| Nonalcoholic fatty liver disease(NAFLD) is a kind of nonalcohol abuse, but pathological changes similar to nonalcoholic fatty liver disease(AFLD), he Patic steatosis and lipid storage for the characteristics of the clinical pathological syndrome. The disease s Pectrum of light to heavy includes simple steatosis, steatohepatitis(NASH), fatty liver pathological stage four fibrosis and fatty liver cirrhosis. The pathogenesis of NAFLD is very complex, the main theory to explain the pathogenesis of the disease is present for the "two hit" theory. The first blow mainly refers to the hepatocyte lipid deposition and insulin resistance and lipid metabolism disorder, the formation of simple fatty liver; two hit mainly refers to the oxidative stress caused by a variety of reasons and lipid peroxidation damage, caused by NASH. Despite the "two hit" theory has been widely accepted, causes the molecular mechanism of nonalcoholic fatty liver disease is still not clear.Mouse Cyp2a5 and human CYP2a6 have homology in amino acid sequence, plays an im Portant role in the coumarin, nicotine metabolism and exogenous drugs and carcinogens in the activation Process. The study found that the expression of Cyp2a5 is incremental viral, bacterial and parasitic hepatitis easily induced hepatocarcinogenesis in liver disease. At the same time, the amount of Cyp2a5 expression in mice of nonalcoholic fatty liver in the model group is increased. The transcription factor Nrf2, is a key factor in the cellular response to oxidative stress in. Nrf2 with the cytoplasmic protein Keap1 and antioxidant response element(antioxidant response element, ARE) interaction, induced expression of detoxification enzymes and downstream encoding antioxidant Proteins and II genes, including glutathione S transferase(GSTs), catalase(CAT), superoxide dismutase(SOD), heme oxygenase enzyme(HO1) etc.. Nrf2 is a key transcription factor regulating cell against foreign bodies and oxidative damage, Nrf2 activation barrier or deletion, can cause increased cell sensitivity to stressors. Nrf2 can reduce the sensitivity of the liver to oxidative stress, maintain stability and prevent the liver function of liver diseases, has a protective effect on liver damage, fatty liver, hepatic fibrosis and liver cancer etc.In this test the preliminary nonalcoholic fatty liver model of ICR rats were established as experimental animal, pathological changes of physiological were studied in liver injury nonalcohol when stimulated Cyp2a5 increment expression. Then the Nrf2 gene knockout ICR rats by nonalcoholic liver injury, the expression of Cy P2a5, determine the Cyp2a5 increment ex Pression whether dependent Nrf2 pathway, and to study the molecular mechanism of Nrf2 gene deletion and its action on the effects on nonalcoholic fatty liver disease process, further clarify the role of Cyp2a5 in non-alcoholic fatty liver in the Nrf2 pathway, clarify the increment in hepatic injury in regulating Cyp2a5 effect; analysis of nonalcoholic liver injury, Nrf2 and Cyp2a5 interactions.High fat diet after 8 weeks, mice serological results of wild type and gene deletion type display, compared with the control group mice, wild type and deficient mice in NAFLD model group TC, LDL, GLU, ALT and AST were significantly increased(P<0.01), ALP increased significantly(P<0.01 or P<0.05), TP decreased significantly(P<0.01), but TG and HDL did not change significantly(P>0.05); group mice compared with wild-type controls, TC and ALP gene deletion type mice increased significantly(P<0.01), HDL increased significantly(P<0.05), TP were significantly decreased(P<0.01), ALT decreased significantly(P<0.05), but TG, LDL, GLU and AST no significant change(P>0.05); compared with wild-type mice in NAFLD model group, genotype NAFLD of rats in model group HDL and ALP were significantly increased(P<0.01), TG, and ALT increased significantly(P<0.05), LDL were significantly decreased(P<0.01), TC and AST were significantly decreased(P<0.05), but TP and GLU changes not obvious(P>0.05).Pathological changes of liver display, control group mice liver fatty degeneration, morphology of liver cells is normal in mice, hepatic cord arranged in neat rows, the structure of hepatic lobule was normal, there was big and round nucleus cell central, no obvious fat droplets, the basic no inflammatory cells. The relative