Changes Of TLR4/JNK Signaling Pathway And Effects Of Different Drugs On Myocardial Injury In Mice

ObjectiveThrough the analysis of myocardial injury in mice with sepsis and the changes of TLR4/JNK signaling pathway after simvastatin and esselor,the effects of drugs on myocardial injury protection and the molecular mechanism were further discussed.It provides a theoretical basis for the development of such drugs in clinic.The first part:Mice with sepsis myocardial injury were divided into three groups: model group,normal group and sham-operated group.LPS was injected intraperitoneally in model group,without any treatment in normal group,and normal saline was injected into sham-operated group.Ten mice in each group were taken to record their general state and survival,and another 10 were taken into myocardial tissue respectively.Serum cTnI was detected by HE staining and ELISA.(1)24 hours after modeling,LPS-treated mice showed abnormal behavior.Behavior: activity decreased significantly and action was slow;life status: hair erected loosely,eyelids had viscous secretions,shivering;mental aspect: depression,weakened response to external stimuli.The mice in the normal group and sham-operated group did not show these characteristics.Survival analysis of three groups of mice for a week showed that there was no death in normal group and sham-operated group,while 4 mice in model group died,the survival rate was 60%.(2)HE staining results of myocardial tissue are shown in Figure 2.1.Compared with normal group and sham-operated group,LPS-induced sepsis myocardial injury model group has irregular arrangement of myocardial fibers;some areas are fractured and deformed,and the cytoplasm is homogenized;some cross striations are blurred or even disappeared,and the chromatin is loose;blood vessels are visible.Hemorrhage,inflammatory cell infiltration.(3)Compared with normal group and sham-operated group,the results showed that the serum levels of C TnI in septic myocardial injury mice induced by LPS were significantly increased(P < 0.05).There was no significant difference in C TnI level between sham-operated group and normal group(P > 0.05).The second part:The mice were divided into four groups: model group,sham operation group,esmolol group,simvastatin group,esmolol group and simvastatin group.On the basis of model group,esmolol group and simvastatin group were given esmolol and simvastatin for 24 hours at a dose of 15 mg/kg,serum cTnI and TNF-a were detected by ELISA,TLR4 in myocardium was detected by Western blot.The expression of JNK,p-JNK,c-jun and p-c-jun.(1)The mice in the model group had mental retardation,slow action and disordered hair.The mice in the esmolol group and simvastatin group all had the above symptoms,but the situation was better than that in the model group.The sham operation group had no such symptoms.(2)ELISA test found that compared with the sham-operated group,the serum cTnI in the model group was significantly higher,indicating that myocardial injury occurred.The cTnI content in the esmolol group and simvastatin group was lower than that in the model group(P < 0.05),higher than that in the sham-operated group,indicating that the two drugs had a certain protective effect on myocardial injury,compared with the sham-operated group,esmolol group and simvastatin group.Lol cTnI content was lower than that of simvastatin group(P < 0.05).(3)The expression of TNF-alpha in serum of model group was significantly higher than that of sham-operated group,while the levels of TNF-alpha in Slool group and simvastatin group were significantly lower than those of model group(P < 0.05),with significant difference(P < 0.05).(4)Western blot results showed that p-JNK/JNK and p-c-jun/c-jun indicated the relative expression of phosphorylation index.Western blot results showed that TLR4,JNK and p-JNK in the model group were significantly higher than those in the sham-operated group(P < 0.05),while c-jun and p-c-jun were slightly higher than those in the sham-operated group,but there was no statistical difference.The indexes of TLR4,JNK,p-JNK and c-jun in the two groups were decreased in varying degrees(P < 0.05),but there was no significant difference in p-c-jun.The third part:Mice cardiomyocyte HL-1 was divided into four groups: control group,LPS group,esmolol group and simvastatin group.LPS group cells were treated with LPS for 24 hours.Esmolol group and simvastatin group cells were treated with LPS and then treated with LPS for 2 hours.ELISA and Western blot were used to detect the above.The results showed that the expression of cTnI,TNF-alpha,TLR4,JNK and p-JNK in LPS group was higher than that in control group(P < 0.05),while esmolol and simvastatin could inhibit the high expression of cTnI,TNF-alpha,TLR4,JNK and p-JNK.(1)Compared with the control group,the levels of cTnI and TNF-a in LPS group were significantly higher(P < 0.05),while the levels of cTnI and TNF-a in simvastatin group and esmolol group were significantly lower than those in LPS group(P < 0.05).(2)Western blot results showed that TLR4,JNK and p-JNK in LPS group were significantly higher than those in control group(P < 0.05),while c-jun and p-c-jun had no significant changes(P > 0.05);TLR4,JNK and p-JNK in simvastatin group and esmolol group were significantly lower than those in LPS group(P < 0.05).Conclusion:LPS activates TLR4,TLR4 promotes JNK phosphorylation and JNK pathway in sepsis-induced myocardial injury.Esmolol and simvastatin can inhibit the expression of TLR4 and JNK in different degrees.