The Role Of Uncoupling Protein 2 In Peroxidative Damage Of Non-alcoholic Fatty Liver Disease

Objective:To explore the effect of UCP2 in peroxidarion injury and protective effect of genipin and Vitamin E(VitE) on non-alcoholic fatty liver disease(NAFLD) by observing the gene and protein expression of UCP2, the changes of mitochondrial membrane potential and the levels of other related factors in vitro model.Methods:Immortalized normal human fetal liver cell line L02 was cultured and divided into 5 groups:control group(normal cultured for 72 h), model group(treated with palmitic acid for 72 h), drug A group(cells were treated with Vit E and palmitic acid at the same time for 72 h), drug B group(cells were treated with genipin and palmitic acid at the same time for 72 h), and drug C group(cells were treated with Vit E, genipin and palmitic acid at the same time for 72 h). Changes of lipid droplets in L02 cells were observed by optical microscope using oil red O staining. ALT, AST, GGT, TG, MDA and SOD in cell culture mediums were detected. Mitochondrial membrane potential were observed using Rhodamine 123 single-staining by flow cytometry(FCM). The expression of UCP2, NF-κB, TNF-αwere determined by RT-PCR and Western blot.Results:1. L02 NAFLD cell model was successfully established.2. Compared with control group, steatosis was significantly in model group cells; the levels of ALT, AST, GGT, TG and content of MDA were increased, activity of SOD was decreased in cell supernatants of model group;mitochondrial membrane potential was decreased; the gene and protein expression of UCP2, NF-κB and TNF-αwere significantly increased.3. The degree of steatosis in drug A, B, C group was lower than that of model group; the levels of ALT, AST, GGT, TG and MDA were reduced; mitochondrial membrane potential was increased; the gene and protein expression of UCP2, NF-κB and TNF-αreduced to some extent.The most particular effect was drug C group.Conclusions:1. The high expression of UCP2 is related to the peroxidative damage in NAFLD.2. NF-κB and TNF-αare involved in the occurrence of NAFLD.3. By inhibiting the expression of UCP2,genipin can increase the mitochondrial membrane potential,reduce the production of lipid peroxide,and lower the degree of steatosis in NAFLD cell model. 4. Vit E can alleviate the fatty degeneration of liver cells to some extent.But its effects of reducing the expression of UCP2 and elevating the mitochondrial membrane potential are not as good as genipin's.5. A combination of genipin and Vit E can lower the degree of steatosis in NAFLD cell model.Which may be refer to they are reduce peroxidation by acting on different targets,and the suppressed expression of NF-κB and TNF-αare involved in.