Changes Of NOX4 And Nrf2 Expression In Liver Tissues During The Formation Of Liver Fibrosis

Objective:To observe the dynamic changes of the expression of reduced nicotinamide adenine dinucleotide phosphate oxidase 4（NOX4）and nuclear factor-E2-related factor 2（Nrf2）in the liver tissue of rats during the formation of liver fibrosis,and to explore the role of both in the formation of liver fibrosis in order to provide an experimental basis for the treatment of liver fibrosis.Methods:Thirty-four healthy male SD rats（180～210）g were randomly divided into two groups:normal control group（n=6）and model group（n=28）.During the experiment,two rats in the model group died at the end of the fifth and seventh week.Model group was subcutaneously injected with 40%CCl₄oil（twice a week,the dosage was calculated according to the body weight of the experimental rats,the initial dose was 5ml/kg,then changed to 2ml/kg,weighed once a week and the dosage was adjusted according to body weight）;Normal control group was injected subcutaneously with the same dose of oil until the end of the experiment.Rats in the two groups were given normal diet.Six rats in the normal control group and the model group were sacrificed at the end of the second,fourth,sixth and eighth week,respectively,and liver tissue was kept for later use.Hepatic tissues of rats in each group were routinely stained with HE and Masson to observe the pathological changes and fibrosis of liver tissues,and the expression of NOX4 and Nrf2positive proteins in liver tissues were detected by immunohistochemistry.Results:1.Histopathological results:HE and Masson staining of liver tissue showed that liver cell cords were arranged neatly in the normal control group,and the structure of liver lobules was complete,without obvious inflammatory cell infiltration.Model group early visible liver cell edema,ballooning change and fat,and longer duration of building damage liver cell gradually increase,accompanied by varying degrees of necrosis,hepatic lobule structure damage increase gradually,fiber cords and broadening gradually appeared,to 8weekend visible part structure of hepatic lobule is not complete,fiber interval surrounding the formation of false flocculus,a large number of inflammatory cells infiltration.2.Positional expression of NOX4 and Nrf2 positive proteins in liver tissue:the color of NOX4 positive proteins in the cytoplasm of liver cells,fibrous septum and part of vascular endothelial cells was brownish yellow,while the color of Nrf2 positive proteins in the cytoplasm of liver cells was brownish yellow.The expression of NOX4 and Nrf2positive proteins in liver tissue of normal control group was less,but with the prolonging of modeling time,the expression of NOX4 and Nrf2 positive proteins in liver tissue of model group increased gradually at 2,4,6 and 8 weeks.3.Quantitative expression of NOX4 and Nrf2 positive proteins in liver tissue:The mean optical density of NOX4-positive protein in liver tissue of model group at 2,4,6 and8 weeks（0.132±0.005,0.158±0.010,0.170±0.010,0.212±0.007）was higher than that of normal control group（0.095±0.008）,respectively.The difference was statistically significant（P<0.05）.The average optical density of Nrf2-positive protein（0.115±0.007,0.129±0.006,0.144±0.008,0.154±0.008）was higher than that of normal control group（0.073±0.005）,and the difference was also statistically significant（P<0.05）.4.Pearson correlation analysis showed that the average optical density value of NOX4positive protein was positively correlated with the average optical density value of Nrf2positive protein（r=0.902,P<0.05）.Conclusion:In the formation process of CCl₄-induced liver fibrosis,the expression of NOX4 and Nrf2-positive proteins in rat liver tissue increased,and correlation analysis showed that they were positively correlated,indicating that both of them were involved in the occurrence and development of liver fibrosis.