Effect And Mechanism Of Methylene Blue On Liver Injury In Rats With Different Stages Of Sepsis

Objective: To explore the effect of Methylene blue(MB)on liver injury in sepsis rats at different stages and its possible mechanism,so as to provide new ideas for clinical prevention and treatment of sepsis.Methods: 126 female Wistar rats by cecal ligation and puncture(CLP)model of sepsis rats,which were randomly divided into 0,6,12,18,24,30,36 h group,each time point was again subdivided into sham operation group(S group),sepsis group(group C)and methylene blue group(M group).In methylene blue group,15 mg/kgmethylene blue was injected into a caudal vein at 0,6,12,18,24,30,36 hours after CLP in the rats in correspondingsubgroups,respectively;in the sepsis and sham operation subgroups,the same amount of 0.9%normal saline was given.After administration for 6hours in various groups,theblood samples were collected and the rats were killed and the liver tissue was collected promptly.Automatic biochemical detection of serum aspartate aminotransferase(AST),alanine aminotransferase(ALT),total bilirubin(TBIL)level,the expression ofinducible nitric oxide synthase(iNOS)m RNA of liver tissues was determined by the real-time fluorescent quantitative reverse transcription-polymerase chain reaction(qRT-PCR),and the protein expression of i NOS was etermined by Western Blot,the liver tissue was stained with HE to observe the pathological changes.Results: Compared with group S,the serum AST level of C group increased significantly at 6~36h time points,all P<0.01,The serum AST level of M group increased significantly at 6~36h time points,and 6h<0.05,12~36h time points,all P<0.01;C group and M group rats serum ALT level in 12~36h at each time point were significantly increased,P<0.01;C group and M group rats serum TBIL level in 6~36h at each time point were significantly increased,P<0.01;C group of liver tissue iNOS mRNA expression was significantly increased in 0 and 6,12,18 h time points,P<0.01,after the 24 h point the expression of i NOS mRNA had no significant change;The expression of iNOS protein in the liver tissue of C group increased significantly at 6,12,18,and 36 h time points,all P<0.01.Compared with group C,serum AST level in group M was significantly lower at 24 h,P<0.05,serum ALT level decreased significantly in 18~36h,18 h,24h,36 h time points P<0.05,and 24 h P<0.01;The serum level of ALT decreased significantly in the 18~36h points,in 18 h,36h points,P<0.05,24h<0.01 P;The expression of iNOS mRNA in liver tissue decreased significantly in 0,12,18 h points,P<0.05;The expression of iNOS protein in liver tissue were decreased in 6,12,18,36 h points,all P<0.05.Liver histopathological section showed that C group and M group began to develop liver injury at 6h time point,and the degree of injury increased with time.However,the degree of pathological damage in M group was lighter than that in C group.Conclusion: Methylene blue can reduce the levels of AST,ALT and TBIL in the middle and late stage of sepsis,significantly inhibit the expression of iNOS in the liver of sepsis,reduce the degree of liver injury in the middle and late stage of sepsis,and have a protective effect on liver injury in septic rats.