The Study About The 1,25（OH）₂-D₃ Affects Smurf2 Expression To Inhibit Liver Fibrosis In Rats

Purpose:Liver fibrosis is an intermediate process in which the liver chronic inflammation,liver cirrhosis and liver cancer are caused by diseases such as viruses,drugs,alcohol,parasites,immunity,and metabolic abnormalities.It is a process in which excessive repair of liver tissue leads to scar formation.In the European Union,0.1%of the population is affected by cirrhosis,about 170,000 people die as a result of those whose liver tissue pathological changes are severe^[1].China has a big population affected with hepatitis.Liver disease is one of the most common diseases,accounting for about 10%of the total population are hepatitis B virus carriers.Liver fibrosis and cirrhosis bring huge economic burden to the society.When general treatment can not meet the needs of the disease,liver transplantation becomes the last choice^[2].However,the lack of supply,the high cost of transplantation and the impact of receptors and other factors limit the application of this technology.Studies have reported that during the induction of liver fiber experiments,if the injury stops,liver fibrosis can be restored^[3].Clinical results show that some liver fibrosis phenotype caused by chronic liver diseases can be resolved after self-control^[4].Therefore,it is of great significance to study the mechanism of liver fibrosis formation and to find a way to reverse this process.After the liver is damaged,hepatic stellate cells（HSC）are transformed into myofibroblasts,producing a mass of extracellular matrx.A variety of cellular signaling pathways are involved in the activation and proliferation of HSCs,with the TGF-β/Smad pathway being considered the most important pathway.Smurf2（Smad ubiquitination regulatory factor 2）may play an important regulatory role.Studies have shown that Smurf2 is an E3 ligase of Smad,which specifically binds ubiquitin molecules to the corresponding substrate,degrades proteins to regulate the classical signaling pathway,and works on inhibiting liver fibrosis.Studies have shown that Smurf2 can down-regulate Smad7 by ubiquitination to regulate TGFβ/Smad signaling pathway^[5-6].Previous studies by our team has found that 1,25（OH）₂-D₃ inhibited HSC proliferation,promoted apoptosis,and slowed the progression of liver fibrosis^[7].1,25（OH）₂-D₃ can reduce TGF-β1expression^[8].The specific mechanism is not clear.In this study,we investigate the possible mechanism of Smurf2 expression induced by active vitamin D in liver fibrosis process,by observing the changes of Smurf2,and provided theoretical basis for further application in clinic.Methods:48 SD rats were randomly divided into 4 groups:Model control（Olive oil）、Model（50%CCl₄ Olive oil solution）、Treatment control（50%CCl₄ Olive oil solution+olive oil garage）、Treatment（CCl₄ Olive oil solution+1,25（OH）₂-D₃ 3ng/100g·d olive oil solution by garage）.After 8 weeks,the liver tissue was taken and the histopathological changes and fibrosis degree were observed by Masson staining.The expression of Smurf2 protein in liver tissue of each group was detected by Western blot.The Smurf2 mRNA of each group was detected by real time-PCR.Data were expressed as（`x±s）,test methods:one-way analysis of variance was used for comparison between groups,and LSD-t test was used for further multiple comparisons.P<0.05 was considered statistically significant.Results:1.Pathology showed:The liver fibrosis of the model group and the treatment group was significantly changed.The degree of liver fibrosis in the treatment group was significantly reduced compared with the model group and the treatment control group;2.Smurf2 protein expression:the expression of Smurf2 protein in the Treatment group was higher than that in the Model group and the Treatment control group（P<0.05）,and the difference was statistically significant.The expression of the Treatment group was lower than that of the Model control group.3.Smurf2 mRNA expression:the test showed that the Treatment group was higher than the model group and the Model control group.Conclusions:1.1,25（OH）₂-D₃ can significantly reduce the degree of liver fibrosis in rats;2.Compared with the model group,the Smurf2 protein and Smurf2 mRNA were significantly increased in the 1,25（OH）₂-D₃ treatment group,suggesting that 1,25（OH）₂-D₃ may play a role in inhibiting liver fibrosis by enhancing the expression of Smurf2 gene.