Gut Microbiota Mediates The Antilipemic Effect Of Bupleuri Radix Through FGF21 Energy Metabolism Pathway

Bupleuri Radix,a Chinese herbal medicines listed in the Chinese Pharmacopoeia,has been commonly used in clinical.It has a wide range of biological activities,include regulating metabolic disorders,antipyretic etc.Nowadays,our society faces an important scientific proposition on how to safely and effectively improve metabolic syndrome.Among them,gut microbiota is closely related to metabolic diseases,and there is an interaction relationship with Chinese herbal medicines.It is not yet mature on the pharmacodynamic effects of intestinal bacteria on traditional Chinese medicine.On the other hand,the metabolic hormone Fibroblast Growth Factor 21(FGF21)is a promising therapeutic target for nonalcoholic fatty liver,and a new drug for the treatment of liver disease has been successfully developed clinically.The research basis of our research group indicates that Bupleuri Radix extract can regulate FGF21 gene.It needs the further research on whether Bupleuri Radix can improve lipid metabolism through FGF21 and its metabolic pathway.The role of gut microbiota and metabolic factor FGF21 in ameliorate lipid metabolism related to the Chinese medicine Bupleuri Radix has not been studied in depth.The main direction of this paper is based on this perspective.Objectives(1)Study on the effect of Bupleuri Radix on metabolic factor FGF21 and its metabolic pathway in mice fed with HFD.(2)Study on the regulation of Bupleuri Radix on the gut microbiota of HFD-fed mice.(3)To study the regulation of Bupleuri Radix on lipid metabolism disorder in obese mice induced by HFD.(4)Quantify the gut bacteria strains that changed by Bupleuri Radix;Study these gut bacteria potential effects on the lipid metabolism of Bupleuri Radix.(5)To investigate the effect of gut bacteria colonization on lipid metabolism and energy metabolism of FGF21 in HFD-fed mice.(6)Analyze the effect of intestinal bacteria on the chemical constituents of Bupleuri Radix extract.Methods(1)To establish a HFD-induced obese mouse model;to confirmed the expression of FGF21 protein in liver tissue by Western Blot;to study the effect of Bupleuri Radix on the Overall FGF21 and its metabolic pathway in HFD mice.(2)To study the effect of Bupleuri Radix on the intestinal microflora structure and abundance of mice fed with HFD by pyrosequencing.(3)Analyze the effects of Bupleuri Radix on physiological and biochemical factors and major metabolic regulation genes in vivo.(4)Construction of recombinant plasmid standards for microbial strain-specific DNA fragments;quantitative analysis of the role of Bupleuri Radix on specific microbial strains based on qPCR.(5)The intestinal microbial anaerobic culture technique was used to study the role of intestinal bacteria changed by Bupleuri Radix in the lipid-lowering effect in vivo.(6)The main chemical constituents of Bupleuri Radix were analyzed by LC-Q-TOF/MS;and the metabolism of intestinal bacteria on the active ingredients of Bupleuri Radix was analyzed.Results(1)Bupleuri Radix can promote the secretion of FGF21 metabolic factor in liver;it can up-regulates the expression of co-receptor factor KLB,the downstream effector proteins GLUT1 and PGC-1α.The lipid-lowering effect of Bupleuri Radix was mainly in the liver;and it regulated systemic lipid metabolism by acting on the liver FGF21 metabolic pathway.(2)Bupleuri Radix can regulate the structure and abundance level of gut microbiota in HFD-fed mice.The PICRUSTs data processing tool predicted that the changes in the structure of intestinal microbial bacteria can improve metabolic disorders such as short-chain fatty acids induced by HFD.(3)Bupleuri Radix can regulate the lipid metabolism on HFD-fed mice,and its lipid-lowering effect is mainly related to fatty acid metabolism.(4)The 16s gene sequencing data has been deeply excavated.It is found that the abundance of three strains changed significantly after Bupleuri Radix treatment,namely:Bacteroides acidifaciens was increased,Clostridium cocleatum and Ruminococcus gnavus were decreased.(5)By feeding high-fat diet mice with intestinal bacteria,it was found that the physiological effects of Bacteroides acidifaciens were consistent with the HFD mice under the treatment of Bupleuri Radix.Ruminococcus gnavus has a negative effect on the lipid metabolism,which is the same as the pathophysiology state of mice caused by high-fat diet.(6)The analysis in vitro showed that the main chemical component of Bupleuri Radix were mainly saikosaponins.The intestinal microbes had metabolic transformation effects on these constituents.The prototype components were not detected in blood.ConclusionBupleuri Radix had a lipid-lowering effect on HFD-fed mice,and it improved the body’s fatty acid metabolism mainly through regulating the FGF21 metabolic pathway.Currently,this paper has confirmed that the lipid-lowering effect of Bupleuri Radix is related to the change of intestinal microbial bacteria distribution.But,whether the metabolic transformation of gut microbiota on the chemical components of Bupleuri Radix are involved in the above process,still needs the further research.