Effects And Molecular Mechanism Of Astragalus And Its Components On The Model Of Spleen Deficiency And Dampness Stagnancy In Rats

Objective: To study the effects of Astragalus and its components(flavonoid components, saponin components, polysaccharide components, aqueous extract components) on the model of spleen deficiency and dampness stagnancy in rats and to explore the molecular mechanism of Astragalus and its components on this TCM syndrome through detecting whole-gene expression in duodenal tissue in ras with the model. To find active substances behind the property and flavor of Astragalus and provide the scientific basis for the theory of property and flavor hypothesis.Methods: 1. The model of spleen deficiency and dampness stagnancy in rats was induced with high-fat and low-protein diet plus exhaustive swimming methods. The general condition, body weight, the index of gastrointestinal function and water metabolism, serological index were observed and used to evaluate the model.2. With the methods of Elisa, enzymic method, histomorphology, the changes of the serum gastrin levels, urine D-xylose excretion rate, gastric emptying rate, intestinal propulsive rate, water load index, blood lipid, serum protein and the morphology of the duodenum were detected in rats with the model after intragastric administration with Astragalus and its component groups.3. The gene chip technology was applied to study the differential gene expression of rats’ duodenal tissue among the groups, and to identify differential expressed gene, Clustering analysis, the enrichment dgree of gene ontology and Pathway were analysed using FunNet analysis platform.4. Real-time PCR was applied to detect the expression of Reg1 a, Aqp5, Trpm6, and Tff2 mRNA, to confirm the reliability of the gene chip results.Results: 1. Compared with that in rats in control group, the general condition became worse, the body weight and the times of autonomic activity significantly decreased, serum gastrin level and urine D-xylose excretion rate decreased( P <0.01, P <0.05), water load index increased( P <0.01), decreased urine output( P <0.01), TP, ALB, GLB and HDL-C decreased( P <0.05, P <0.01), CHOL and LDL-C increased(P <0.01) in rats in model group.2. Compared with that in rats in model group, the general conditions and the tissue morphology of duodenum were improved, the body weight and serum gastrin level were increased( P <0.05, P <0.01) in rats in Astragalus group and its components groups; the times of autonomic activity was increased in rats in Astragalus group, flavonoid, polysaccharide and aqueous extract components group( P <0.05, P <0.01); the urine D-xylose excretion rate, gastric emptying rate and intestinal propulsive rate were increased in rats in Astragalus group and polysaccharide components group( P <0.05, P <0.01), and the gastric emptying rate and intestinal propulsive rate were increased in rats in flavonoid components group( P <0.05, P <0.01); the urine D-xylose excretion rate was increased in rats in saponin components group( P <0.05); the water load index was decreased and the urine volume was increased in rats in Astragalus and its components groups( P <0.05, P <0.01); TP, GLB, HDL-C were increased and CHOL and LDL-C were decreased in rats in Astragalus group, polysaccharide components group and aqueous extract components group( P <0.05, P <0.01); HDL-C was increased, CHOL and LDL-C were decreased in rats in flavonoid components group(P <0.05); HDL-C increased in rats in saponin components group(P <0.05).3. According to the results of gene chip, there were 1275 differentially expressed genes in rats in model group as compared to blank control group. There were 688, 1204, 1361, 3181, 2419 differentially expressed genes in rats in Astragalus group, flavonoid components group, saponin components group, polysaccharide components group, aqueous extract components group as compared with that in rats in model group. 92 common differentially expressed genes were found among the medicated groups as compared with that in rats in model group.The molecular mechanism of spleen deficiency and dampness stagnancy was related to reduction of digestion, transport dysfunction, Amino acid metabolism disorder and low immune function. The changes in expression of genes affected many aspects of water metabolism, digestion and absorption(protein, mineral and fat), metabolism(serine, threonine, arginine, proline and arachidonic), and immune after administrated with Astragalus and its components.Conclusion: The TCM syndrome model of the spleen deficiency and dampness stagnancy in rats showed most the pathological characteristics and comply with this TCM syndrome. Astragalus and its components can improve the dysfunction state of spleen in rats with the model, this may reflect the “sweet in taste and warm in nature” of Astragalus. The molecular mechanism may be related to regulate the gene expression of water metabolism, digestion and absorption, metabolism and immune. Polysaccharide components may be the main active substance, when other componments may take effects to some extend.