Occurrence of oxidative stress and interventional effects of vitamin E on HepG2 steatosis model

Objective To establish hepatocyte steatosis model,explore the oxidative stress role of fatty acid mixtures in HepG2 cells and the effects of vitamin E on redox system of steatosis hepatocyte.Methods HepG2 cells were incubated with different gradient concentrations (0.125,0.250,0.500 and 1.000 mmol/L) of fatty acid mixtures (the ratio of oleic acid to palmitic acid was 2 to 1).The cell viability was detected by cell counting kit-8 assay.HepG2 cells were incubated with fatty acid mixtures at 0.5 mmol/L and 1.0 mmol/L,at 12,24 and 48 hour the cells were stained with oil red O staining and the content of triglyceride in the cells was tested.After the hepatocyte steatosis model established,the content of lipid peroxidation product malondialdehyde(MDA) and the level of superoxide dismutase (SOD) and reduced glutathione (GSH) were detected.Then the cells were intervened by vitamin E,and the effects of vitamin E on MDA,SOD and reduced GSH were examined.t test was used for two groups of measurement data comparison.Results With the extension of time and increased concentration of fatty acid mixtures,the number of lipid droplet in HepG2 cells under microscope and the content of triglyceride gradually increased.After treated for 24 hours,the content of MDA in HepG2 cells treated with fatty acid mixtures at 0.5 mmol/L and 1.0 mmol/L increased 56.3％ (t=4.28,P=0.012 9) and 66.6％ (t=6.87,P=0.002 4) compared with control group,the level of reduced GSH decreased 30.6 ％ (t=4.24,P=0.013 3) and 43.7％ 0=6.13,P=0.003 6) compared with controlgroup and the differences were statistically significant.The level of SOD in cells treated with 1.0 mmol/L fatty acid mixtures decreased 39.2％ (t=3.20,P=0.032 8) compared with control group at 24 hour and with 0.5 mmol/L decreased 40.6％ (t=8.27,P=0.001 2) at 48 hour compared with control group and the differences were statistically significant.After intervened by vitamin E for 24 hours and 48 hours,the content of MDA in steatosis HepG2 cells decreased 31.8％ (t=4.00,P=0.016 1) and 37.5％ (t=8.27,P=0.004 2) compared with control group,the differences were statistically significant.After intervened for 12,24 and 48 hours,the level of SOD increased 1.9％,14.5％ and 50.5％; the level of reducedGSH increased 4.1％,33.2 ％ and 52.0 ％.Conclusions The hepatocyte steatosis model successfully induced by fatty acid mixture at concentration of 0.5 mmol/L and the ration of oleic acid to palmitic acid is 2 to 1.There is remarkable oxidative stress in steatosis HepG2 cells.Antioxidant vitamin E could reduce oxidative stress to certain degree. Key words: Fatty liver;  Tumor cells, cultured;  Oxidative stress;  Vitamin E