by contrast media. The change of cell proliferation was detected by MTT assay. The apoptosis level of HK-2 cells was examined by flow cytometry. The expression of LC3 and Beclin1 was examined by Western blotting.[Results]1.CM group showed a lower survival rate(P < 0.05), a higher apoptosis rate(P < 0.01)and higher expression of LC3, Beclin1 proteins(P < 0.05) compared with the negative control group;ATO+CM group showed a higher survival rate(P < 0.05), a lower apoptosis rate(P < 0.01) and higher expression of LC3, Beclin1 proteins(P < 0.05)compared with the the CM groups(P < 0.05).2.Beclin1 si RNA + CM group and Beclin1 si RNA + ATO + CM group showed significantly lower expression of LC3 than NC- si RNA + CM group(P < 0.05).Whereas no difference was found in the expression of LC3 between ATO + Beclin1 si RNA + CM group compared with Beclin1- si RNA + CM group.3.Beclin1 si RNA + CM group and Beclin1 si RNA + ATO + CM group showed higher apoptosis rate(P < 0.05) than NC- si RNA + CM group. The different of apoptosis rate between ATO + Beclin1 si RNA + CM group compared with Beclin1- si RNA + CM group there were no statistical significance(P > 0.05).4.Beclin1 si RNA + CM group and Beclin1 si RNA + ATO + CM group showed lower survival rate compared with the NC- si RNA + CM group(P < 0.05).The different of cells proliferation between ATO + Beclin1 si RNA + CM and Beclin1 si RNA + CM group were no statistical significance(P > 0.05).[Conclusion]1. Atorvastatin can further enhance autophagy, increase the cell proliferation and reduce the apoptosis.2. Inhibition of Beclin1 gene expression increased the cell apoptosis from Iohexol induces.3. Inhibition of Beclin1 gene expression abrogated the protective effects of Atorvastatin on Iohexol-induced apoptosis on HK-2 cell.