| Obesity is a metabolic disease associated with gut microbiota and low-grade chronic inflammation.Research has shown that obesity and gut microbiota are closely linked and that disorders of gut microbiota can lead to low-level chronic inflammation and abnormal lipid metabolism,leading to obesity.Diet has a very important impact on the gut microbiota;therefore,it is important to find or develop safe and effective dietary additives to improve and prevent obesity.Tongjiang Tremella fuciformis is a medicinal and edible fungus;polysaccharide(TP)is the main active component,which has a variety of biological activities,such as hypoglycemic and hypolipidemic.However,the anti-obesity effects and potential mechanisms of TP have never been reported.1.Firstly,the polysaccharide of Tongjiang Tremella fuciformis was extracted as well as the main chemical components of the polysaccharide were analysed.The results showed that Tongjiang Tremella fuciformis polysaccharide yield was about 9.8% using the hot water extraction method.The relative molecular masses of the Tongjiang Tremella fuciformis polysaccharides obtained after preliminary isolation and purification ranged from 10.07 to66.29 k Da.Tongjiang Tremella fuciformis polysaccharide was composed of Man,Rha,Glc A,Glc,Gal,and Xyl in a molar ratio of 15.95:0.31:2.47:1.20:3.18:1.72.The results showed that Tongjiang Tremella fuciformis polysaccharide was a mannose-based heterosaccharide,and its monosaccharide composition was similar to the previously reported Tremella polysaccharide,however,there are differences in composition ratios.2.A model of obesity was constructed using C57BL/6J mice to research the effect of Tongjiang Tremella fuciformis polysaccharide on the prevention and improvement of obesity in mice fed a high-fat diet.The mice were divided into normal diet group(NCD),NCD＿TP＿H group,HFD group,HFD＿TP＿L group and HFD＿TP＿H group.At week 12,mice were sacrificed,changes in obesity-related parameters were measured and recorded,and tissue sections of liver,epididymal fat and perirenal fat were observed to assess the effects of Tongjiang Tremella fuciformis polysaccharide in preventing and improving obesity.Studies have shown that Tongjiang Tremella fuciformis polysaccharide can inhibit high-fat diet-induced weight gain and fat accumulation in mice,and reduce blood glucose,hyperlipidemia and inflammatory responses.3.The effect of Tongjiang Tremella fuciformis polysaccharide on the diversity,composition and structure of mice gut microbiota was assessed by 16 S r RNA high-throughput sequencing and corresponding bioinformatics analysis.The results showed that Tongjiang Tremella fuciformis polysaccharide could improve the reduction of gut microbiota diversity in mice under a high-fat diet and reshape the gut microbiota structure in obese mice.Tongjiang Tremella fuciformis polysaccharide also improved gut microbiota disorders by reducing the Firmicutes/Bacteroidetes ratio and modulating the relative abundance of specific gut microbiota.The antiobesity and gut microbiota-modulating effects of Tongjiang Tremella fuciformis polysaccharide could be transferred to HFD-fed mice via faecal microbiota transplantation(FMT),confirming that the gut microbiota was one of the targets of Tongjiang Tremella fuciformis polysaccharide for obesity inhibition.4.By gas chromatography analysis-mass spectrometry(GC-MS)and enzyme-linked immunosorbent assay(ELISA),it was found that Tongjiang Tremella fuciformis polysaccharide increased the production of short-chain fatty acids and the secretion of intestinal hormones in faeces.The expression of the relevant genes and proteins was then verified by q PCR and Western Blot.It was found that Tongjiang Tremella fuciformis polysaccharide could regulate the secretion of intestinal hormones,increase the feeling of satiety and reduce appetite in mice,leading to decreased food intake.It was finally confirmed that Tongjiang Tremella fuciformis polysaccharide could regulate the micmicrobial gut-brainis to suppress obesity.The results in animal experiments showed that Tongjiang Tremella fuciformis polysaccharide has a positive effect on the prevention and improvement of obesity in mice in terms of weight reduction,inhibition of fat accumulation,and improvement of glucolipid metabolism and inflammatory response.It is tentatively hypothesized that the anti-obesity effect of Tongjiang Tremella fuciformis polysaccharide is closely related to the gut microbiota,and the experimental results also indicate that Tongjiang Tremella fuciformis polysaccharide can increase the diversity of gut microbiota and improve the disorder of gut microbiota.The resultsthe of GC-MS method to determine the content of short-chain fatty acids in faeces and the expression of related genes and proteins revealed that Tongjiang Tremella fuciformis polysaccharide exerts its weight loss effect by regulating the microbe-gut-brain axis. |
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