Modulation Effects Of Konjac Glucomannan On High-Fat Diet-Induced Metabolic Disorders

The main functional active component of konjac is the konjac glucomannan(KGM),which has a high medicinal and edible value.In recent years,some progress has been made in the prevention and treatment of obesity by KGM.However,the mechanism of action mostly stays at the level of increasing the sense of satiety.In this study,the mechanism of KGM intervention on metabolic disorder induced by high fat diet was preliminarily discussed,and whether it was dose-dependent or not.With the aid of 16s RNA high throughput sequencing and lipidomics,we hope to make a systematic explanation from the perspectives of metabonomics and molecular level so as to provide a scientific basis for the further development and utilization of KGM.Firstly,obesity model was established by high fat diet.After modeling successfully,they were divided into four groups:normal control group(NC),high fat group(HF),low dose konjac glucomannan intervention group(L-KGM)and high dose konjac glucomannan intervention group(H-KGM).They were fed basic diet,high fat diet and intervention feed(3%and 7%konjac glucomannan instead of basic diet respectively).The changes of body weight,food intake,blood glucose,insulin level,lipid metabolism,oxidative stress,liver function index,gut microbiota and short chain fatty acid(SCFAs)were observed after 6 weeks of continuous intervention.The results showed that compared with HF group,KGM could control the weight gain of obese rats.The effect of H-KGM on blood glucose and insulin resistance was more obvious(p<0.01).The hyperlipidemia state was regulated by regulating the lipid composition of H-KGM,and the disorder of lipid metabolism was ameliorated.After intervention,there was a reduction in level of maondialdhyde(MDA),and the L-KGM group showed significant difference(p<0.01).The level of total superoxide dismutase(T-SOD)tends to increase.Meanwhile,there was a increasion in level of glutathione peroxidase(GSH-PX),and the H-KGM group showed significant difference(p<0.01).Liver weight,liver index and body fat ratio were significantly decreased in rats.The content of liver total cholesterol(TC),triglyceride(TG)and free fatty acid(FFA)were decreased significantly in H-KGM group(p<0.01).Pathological observation of liver tissue section showed that liver injury decreased after KGM intervention.RT-qPCR results showed that KGM down-regulated the genes expression of LXR?,HMGCR,PPAR?,FAS,ACC1,CHREBP,SREBP-1C in liver tissue,inhibited the synthesis of fatty acids in liver,affected the lipid metabolism of liver and reduced the accumulation of TG in liver tissue.It can improve liver lipid metabolism disorder and maintain lipid metabolism and cholesterol homeostasis.Besides,KGM down-regulated the expression of IL-6,TNF-? and MCP-1,so decreased inflammation and insulin resistance in liver.The results of high throughput sequencing and gas chromatographic analysis showed that KGM could increase the diversity of gut microbiota,decrease the abundance of bacteria that promote obesity and inflammation,increase the abundance of healthy bacteria,and increase the concentrations of acetic acid,propionic acid and butyric acid.And the results showed that H-KGM has a better effect on metabolic disorder induced by high fat diet.