Study On The Function Of MAPK In The Process Of Liver Fibrosis Induced By Sodium Arsenite And The Effects Discussion Of Dictyophora Polysaccharides

Objective: Discussion the function of MAPK signal transduction pathways on liver fibrosis induced by sodium arsenite, and the influences of Dictyophora polysaccharide on the function of MAPK in liver fibrosis. Methods: 1. Animal experiments: Rats were exposed to various concentratios of sodium arsenite to establish animal model of hepatic fibrosis. Immunohistochemical assay was used to detect the protein expression of MKK1, p-ERK, MKK3, p-P38, MKK4, p-JNK at the end of exposure time; Using different concentrations of Dictyophora polysaccharide to intervene the middle concentration sodium arsenite exposed rats on infected en points, Immunohistochemical assay was used to detecte indexes above mentioned, to investigate if Dictyophora polysaccharide antagonizing liver fibrosis has something to do with MAPK signal pathway. 2. Cell experiments : Using arsenic induced HSC activation cell model to detecte the role of MAPK pathway in activation passage of HSC. MTT assay was used for detections of HSC cell survival in different concentrations of sodium arsenite poisoning and MAPK inhibitors intervention environments, working concentrations of sodium arsenite and MAPK inhibitors were made according to the MTT assay results. Western blot was used to assay the protein expressions of α-SMA in the passage of HSC. HSCs was divided into model group and model+MAPK group, using western blot to assay the protein expression of MKK1/2, p-ERK, MKK3/6, p-P38, MKK4, p-JNK, α-SMA. Results: 1. In vivo experiments: The protein expressions of MKK4, p-JNK, p-P38 and MKK3 were all significantly increased(P<0.05) in rats liver tissues of every exposured groups with the increasing concentrations of sodium arsenite, expressions of MKK1 and p-ERK were significantly decreased(P<0.05) compared with the control group. At the end of the Dictyophora polysaccharide intervention time, the protein expressions of MKK4, p-JNK, MKK3 and p-P38 were significantly decreased(P<0.05) in rats liver tissues of every intervention group with the increasing concentrations of Dictyophora polysaccharide.The expression of protein MKK1/2 and p-ERK in every intervention group were significantly decreased(P<0.05) compared with the exposure group. 2. In vitro experiments : The working concentrations of sodium arsenite were 25μmol/l, 50μmol/l, 75μmol/l, the working concentrations of SP600125 and SB203580 were the same of 10μmol/l, PD98059 was 50μmol/l according to the MTT results. In the condition of passage and sodium arsenie exposure, the protein expression of α-SMA was both significantly increased(P<0.05) with the increasing of passage number and sodium arsenite concentration, the protein expression of α-SMA was significantly decreased in every intervention-exposure group compared with the non-intervention-exposure group after intervened by MAPK pathway inhibitors. The protein expression of p-JNK, MKK1/2, p-ERK and p-P38 of HSCs were significantly increased(P<0.05) with the increasing concentration of sodium arsenite, expression of MKK4 and MKK3/6 were significantly decreased(P<0.05) with the increasing concentration of sodium arsenite. The protein expressions of MKK4, p-JNK, MKK1/2, p-ERK, MKK3/6 and p-P38 of HSCs were significantly decreased(P<0.05) after intervened by MAPK pathway inhibitors compared with non-intervention-exposure group. Conclusion: Sodium arsenite can induce activation of HSC through the MAPK signal pathway, and the ERK pathway plays the most important role, Dictyophora polysaccharide has an antagonistic effect on the process of HSC activation and liver fibrosis development induced by sodium arsenite through regulating the up-downstream protein expression of the MAPK signal pathway.