size of the mice in NAFLD model group liver nuclei uneven, fatty degeneration(vesicles and macrovesicular steatosis) and accompanied by necrosis of liver cells and inflammatory cells infiltration. Wild type mice with hyperlipidemia liver showed a small degree of microvesicular steatosis, gene deletion in hyperlipidemic mice liver Nrf2 showed microvesicular steatosis severe macrovesicular steatosis and gentle; oil red staining, compared to WT-ND, KO-ND in mice liver fatty droplets in a small amount of red dye; liver WT-HFD and KO-HFD the mice have obvious red lipid droplet.Effect of NAFLD on the peroxidation of hepatic antioxidant ability and lipid results display, high fat diet after 8 weeks, liver GSH, SOD, POD and MDA activity changes with the control group mice compared to wild type, and the gene deletion NAFLD model group in mouse liver GSH and SOD activity was significantly lower(P<0.05 or P<0.01), while POD and MDA activity increased significantly(P<0.05 or P<0.01). Compared with the wild type mice, 49% increased the activity of MDA gene deletion of NAFLD in the liver of mice in model group, but GSH, SOD and POD did not change significantly(P>0.05). Compared with the wild type mice in control group, SOD, POD and MDA genotype in the liver of mice increased significantly(P<0.05 or P<0.01), while the GSH activity decreased significantly(P<0.01). At the same time, the downstream target gene Nrf2 related changes the results showed, compared with the control group mice, wild type and gene deficient mice in NAFLD model group, the expression of-GCS, Nqo1, GSTA1 gamma HO-1 and m RNA increased significantly(P<0.05 or P<0.01), and gene deletion type model group mice in the NAFLD CAT and GCLC m RNA expressions were not obvious change(P>0.05). Compared with wild type mice in NAFLD model group, Nrf2 significantly reduced the volume of all the downstream target gene expression gene deletion type NAFLD model group mice(P<0.05 or P<0.01).Western blot, immunohistochemistry results showed, induced by high fat and fatty acid induced, compared with the control group, Nrf2 model group liver cytosol protein content decreased significantly(P<0.01); Nrf2 protein content in liver nuclei increased significantly(P<0.01), explain the high fat diet and fatty acid induced Nrf2 nuclear transfer.The results showed that effect of NAFLD on Cyp2a5 ex Pression in liver tissue. compared with the wild type NAFLD mice model of wild type mice in control group, the expression of Cyp2a5 Protein increased by 23%, a significant difference(P<0.05); gene deletion type NAFLD model mice with deficient mice compared to control group, the expression of Cyp2a5 Protein in liver of mice increased 13%; gene deficient mice(NAFLD group and control group) compared with wild type mice, the expression of Cyp2a5 protein were significantly decreased(P<0.01). Compared with the wild type NAFLD model mice, wild-type mice of control group the activity of Cyp2a5 increased 35%, a significant difference(P<0.01); gene deletion type NAFLD model mice with deficient mice compared to control group, the liver Cyp2a5 enzyme activity of mice increased 16%; and the genotype of mice liver the enzyme activity of Cyp2a5 was significantly lower than that of wild-type mice(P<0.01); immunohistochemistry results showed that, in the wild type WT-ND mice in control group, the positive expression of quantity liver cell line Cyp2a5 by few; high fat induced, apparent expression of Cyp2a5 WT-HFD in mouse liver around central vein in liver cells, expression was significantly higher than that of WT-ND mice(P<0.05). In control group, KO-ND gene deletion in mice, Cyp2a5 expression quantity is little; in KO-HFD mice Cyp2a5 positive expression, slightly higher than the KO-ND mice, but had no significant difference, based on the above results, showed that the expression of Cyp2a5 induced by high fat in the process, Nrf2 has a moderating effect on the Cyp2a5.The research results show that, the occurrence of oxidative stress in the liver closely related with high fat induced NAFLD disease; in the NAFLD disease process, expression of Nrf2 activated downstream of antioxidant factor can resist oxidation factor, protect the liver; Nrf2 involved in the regulation of Cyp2a5 expression of NAFLD in the course of a disease. |
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