Protective Effect And Mechanism Of Cornel Iridoid Glycoside On Alcoholic Liver Injury In Mice

Objective:To study the protective effect of iridoid glycosides from Cornus officinalis on alcoholic liver injury mice,and to explore the effect mechanism of iridoid glycosides on alcoholic liver injury mice from the perspective of liver oxidative stress,inflammatory response and intestinal function.To provide a theoretical basis for the treatment of alcoholic liver injury with iridoid glycosides from Cornus officinalis.Methods:C57BL/6 mice were intragastric with alcohol to establish alcoholic liver injury model.Mice were randomly divided into 6 groups according to body weight,with 10 mice in each group.Control group(NC group):distilled water gavage;Model group(AL group):mice were gavaged with 30%ethanol,1 h later,the same volume of distilled water was gavaged;Positive drug group(PC group):mice were gavaged with 30%ethanol,1 h later,100 mg/kg silybin was gavaged;Iridoid glycosides of Cornus officinalis in low-dose,medium-dose and high-dose groups(CIG50,100 and 200 groups):mice were gavaged with 30%ethanol,and after 1 h,mice were gavaged with 50 mg/kg,100 mg/kg and 200 mg/kg iridoid glycosides of Cornus officinalis,respectively.The model was made and the drug was administered for 15 days.On the 16 th day,50%ethanol was given intragastrically,and the drug was given 1 h later.1.Whether the establishment of the model was successful was evaluated by detecting serum ALT and AST levels.2.The histopathological changes of liver in each group were observed by liver H&E staining.3.The levels of LPS,SOD,MDA,CAT,GSH and biochemical indexes of inflammatory factors such as TNF-α,IL-1β and IL-6 were used.4.The expressions of TLR2,TLR4 and NF-κB genes in liver were detected by qPCR.5.Intestinal H&E staining and immunohistochemical staining were used to detect the expression of ZO-1 and occludin,and to evaluate the intestinal barrier function.6.The intestinal flora of mice was analyzed by 16S rDNA sequencing.7.The contents of seven kinds of short-chain fatty acids(acetic acid,propionic acid,2-methyl-butyric acid,butyric acid,isobutyric acid,valeric acid and isovaleric acid)in intestinal tract of mice were detected by GC-MS.Results:1.CIG intervention could reduce the levels of ALT,AST and endotoxin LPS in serum of the model mice with alcoholic liver injury.Compared with the model group,dose groups of Cornel iridoid glycoside could improve the pathological changes of liver cells to a certain extent and reduce the infiltration of inflammatory cells.2.CIG can improve the levels of MDA,CAT and GSH in liver,enhance the ability of anti-oxidative stress in liver,and delay the inflammatory process of mice by reducing the expression of inflammatory cytokines TNF-α,IL-1β and IL-6 in liver.3.CIG can reduce the expression of TLR4 and NF-κB genes,suggesting that CIG may have protective effect on liver injury caused by alcohol through regulating TLR4/NF-κB signaling pathway.4.Colon pathological observation showed that CIG alleviated intestinal damage in alcoholic liver injury model mice,and increased the expression of ZO-1 and Occludin in the intestinal tract,suggesting that CIG may improve intestinal barrier function by affecting the expression of ZO-1 and Occludin.5.CIG improved the diversity of intestinal flora,changed the composition and abundance of the community,reduced the decline of Firmicutes/Bacteroidetes ratio caused by alcohol,reduced the increase of pathogenic bacteria in the intestinal tract of mice caused by alcohol,increased the content of Lactobacillus,and maintained the balance of intestinal microbes.6.CIG increases the contents of acetic acid,propionic acid,2-methyl-butyric acid,butyric acid,isobutyric acid and valeric acid in the intestine.Therefore,CIG may improve intestinal barrier function or reduce liver inflammation by affecting intestinal short-chain fatty acids,thus playing a protective role in the intestine and liver.Conclusion:1.Iridoid glycosides from Cornus officinalis have protective effects on alcoholic liver injury in mice.2.The effect of iridoid glycosides from Cornus officinalis on alcoholic liver injury was dose-related,and the effect of high-dose group was the best.3.Iridoid glycosides from Cornus officinalis can improve the antioxidant ability of liver,reduce the oxidative stress response of liver,and reduce the inflammatory response.The mechanism of action may be related to correcting the disturbance of intestinal flora,improving intestinal barrier function and improving intestinal environment.