Research On The Effect Of Konjac Oligosaccharides Intervention On Obesity Induced By High-fat Diet

In this study,konjac oligosaccharides was added to high fat diet to investigate the regulation effects of konjac oligosaccharide on the body weight,liver index,blood lipid and oxidative stress,gut microbiota induced by high fat diet.RT-PCR was adopted to measure related gene expression and preliminarily discussed the mechanism.Thirty-six male Kunming mice were randomly divided into normal diet group,high fat diet group and oligosaccharide intervention group.The effects of konjac oligosaccharides on obesity induced by high fat diet were evaluated through measuring the indexes of body weight,liver index,fat ratio,lipid level,oxidative stress level,gut microbiota,lipidomics,fecal short-chain fatty acids(SCFA)and other related indices.First,the body weight,liver index,body fat ratio,blood glucose and other indicators were measured,and the histopathology of liver was also observed.The results showed that the intervention of konjac oligosaccharides could inhibit the accumulation of body fat to a certain extent.Second,the related genes of lipidomics,blood lipids and oxidative stress levels,glucose and lipid metabolism,and oxidative stress were measured,respectively.Compared with high fat group,the ingestion of konjac oligosaccharides significantly improved the lipid components and significantly regulates serum lipids in high-fat diet mice.At the same time,the study also found that the addition of oligosaccharides can inhibit the generation of malondialdehyde(MDA)in mice.Compared with high fat group,the ingestion of konjac oligosaccharides significantly up-regulated the expression of mRNA in the genes associated with fatty acid decomposition(CPT,PPARγ),low density lipoprotein receptor(LDL-R),glucose metabolism of liver and insulin secretion related genes(GK,GLUT2,Insulin2).The expression of mRNA in the cholesterol synthesis-associated gene(HMG-CoA-R)was significantly down-regulated.Therefore,compared with high fat group,konjac oligosaccharides can regulate serum lipid levels and improve lipid metabolism caused by high-fat diet in mice.At the same time,Konjac oligosaccharides can increase the levels of serum antioxidant enzyme(GSH-Px and SOD)by up-regulating the mRNA expression of anti-oxidant genes(GCLC,GSTpil,Mn-SOD)and can also down-regulate the mRNA expression related to the inflammatory genes(MMP-7,VCAM-1),thus inhibiting the oxidative stress caused by high-fat diet.Finally,HiSeq high-throughput sequencing revealed that high-fat diet could result in more Firmicutes and fewer Bacteroidetes in the phylum level.High-fat diets not only affected the changes of intestinal microbes,but also reduced the content of short-chain fatty acids(SCFA),the metabolites of intestinal microbes.The study found that konjac oligosaccharides intervention could reduce the proportion of Firmicutes and Bacteroides in the phylum level,and could increase the number of beneficial microorganisms,and could reduce the content of pathogenic bacteria,then improving short-chain fatty acids in the feces compared with high fat group.This shows that konjac oligosaccharide intervention can make the body’s intestinal system in a better state,thereby maintaining the health of the body.