Effects And Mechanisms Of Sulfated Polysaccharides From Pacific Abalone On High Fat Diet-induced Metabolic Syndrome In Mice

With the development of the times,people's material level has been greatly improved,and dietary intake has been varied.In particular,foods rich in high-fat and high-sugar are popular with people.Excessive consumption of high-sugar and high-fat foods can lead to The incidence of metabolic syndrome such as obesity,hyperlipidemia,and diabetes has surged.Studies have shown that increasing the intake of polysaccharides can effectively improve the body's health and inhibit the occurrence and development of metabolic syndrome.Abscisic acid sulfate polysaccharide(AGSP),an acidic heteropolysaccharide,has good biological activity in immune regulation,anti-oxidation,anti-coagulation and other aspects,but its effect on the metabolic syndrome induced by high-fat diet and its mechanism is not yet clear.In order to clarify the mechanism of AGSP activity,this paper first studied the metabolic properties of AGSP in vivo.The results show that AGSP is difficult to be degraded by the complex enzyme system and environment in the upper digestive tract of the body,and it can reach the colon completely and is utilized by the gut microbiota.In vitro experiments confirmed that AGSP can promote the beneficial of gut microbiota such as Bacteroidetes and Bifidobacteria in Intestine.It was initially confirmed that AGSP could play a role in vivo by regulating gut microbiota.Taking high-fat mice as the research object,this paper studied the effect of AGSP on metabolic syndrome induced by high-fat diet and its mechanism.AGSP can reduce body weight gain and fat accumulation caused by high-fat diet,improve lipid metabolism reaction in mice,and reduce damage to organs.AGSP repaired the imbalance of gut microbiota caused by high-fat diets,improved the use of nutrients,increased the expression of short-chain fatty acids,and thus affected the expression of lipid-related genes in adipose tissue.The above results show that AGSP can improve the composition of gut microbiota and improve the symptoms of obesity and lipid imbalance caused by high-fat diets.The biological activity of polysaccharides is closely related to its degree of polymerization,monosaccharide composition,and modifying groups.However,the effect of polysaccharide intake on its activity has not been reported.In this dissertation,the effect of diet on the biological activity of AGSP was investigated.The results showed that the dietary pattern had no decisive influence on the activity of AGSP,but the effect of intragastric administration on improving the physical and chemical indexes of high-fat mice was better than that of free diet.The improvement of gut microbiota by AGSP was not affected by the mode of ingestion as a whole,but subtle differences could be observed in some microorganisms,resulting in differences in the overall structure of the intestinal flora due to dietary differences.The biological activity caused a slight effect.The biological activity of AGSP is closely related to its regulation of gut microbiota,but the mechanism of AGSP regulating gut microbiota is not clear.In this dissertation,Bacteroides was used as the entry point to obtain different strains of Bacteroidetes in vitro and the characteristics of AGSP were analyzed.The results showed that the ability of Bacteroides to use AGSP has obvious strain specificity,and some strains cannot directly use AGSP.The composition of gut microbiota in different individuals is similar but not identical,and the strain-specificity of polysaccharide utilization may be one of the factors that cause the same polysaccharide to have different effects on different individuals.