The Protective Effect Of Coprococcus Catus On Hepatic Ischemia-Reperfusion Injury In Mice

Backgrounds and ObjectivesIschemia-reperfusion injury(IRI)means that the organs or tissues of the body are affected by ischemia and hypoxia,and after the blood supply is restored,the original functions of the organs and tissues of the body cannot be restored,besides the degree of damage is aggravated.IRI can occur in various organs of the body,of which Hepatic ischemia-reperfusion injury(HIRI)is the most common,which is an important complication after body shock or liver surgery.In addition,HIRI is also one of the important factors affecting the success rate of liver surgery and postoperative survival rate of patients.Although the understanding of HIRI has deepened with the development of medical technology,but so far there is no specific method to improve the damage to organs and tissues caused by ischemia-reperfusion.The gut microbiota is closely related to the occurrence of many diseases,and the disturbance of the gut microbiota can easily lead to the occurrence of various diseases.It has been reported before that some gut microbiota can improve liver injury through themselves or their metabolites.Therefore,in order to further explore the direct connection between hepatic ischemia-reperfusion injury and intestinal flora,we studied the specific intestinal symbiotic bacteria--Coprococcus catus,C.catus which makes potential contribution to HIRI.MethodsExperiment 1:The eight to ten weeks old C57BL/6 mice were randomly divided into 4 groups:control group(IR,rep 6 h),broad-spectrum(ABX)intervention group IR+ABX,rep 6 h),clearing gram-positive bacteria group(IR+Gla(+),rep 6 h),clearing gram-negative bacteria group(IR+Gla(-),rep 6 h).After 4 days of different antibiotic interventions,mice were subjected to hepatic ischemia-reperfusion surgery,and then the left lobe,middle lobe and serum samples of the mouse liver were collected for subsequent analysis.Experiment 2:The eight to ten-weeks old C57BL/6 mice were randomly divided into 3 groups:(1)HIRI model group(IR,rep 6 h);(2)The activated C.catus group was given activated C.catus rearing(IR+C.catus,rep 6 h);(3)The inactivated C.catus group was given inactivated C.catus rearing(IR+dead C.catus,rep 6 h).The activated C.catus group and the inactivated C.catus group were gavaged with activated and inactivated C.catus once a day respectively,and the blank group was gavaged with the same amount of DPBS for 3 days.The mice were subjected to liver ischemia-reperfusion and the left lobe,middle lobe and serum samples of mice were collected for subsequent analysis.Experiment 3:The eight-week-old C57BL/6 mice were randomly divided into C.catus culture supernatant pretreatment group(IR+culture supernatant,rep 6 h)and blank medium treatment group(IR+blank,rep 6 h).After 3 days of treatment,mice were treated with liver ischemia-reperfusion surgery,and liver and serum samples were collected for subsequent analysis.Experiment 4:The eight-week-old C57BL/6 mice were randomly divided into control group(IR,rep 6 h),macrophage removal group(IR+Clodronate liposomes,rep 6 h)and macrophage removal combined with inactivation of C.catus group(IR+Clodronate liposomes+dead C.catus,rep 6 h).After corresponding pretreatment,macrophage removal group and macrophage removal combined with inactivated C.catus group were given Clodronate liposomes to remove macrophages before hepatic ischemia-reperfusion surgery 24 h.ResultsResults 1:The levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST)and myeloperoxidase(MPO)activity in the Gla(+)group and ABX group were significantly higher than the control group and the Gla(-)group.In addition,the results of liver pathology showed that the liver injury of the mice in the Gla(+)group and the ABX group was significantly aggravated,meanwhile representative cytokines and chemokines of HIRI in Gla(+)group and ABX group were significantly up-regulated compared with Gla(-)group and control group.Result 2:Compared with the HIRI model group,the levels of ALT,AST and MPO activity of the mice in the C.catus treatment group were significantly reduced.And the liver pathological damage of the mice in the C.catus treatment group was also significantly improved.In addition,the positive staining of Ly6G in the two groups of mice was also significantly reduced compared to the HIRI model group.At the level of gene,liver inflammatory factors and chemokines were down-regulated to a certain extent in C.catus treatment group.Result 3:There were no significant differences in the levels of ALT,AST,MPO activity and liver pathology results of the C.catus culture supernatant pretreatment group compared with the blank medium treatment group.Result 4:The levels of ALT,AST,MPO activity and liver pathological damage in the macrophage removal group and the macrophage removal combined with inactivated C.catus group were lower than those in the model group.At the level of gene,the expression levels of cytokines and chemokines were also down-regulated to a certain extent.ConclusionsThe data show that elimination of Gram-positive bacteria aggravates the level of hepatic ischemia-reperfusion injury,whereas it doesn’t happen in elimination of Gram-negative bacteria.The liver injury was significantly improved in HIRI mice which treated with intestinal Gram-positive commensal bacteria C.catus,besides the protection effect of inactivated C.catus is more obviously.In addition,after the removal of macrophages,the protective effect of C.catus decreased to a certain extent on HIRI,but there was still a protective trend.