The mechanism of alopolysaccharide protecting ulceralive colitis

Abstract

The aim of this study is to explain the mechanism of alopolysaccharide protecting ulceralive colitis in cells and animal models. We divided this study into two parts: cell and animal research parts. In the cell research, HT-29 cells were divided into normal group, model group, aloe polysacchride group and positive drug group, the cell model was used by tumor necrosis factor- α (TNF-α) combine with LPS, detecting IL-6 concentration of difference groups by Elisa testing, Apoptosis of each group was detected by flow cytometry. We detected JAK2 and STAT-3 gene expressions of difference groups by RT-PCR. WB assay was used to detect the expression of JAK2, p-JAK2, STAT-3 and p-STAT3 protein in the cells of each group. In animal experiment, SD rats were divided into normal group, model control group, aloe polysaccharide group and positive drug group. A rat model of colitis was established with 2,4,6- three nitrobenzene sulfonic acid (TNBS). IL-6 concentrations of difference groups were measured by Elisa test, and compared the colon length of difference groups, H&E staining observation of colon tissue changes in each group. We observed JAK2, p-JAK2, STAT-3 and p-STAT3 protein expression in colon tissues by immuno histochemistry and measured JAK2 and STAT-3 gene expression of difference groups by RT-PCR. We found IL-6 concentration and cell apoptosis rate of Model group were significantly up-regulation compared with normal group (P<0.05, respectively) in the cell experiment. Compared with Model group, The IL-6 concentration and apoptosis rate of aloe polysaccharide group and positive drug group were significantly down-regulation (P<0.05, respectively). In the gene expression, JAK2 and STAT-3 expression of aloe polysaccharide group and positive drug group were higher than model group (P<0.05, respectively). JAK2, p-JAK2, STAT-3 and p-STAT3 protein expression of Aloe polysaccharide group and positive drug group were lower than model group. In animal experiment, compared with model group, The serum IL-6 concentration of aloe polysaccharide group and positive drug group were significantly decreased (P<0.05, respectively), colon length was improved by drug treated, The HE stain of aloe polysaccharide and positive drug group were significantly improved. In immuno histochemistry, The JAK2, p-JAK2, STAT-3 and p-STAT3 protein expression of aloe polysaccharide and positive drug group was significantly improved, The JAK2 and STAT-3 gene expression of aloe polysaccharide group and positive drug group were signivicantly lower than those of model group (P<0.05, respectively). Depending on the results, We supposed Aloe polysaccharide could effectively control the apoptosis of colonic tissues by inhibiting the JAK2/STAT-3 signaling pathway in vovo and vitro.

Keywords: Aloe polysaccharide; Apoptosis; JAK2/STAT-3 signaling pathway; Ulcerative colitis.