Effect And Mechanism Of Cordyceps Militaris On Amelioration Of Type Ⅱ Diabetes Mellitus With Nonalcoholic Fatty Liver Disease Based On "Gut Liver Axis"

Type 2 diabetes mellitus(T2DM)and non-alcoholic fatty liver disease(NAFLD)are both metabolic diseases.Complex association exists between NAFLD and T2DM and they are known to frequently coexist and act synergistically to increase the risk of adverse clinical outcomes.The gut liver axis refers to the communication between the intestine and the liver,which is mainly mediated by the metabolites produced by the hepatic portal vein circulation,and plays an important role in the development of NAFLD,Bile acids are synthesized in the liver and participate in the enterohepatic circulation to promote the digestion and absorption of lipids,which has been proved to be a regulator of T2DM.Cordyceps militaris,as a medicinal and edible fungus,contains a variety of active substances,such as cordycepin,cordyceps polysaccharide,mannitol,adenosine and so on that has been proved to have pharmacological effects such as antioxidant,antitumor,anti-inflammatory reaction,enhancing immunity and relieving metabolic diseases such as T2DM,obesity and NAFLD.Based on the confirmation that C.militaris can regulate the intestinal flora and its metabolites in T2DM mice,the C.militaris water extract and cordycepin were taken as the research objects,and the intervention mechanism of C.militaris on T2DM with NAFLD were explored from the perspective of"intestinal flora-bile acid metabolism".We expect to provide new research ideas for the physiological activity mechanism of C.militaris and provide data support for the study of the metabolic interaction between C.militaris and specific bacteria or bile acids.1.Cordycepin and C.militaris water extract reduce the hyperglycemia level of T2DM mice,regulate intestinal flora and enhance the intestinal barrier.T2DM mice were established by feeding high sucrose and high fat feed and injecting streptozotocin,and were given different doses of cordycepin and C.militaris water extract.The results showed that the intervention of C.militaris significantly reduced fasting blood glucose,TNF-α,IL-6 in T2DM,and alleviated the inflammatory cell infiltration of colon and vacuolization of liver cells in T2DM;Compared with the T2DM group,C.militaris decreased the relative abundance of Lachnoclostridium,increased the relative abundance of beneficial bacteria such as Dubosiella,Akkermansia,Roseburia,etc;In addition,cordycepin upregulated the mRNA expression level of tight junction proteins in T2DM,which verified the beneficial effect of cordycepin on enhancing intestinal barrier.2.C.militaris improved the liver injury of mice,it may improve the inflammatory response of T2DM with NAFLD by regulating TLR4/NF-κB pathway,which was an important role in inflammatory signaling.T2DM&NAFLD model was established with high fructose-high fat diet,and treated with cordycepin and C.militaris water extract at the same time.The results showed that compared with the model group,the levels of fasting blood glucose,fasting insulin and HOMA-IR in the cordycepin group and C.militaris water extract group were significantly reduced,C.militaris could improve insulin resistance.C.militaris also reduced the levels of ALT,GLP-1 and alleviated liver injury;C.militaris improve the inflammatory reaction and oxidative stress in T2DM&NAFLD mice by intervening TLR4/NF-κB pathway.Compared with the model group,the serum levels of inflammatory factors and the mRNA expression levels of TLR4,NF-κB in the cordycepin group and C.militaris water extract group were decreased,which was confirmed that C.militaris played a role in alleviating the inflammatory reaction in T2DM and NAFLD.3.Intestinal flora and bile acid metabolism play an important role in the course of metabolic diseases.The ameliorative effect of C.militaris on T2DM&NAFLD depends on its regulation of intestinal flora;Dehydrocholic acid may be a potential therapeutic target for C.militaris to improve liver diseases.A total of 4788 metabolites were detected in the liver samples,compared with the control group,the cordycepin group significantly increased the level of dehydrocholic acid in liver,and it has a strong positive correlation with the potential beneficial bacteria Blautia,which was verified in fecal bile acid metabolomics.The results of fecal samples showed that C.militaris significantly increased the relative abundance of beneficial bacteria such as Oscillibacter,Roseburia and Lactobacillus.Some bile acids,such as deoxycholic acid,taurocholic acid,taurocholic acid chenodeoxycholic acid,that promote the development of liver diseases are down-regulated,and some bile acids such as hycholic acid,ursocholic acid,dehydrocholic acid and cholic acid-7-sulfate,that improve metabolic diseases are up-regulated,there was a correlation between the relative abundance of some intestinal flora and bile acid levels,cholic acid-7-sulfate may be an important regulatory factor for cordycepin to improve disease.In conclusion,we found that the intervention of cordycepin and C.militaris water extract can significantly regulate the intestinal flora of T2DM,strengthen the intestinal barrier,which has the potential role of alleviating the development of T2DM;C.militaris regulate the expression of TLR4/NF-κB signaling pathway to reduce inflammatory response and improve the disease.C.militaris improve the development of T2DM&NAFLD by interfering with the"gut-liver axis",increasing the relative abundance of beneficial bacteria such as Roseburia and Blautia,and increasing the level of beneficial bile acids such as cholic acid-7-sulfate,dehydrocholic acid,ursocholic acid.