Protective Effect And Mechanism Of Methylprednisolone Combined With Esmolol On Sepsis Induced Acute Lung Injury

Objective: To observe the protective effect and mechanism of esmolol and methylprednisolone on sepsis induced acute lung injury;To observe whether the combined use of drugs has better protective effect on acute lung injury,and whether there are different effects of intervention at different time points.And to explore the mechanism of sepsis-induced acute lung injury and its protective effect by esrolol and methylprednisolone.Methods: Male Kunming mice were randomly divided into five groups Blankcontrol group(BL): There are 5 mice.The control group only receied an injection of same amount of saline as lipopolysaccharide(LPS);Sepsis group(SE): There are 15 mice.LPS(10 mg / kg)was injected intraperitoneally to establish the model of sepsis acute lung injury;Esmolol group(ES): There are 15 mice.Esmolol(20mg / kg)wasinjected into abdominal cavity slowlyafter the model establish;Methylprednisolone group(ME): There are 5 mice.Methylprednisolone(5mg / kg)was injected intraperitoneallyslowly;Combined group(CO):There are 5 mice.Esmolol and Methylprednisolonewere combined interventionby peritoneal injection after the model establish.Each group was divided into three subgroups according to the different time points of intervention: 0h,6h and 12 h,and there were 6 mice in eachsubgroup.Taken 24 hours after modeling by observing and detecting the levels of IL-6 and TNF-? in peripheral blood by ELISA,evaluating the degree of lung injury by HE staining and the degree of pulmonary edema by the wet/dry ratio of lung tissue.After taking the BALF,The protein concentration in BALF was measured by BCA method,and the number of inflammatory cells in BALF was counted under microscope;Preparation of lung tissue homogenate,detect the content of MPO and MDA respectively according to the operation method of MPO and MDA kit,and the relative expression of p65 and I?B-? in lung homogenate was detected by Western blotting.RT-PCR was used to detect the relative expression of IL-6 and TNF-? m RNA in lung homogenate.Results: 1.After the model of acute lung injury in sepsis mice was successful established,the mice in the SE group showed the symptoms of decreased activity,increased body temperature,shortness of breath,and general shivering.The mice in the ES group and the me group showed less symptoms than those in the SE group,while the mice in the CO group were more active.With the delay of the intervention time point,the general situation of the mice gradually became worse.2.Comparison of W/D value among groups: in the same intervention group(ES group,me group and co group),W/D value gradually increased with the delay of intervention time point(P< 0.05);in the same time point,W/D value of each intervention group was higher than BL group and lower than SE group(P< 0.05);in the same time point,W/D value of CO group was lower than ES group and ME group(P< 0.05).3.MPO activity comparison: the three intervention groups had the same change trend at different time points,the highest MPO activity at 12 h,the lowest MPO activity at 0h(P< 0.05);between different groups at the same time point,the MPO activity of the three intervention groups was higher than that of BL group,significantly lower than that of SE group(P< 0.05),and the MPO activity of ES group and ME group was higher than that of CO group(P< 0.05),and there was no difference between ES group and ME group Statistical difference(P> 0.05).4.MDA value comparison: in the intervention group,the MDA value was different at different time points,which was characterized by the earlier the intervention time,the smaller the MDA value,otherwise it gradually increased(P< 0.05);the comparison between the two groups at the same time point showed that the MDA value of ES group and ME group was lower than that of CO group,and the MDA value of each experimental group(SE group,ES group,ME group,CO group)was higher than that of the blank group(BL group),The MDA value of the intervention group(ES group,ME group,CO group)was significantly lower than that of the sepsis group(P< 0.05).5.Comparison of protein content in BALF: the earlier the intervention time point,the lower the BALF protein content in each intervention group,otherwise,the higher the BALF protein content(P < 0.05);At the same time of intervention time,it was found that the BALF protein content of BL group was the lowest and that of SE group was the highest.ES group and ME group could significantly reduce the protein content of BALF,and the protein content of BALF in CO group was further reduced compared with ES group and ME group(P< 0.05).6.The number of inflammatory cells in BALF: The number of inflammatory cells in ES group,ME group and CO group was different at different intervention time points,the main performance was that the later the intervention time point,the more inflammatory cells infiltration in the alveoli,on the contrary,the less(P < 0.05);Compared with SE group,ES group,ME group and CO group can significantly reduce the number of inflammatory cells in alveoli at the same time point(P< 0.05).At 6h and 12 h,the number of BAL inflammatory cells in the CO group was lower than that in the ES group and ME groups(P< 0.05).At 0h,there was no significant difference among the three groups(P> 0.05).7.Comparison of the levels of plasma inflammatory factors: by analyzing the contents of IL-6 and TNF-? in the plasma,except BL group and Se group,the level of IL-6and TNF-? in plasma increased gradually with the delay of intervention time(P< 0.05);Compared with each other,the plasma inflammatory factors in ES group,ME group and CO group were higher than those in BL group and lower than those in SE group(P< 0.05),At 6h and 12 h,the level of IL-6 in CO group was lower than that in ES group and me group(P < 0.05);At 0h,There was no significant difference in IL-6 levels among es group,me group and co group(P > 0.05).The level of TNF-? in CO group was lower than that in ES group and me group at 12h(P< 0.05),and there was no significant difference between ES group,me group and co group at 0h and 6h(P> 0.05).8.HE staining: The injury score of SE group was significantly higher than that of BL group at different intervention time points(P < 0.05);the injury score of CO group at 0h was lower than that of ES group and ME group(P < 0.01);at 6h and 12 h,the injury score of CO group was significantly lower than that of ME group(P < 0.05),but there was no significant difference compared with ES group(P > 0.05);At the same time,the injury scores of ES group,me group and co group were significantly higher than BL group,significantly lower than se group(P < 0.05);There was no significant difference between ES group and me group(P > 0.05).The earlier the intervention time was,the lower the injury score was(P < 0.05).9.Relative expression of IL-6 and TNF-? m RNA: The results of IL-6 and TNF-?m RNA expression in lung tissue homogenate showed that at the same intervention time point,the expression of IL-6 and TNF-? m RNA in SE group was significantly higher than that in BL group,while the expression of IL-6 and TNF-? m RNA in ES group and ME group was lower than that in SE group(P< 0.05),At 6h and 12 h,the expression of IL-6 and TNF-? m RNA in CO group was further reduced(P< 0.05).At0 h,there was no significant difference between ES group,ME group and CO group;The m RNA expression of ES group,me group and co group had the same change trend at different intervention time points,that is,with the delay of intervention time points,the m RNA expression gradually increased(P< 0.05).10.Relative expression of p65 and I?B-?:The expression of p65 was the lowest in BL group and the highest in SE group when compared with the same intervention time point.The expression of p65 in ES group,ME group and CO group was significantly lower than that in SE group and higher than that in BL group.The expression of p65 in CO group was significantly lower than that in ES group and me group(P< 0.05).Compared with different intervention time points,the relative expression of p65 protein in ES group,ME group and CO group increased with the delay of intervention time points(P<0.05).The change trend of I?B-? is just opposite to p65.Conclusion:Both esmolol and methylprednisolone have protective effects on sepsis acute lung injury,which is related to the initial time of intervention,and the earlier they are used,the better these protective effect on lung injury.Esmolol combined with methylprednisolone have better protective effects on acute lung injury than single drug.The mechanism of esmolol and methylprednisolone in reducing inflammatory lung injury may be related to the inhibition of NF-? B signal pathway and the release of inflammatory factors.