TLR4/NF-κB通路在异氟醚预处理对大鼠心肌缺血再灌注损伤保护中的作用

Isoflurane preconditioning protects myocardium after ischemic-reperfusion injury in rats through toll-like receptor 4/NF-κB signaling pathway

目的探讨TLR4/NF-κB信号通路在异氟醚预处理对大鼠心肌缺血再灌注损伤保护中的作用,为防治心肌缺血/再灌注损伤提供新的理论依据。方法将成年雄性SD大鼠40只随机分成5组:假手术组(S组)、缺血再灌注损伤组(IR组)、异氟醚预处理组(ISO组)、TLR4抑制剂TAK-242组(T组)、异氟醚+TAK-242预处理组(ISOT组),每组8只。S组左冠状动脉前降支只穿线不结扎;IR组只进行缺血再灌注;ISO组:吸入1.0MAC异氟醚30min,停止吸入15min;T组:予尾静脉注射TLR4受体抑制剂TAK-242(10mg/kg);ISOT组:吸入异氟醚前1min尾静脉注射TAK-242(10mg/kg),之后建立缺血再灌注模型。再灌注完成后取出心脏,HE染色在光学显微镜下观察心肌组织形态学变化并测定各组大鼠心肌梗死面积;分别采用RT-PCR和Western blot技术检测心肌组织中TLR4受体在转录和蛋白水平上的变化,以及NF-κB的表达情况。结果与IR组比较,其余各组TLR4 m RNA和TLR4表达水平均明显降低(均P<0.01);与ISO、T组比较,ISOT组TLR4 mRNA和TLR4表达显著降低(均P<0.01);与ISO组比较,T组TLR4 mRNA和TLR4表达显著降低(均P<0.01)。与IR组比较,其余各组NF-κB的表达显著降低(P<0.01);与T、ISOT组比较,ISO组NF-κB的表达均明显降低(均P<0.01)。与IR组比较,其余各组心肌梗死面积均明显减少(P<0.01);与ISO组和T组比较,ISOT组心肌梗死面积显著减小(P<0.01);而ISO组和T组比较差异无统计学意义(P>0.05)。结论 TLR4/NF-κB信号通路参与了异氟醚预处理对大鼠心肌缺血再灌注损伤的保护作用。

Objective To investigate the effect of isoflurane preconditioning on myocardium after ischemia/reperfusion （I/R） injury in rats and its relation to toll-like receptor 4 （TLR4）/NF-κB signaling pathway.Methods Forty SD rats were randomly divided into five groups with 8 in each：sham-operated group （group S）,ischemia/reperfusion group （group IR）,isoflurane preconditioning group（group ISO）,TAK-242 inhibitor group（group T） and isoflurane preconditioning and TAK-242 inhibitor group （group ISOT）.The rats were given 1.0 MAC isoflurane inhalation for 30min before I/R induced;TLR4 receptor inhibitor TAK-242 10mg/kg was injected through tail vein 1 minute before inhaling isoflurane,and ischemic/reperfusion model was induced by ligation of anterior descending coronary artery.The myocardial tissue samples were obtained at the end of reperfusion.The size of myocardial infarction was measured by light microscope with HE staining.The expression of TLR4 mRNA and protein in myocardial tissue was detected by RT-PCR and Western blot,respectively,the expression of NF-κB was detected by Western blotting.Results Compared with group IR,the expression levels of TLR4 mRNA and protein was significantly lower in other groups （P〈0.01）,compared with groups ISO and T,the expression of TLR4 mRNA and protein was down-regulated significantly （P〈0.01） in group ISOT,compared with group ISO,the expression of TLR4 mRNA and protein was down-regulated significantly （P〈0.01） in group T.Compared with group IR,the expression of NF-κB protein in other groups decreased significantly（P〈0.01）,compared with groups T and ISOT,the expression of NF-κB protein in group ISO decreased significantly （P〈0.01）.Compared with group IR,the size of myocardial infarction in other experimental groups were significantly reduced （P〈0.01）,compared with group ISO and T,the infarct size was significantly reduced in group ISOT （P〈0.01）,and there was no difference between group ISO and group T （P 〉0.05）.Conclusion TLR4/NF-κ B signaling may be involved in protective effect of isoflurane preconditioning against myocardial ischemia-reperfusion injury in rats.