Effects of LPS with Different Doses Pretreatment on Inflammatory Factors in Myocardial Ischemia-reperfusion Rats
Bannu·Kuken
XU Changsheng
XU Xia
YANG Mengzhi
YAN Jinlong
Abstract：Objective:To observe the effect of low dose lipopolysaccharide(LPS)pretreatment on inflammatory factors in myocardial ischemia-reperfusion(MIR)rats.Methods:Eighty-four SD rats were divided into sham operation group,model group,verapamil intervention group,0.1 mg/kg LPS intervention group,0.5 mg/kg LPS intervention group,and 1.0 mg/kg LPS intervention group according to numerical random table method.In the sham operation group,equal volume normal saline was injected intraperitoneally 4 hours before the operation,and thoracotomy was performed without MIR operation.The model group was injected with normal saline 24 h before operation and the MIR operation was performed.Verapamil intervention group was intraperitoneally injected with verapamil(2 mg/mL,0.8 mL/kg)at 24 h before surgery.The 0.1 mg/kg LPS intervention group(LPS 0.1 mg/kg),0.5 mg/kg LPS intervention group(LPS 0.5 mg/kg),and 1.0 mg/kg LPS intervention group(LPS 1.0 mg/kg)were intraperitoneally injected respectively.After injection,MIR models were established in all rats except the sham operation group.ECG was detected before and after operation.Echocardiography was performed at 72 h after surgery.Left ventricular ejection fraction(LVEF),left ventricular short axis shortening rate(LVFS),left ventricular end-systolic diameter(LVESD),left ventricular end-diastolic diameter(LVEDD),left ventricular posterior wall thickness-systolic(LVPWs),left ventricular posterior wall thickness-diastolic(LVPWd),left ventricular end-systolic volume(LVESV),and left ventricular end-diastolic volume(LVEDV)were observed.Myocardial infarction area was detected by 2,3,5-triphenyltetrazolium chloride(TTC)staining.Image J software was used to analyze percentage of myocardial infarction area.The pathological changes of myocardial tissue were detected by hematoxylin-eosin(HE)staining.Serum levels of inflammatory factor interferon γ(IFN-γ),interleukin-6(IL-6),and tumor necrosis factor-α(TNF-α)were detected by enzyme-linked immunosorbent assay(ELISA).Results:The results of cardiac ultrasound showed that compared with data in the sham operation group,LVEF and LVFS in the model group decreased,indicating that the heart function was impaired(P＜0.05).Compared with model group,LVEF and LVFS in the verapamil intervention group and LPS intervention groups increased,indicating that cardiac function was improved(P＜0.05).TTC staining showed that compared with sham operation group,myocardial infarction area of model group increased(P＜0.05).Compared with the model group,the myocardial infarction area in the LPS intervention groups decreased(P＜0.05),and the myocardial infarction area of rats in the 1.0 mg/kg LPS intervention group decreased significantly(P＜0.05).The results of HE staining showed that the myocardial fibers in the sham operation group arranged neatly,the morphology of myocardial cells was regular,and there was no clear abnormality in the transverse striae.In the model group,the myocardial fibers disordered and broken severely,with more bleeding foci,serious edema,partial dissolution and necrosis of cardiomyocytes,more nuclear contraction,and scattered or focal infiltration of inflammatory cells in the interstitium.Compared with the model group,0.1 mg/kg LPS intervention group and 0.5 mg/kg LPS intervention group showed without obvious improvement in lesions.The degree of myocardial fibrosis edema,rupture,necrosis,and inflammatory cell infiltration were reduced slightly in the 1.0 mg/kg LPS intervention group and verapamil intervention group.Compared with the sham operation group,the contents of serum IFN-γ,IL-6 and TNF-α in the model group increased(P＜0.05).Compared with the model group,the contents of IL-6 and TNF-α in LPS intervention groups decreased(P＜0.05).Conclusion:Low-dose LPS pretreatment could decrease MIR-induced myocardial injury in rats by inhibiting inflammatory response,thus playing some myocardial protective role.
Keywords：myocardial ischemia-reperfusionmyocardial injurylipopolysaccharideinflammatory factorsratsexperimental study
Publication Date：2025-01-31
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：7( 208-214 )