Anti-obesity Effect And Mechanism Of Galactooligosaccharides

At present,the incidence of overweight and obesity has increased dramatically worldwide.The harm caused by obesity can no longer be ignored.However,there are fewer types of diet pills on the market and there are large side effects.Therefore,it is urgently needed that search safe,effective and non-toxic anti-obesity drugs.Galactooligosaccharides(GOS)is a natural prebiotic that can be used by intestinal microbes.As a prebiotic,GOS has a wide range of recognition,good therapeutic effects and high safety.In this study,we established the obese SD rat model by high fat diet induction,studied the weight loss activity of GOS in vivo,screened out the pathways through gene differential spectrum,and carried out fluorescence quantitative polymerase chain reaction(RT-PCR)and protein immunoblotting(WB)experiments to preliminarily explore its mechanism.Results of weight loss activity:(1)The GOS dose group can significantly reduce the weight gain of obese SD rats induced by high-fat diet without affecting the appetite of SD rats,and can significantly reduce the total fat pad and fat body ratio in rats,indicates that GOS has a good weight-loss effect;(2)It was found in the blood lipid level study that each dose group of GOS can improve the serum TC,TG,LDL-C and HDL-induced in high fat diet-induced obese SD rats,indicates that GOS can improve the lipid metabolism in serum;(3)In the detection of liver function index,GOS each group significantly improved the serum AST and ALT levels in obese SD rats induced by high-fat diet,indicates that GOS also has a certain liver-protecting effect;each dose group of GOS significantly improved the serum Glu concentration in obese SD rats induced by high-fat diet,indicating that it has hypoglycemic activity,and high dose of GOS can also improve glucose tolerance in SD rats;(4)Next,the effects of GOS on liver tissue and lipid metabolism were investigated.It was found that GOS dose groups significantly reduced liver weight;GOS significantly improve TC,TG,LDL-C and HDL-C in liver;from the overall morphology,color and tissue section of liver tissue,the GOS dose group can alleviate and improve the phenomenon of lipid accumulation;the above results show that GOS can improve the level of lipid metabolism in the liver,at the same time,adipose tissue sections showed that GOS can inhibit the expansion and growth of epididymis,subcutaneous and perirenal adipose tissue cells in vivo compared with the Model group.The gene difference spectrum results show:In the liver,GOS up-regulated 300 genes and down-regulated genes 266 compared with Model;differential gene KEGG functional analysis showed that differential genes were mainly distributed in ether lipid metabolism,lipid metabolism,MAPK signaling pathway,bile secretion,tyrosine metabolic pathways.In the adipose tissue group,GOS up-regulated genes 120 and down-regulated genes 428 compared with Model;differential gene KEGG functional analysis showed that differential genes were mainly distributed in heat production,MAPK signaling pathway,PPAR signaling pathway,cholesterol metabolism,PI3K/ AKT signaling pathway,fatty acid metabolism,arachidonic acid metabolism and other pathways.Through the analysis of the gene differential spectrum,the related genes and protein of white fat browning and lipid metabolism pathway in the liver were selected for subsequent experiments.Anti-obesity mechanism research results:In epididymal fat,GOS can increase the protein expression levels of UCP1,PPAR?,PGC1?,PRMD16 and ATF2 in all dose groups;all of them can increase the gene expression levels of UCP1,PPAR?,PGC1?,PRMD16,ATF2,p38 MAPK and PKA,indicating that GOS can promote fat browning of epididymis in obese SD rats induced by high fat diet.In brown fat,all doses of GOS increased the protein expression levels of UCP1,PPAR?,PGC1?,PRMD16,and increased the expression of UCP1 gene,indicating that GOS can promote brown fat formation and further increase the body's heat production.In white fat and liver,GOS can promote the protein expression of CYP7A1,LDLR,LXR?,PPAR? and decrease the protein expression of SREBP2,indicating that GOS regulates the body's lipid metabolism by promoting cholesterol catabolism.