Effects Of Helicobacter Hepaticus Infection On Carbon Tetrachloride-induced Liver Injury In BALB/c Mice

Background Liver injury is a common clinical liver disease,mainly manifested as acute liver injury and chronic liver injury.Carbon tetrachloride（CCl4）is a common chemical substance that can induce liver injury,acute liver injury can lead to liver failure,persistent mild liver injury can lead to fibrosis and cirrhosis,results in serious threat to human health.Helicobacter hepaticus（H.h）is a gram-negative bacterium mainly colonized in the intestinal tract of host,belong to campylobacter helicobacter family helicobacter genus.Studies have shown that environmental stress such as high-fat feeding can promote the transfer of H.h from intestinal tract to liver in hosts.However,the role of H.h infection in chronic liver fibrosis and acute liver injury remains unclear.BALB/c mice were used as animal models in this study,treated with a combination of H.h infection and CCl4,to investigate the influence of H.h infection on the course of acute and chronic liver injury induced by CCl4.Purpose and Method（1）To investigate the effects of H.h infection on chronic liver injury in BALB/c mice induced by CCl4.In this study,40 male BALB/c mice（5-6 weeks of age）were randomly divided into 4 groups（Control group,H.h group,CCl4 group,H.h+CCl4 group）.The control group was fed normally.H.h group was given H.h intragastric treatment once every 3 days for 2 weeks.CCl4 group was treated with intraperitoneal injection of 40%CCl4 solution once every 3 days.In the H.h+CC14 group,40%CCl4 solution was intraperitoneal injection every 3 days 1 week after the end of H.h intragastric administration.Samples were taken at 4 weeks and 12 weeks after CCl4 injection.Serum alanine aminotransferase（ALT）and aspartate aminotransferase（AST）contents were detected.Liver fibrosis was observed by hematoxylin-eosin staining（HE）and Sirius red staining,The expressions of IL-6,IL-33 α-SMA,TNF-α and TGF-β in mouse liver were detected by immunohistochemistry and fluorescence quantification（RT-qPCR）.（2）To investigate the effects of H.h infection on CCl4 induced acute liver injury in BALB/c mice.In this study,40 male BALB/c mice（5-6 weeks of age）were randomly divided into 4 groups（Control group,H.h group,CCl4 group,H.h+CCl4 group）.The control group was fed normally.H.h group was given H.h intragastric treatment once every 3 days for 2 weeks.CCl4 group was treated with 40%CCl4 solution intraperitoneal injection once.The patients in the H.h+CCl4 group were intraperitoneal injection with 40%CCl4 solution 8 weeks after the end of H.h intragastric administration.Samples were taken at 2 d,5 d,9 d and 12 d after CCl4 injection,the detection indexes were the same as those in chronic experiment.Results（1）Chronic experimental results showed,after 4 weeks of treatment,mild liver fibrosis was observed in both CCl4 group and H.h+CCl4 group,while no obvious lesions were observed in other groups.After 12 weeks of treatment,the amount of H.h colonization in liver of mice in the H.h+CCl4 group was significantly increased compared with that in the H.h+CC14 group,the levels of ALT and AST in serum of mice in the H.h+CC14 group were significantly increased compared with that in the CC14 group,the amount of collagen fiber deposition in liver was increased,and the transcription levels of inflammatory and fibrosis related factors were significantly increased.（2）Acute experimental results showed,at 2 d,5 d and 12 d,there was no significant difference in all kinds of data of CCl4 group and H.h+CCl4 group.At 9 d,compared with CCl4 group,Serum alanine aminotransferase（ALT）and aspartate aminotransferase（AST）contents were increased in H.h+CCl4 group.Severe acute liver injury was observed by hematoxylin-eosin staining（HE）,sirius red staining.The expression levels of IL-33 antibody and α-SMA protein were detected by immunohistochemistry and Western blot,the transcription levels of IL-6,TNF-α,TGF-β,iNOS and IL-4 were detected by fluorescence quantitative PCR.Conclusion In summary,CCl4 treatment can promote H.h colonization in mouse liver,and H.h infection can aggravate CCl4-induced liver fibrosis and inhibit the repair of acute liver injury.This study can provide theoretical basis for further revealing the pathogenesis of liver injury disease.