| As a major kind of chronic disease today,obesity is prevailing all over the world.In recent years,obesity have been verified to be closely related to gut microbiota.And there exists such a hypothesis that systemic chronic low-grade inflammation induced by intestinal dysbiosis triggers metabolic diseases,such as obesity.Polysaccharides,as one of the abundant and structurally complex components of the diets,cannot be directly digested and absorbed by the human body,but can be utilized by gut symbionts to provide themselves essential energy.Therefore,polysaccharides play an important role in maintaining intestinal microbial homeostasis and protecting the intestinal barrier,and thus they are commonly known as "prebiotics".At present,it has been reported that certain polysaccharides prevented the development of obesity through some microflora-related mechanisms.In this paper,we chose a kind of hemicellulose polysaccharide,derived from bamboo shaving polysaccharides(BSP),as the research object,and explored their roles in prevention of diet-induced obesity and inhibition of the accomplying chronic systemic inflammation,as well as the modulation of intestinal flora.(1)Two doses of BSP,BSP200 and BSP400,were used to treat mice fed with high-fat diet(HFD)through dietary supplementation.The phenotypic changes of mice were observed during the process of feeding,and after 8 weeks,obesity-related biochemical indicators of mice were measured.The results showed that both of low and high doses of BSP could significantly(p<0.05)prevent overgrowth of HFD-fed mice.And the high dose inhibited excessive accumulation of body fat around the epididymis and the triglyceride(TG),total cholesterol(T-CHO),low-density lipoprotein cholesterol(LDL-C)and free fatty acid(FFA)levels in serum of HFD-fed mice,but it did not affect high-density lipoprotein cholesterol(HDL-C)level in serum.And daily food intake of mice were not affected.In addition,BSP also improved the insulin sensitivity of HFD-fed mice.(2)The effect of BSP on the chronic inflammation induced by HFD in mice was investigated using the methods of fluorescence quantitative PCR and enzyme-linked immunosorbent assay(ELISA),and the structural changes of colonic epithelial cells were observed by transmission electron microscope(TEM).The results showed that dietary intervention of BSP,especially the high dose,could reduce the mRNA expression of pro-inflammatory cytokines,TNF-?,IL-1? and IL-6 in adipose tissue,and lower the level of lipopolysaccharide(LPS),a potential triggering factor of inflammation,in serum of HFD-fed mice.Moreover,BSP effectively inhibited the damages of the villus of colonic endothelial cells,tight junctions between these cells,and intracellular mitochondria,which caused by HFD.(3)Illumina Miseq PE250 high-throughput sequencing platform was employed for 16S rDNA sequencing of flora in mice feces which collected after feeding for 8 weeks,and the bioinformatics analysis of sequencing data was then performed.The results showed that the dietary intervention of BSP not only increased the community diversity of intestinal microflora in HFD-fed mice and the similarity of the OTU composition of the intestinal microflora from HFD-fed mice to that of NC-fed mice,but also reversed the increase of the ratio of the Firmicutes to Bacteroidetes(F/B ratio)in relative abundance caused by the HFD.In addition,BSP enhanced the abundance of some beneficial microbes in the intestinal tract,such as Akkermansia muciniphila and Lactobacillus,and also inhibited the growth of harmful bacteria,like Enterobacter and Desulfovibrio.However,both high and low doses of BSP failed to rescue the abundance of Bifidobacterium.Consequently,this in vivo study indicated that dietary supplement of BSP with the doses of 200?400 mg/kg.bw presented a favourable intervention effect on diet-induced obesity of mice,which manifested by the prevention of diet-induced excessive growth of body weight,enhancement of insulin sensitivity and alleviation of chronic systemic inflammation,as well as the improvement of gut microbiota.Therefore,this paper further speculated that bamboo-shaving polysaccharides(BSP)might prevent diet-induced obesity and its related chronic systemic inflammation partly through improving gut microbiota. |
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