Abstract: Objective To analyze the lycium barbarum polysaccharides on hydroperoxide-induced autophagy of renal tubular epithelial cells（human kidney,HK-2） and the activation of extracellular regulated protein kinases（ERK）/mammalian target of rapamycin（mTOR） pathway in cells,and to explore the mechanism of lycium barbarum polysaccharides in improving oxidative damage. Methods The HK-2 cells were cultured in vitro and arranged into control group,lycium barbarum polysaccharide group,oxidative stress group and treatment group according to different treatment methods. The control group was given cell culture medium. The lycium barbarum polysaccharide group was given cell culture medium containing lycium barbarum polysaccharide. The oxidative stress group was given cell culture medium containing hydrogen peroxide. The treatment group was firstly incubated with lycium barbarum polysaccharide cell culture solution for 24 hours,and then added hydrogen peroxide for 30 minutes. The treatment time of each group was the same. The growth state of cells in each group was observed. The cell viability test box was used to analyze the survival rate of cells in each group. The content of malondialdehyde（MDA） in the cytoplasm and the activity of superoxide dismutase（SOD） were analyzed by colorimetry. The contents of cytoplasmic autophagy protein microtubule-associated protein light chain 3（LC3） and ERK/mTOR pathway related proteins ERK,p hosphorylation ERK（p-ERK）,mTOR and phosphorylation mTOR（p-mTOR） were evaluated by Western blot. Results In contrast to control group,the lycium barbarum polysaccharide group had no significant difference in cell growth status,survival rate,MDA content and SOD activity in the cytoplasm,the content of autophagy protein LC3 and ERK/mTOR pathway related proteins ERK,p-ERK,mTOR and p-mTOR（all P>0.05）. In the oxidative stress group,the number of cells shrinkage and suspension was more,the survival rate[（51.16±4.85）%] decreased,MDA[（4.78±0.81）mmol/L] increased,SOD[（10.11±1.17）U/L] decreased,the intracellular LC3Ⅱ/LC3Ⅰ（0.391±0.058） decreased,p-ERK/ERK（1.526±0.185）,and the p-mTOR/mTOR（1.423±0.174） increased（all P<0.05）. In contrast to oxidative stress group,treatment group had better cell status,less suspension,higher survival rate[（86.29±4.55）%],lower MDA[（2.22±0.46）mmol/L],higher SOD[（18.25±2.33）U/L],higher intracellular LC3II/LC3 I（0.846±0.091）,lower p-ERK/ERK（0.906±0.127）,and lower p-mTOR/mTOR（0.820±0.092）（all P<0.05）. Conclusion The lycium barbarum polysaccharide can inhibit the ERK/mTOR signal pathway in HK-2 stimulated by hydrogen peroxide,enhance the autophagy of cells,raise the survival rate of cells and improve their oxidative damage.

Key words: Lycium barbarum polysaccharide, Autophagy, Renal tubular epithelial cells, Extracellular regulated protein kinases ERK/Mammalian target of rapamycin signal pathway