远隔缺血预处理联合七氟醚后处理对大鼠心肌缺血-再灌注时TLR4/NF-κBp65的影响

Effects of remote ischemic preconditioning and sevoflurane postconditioning on TLR4/NF-κBp65 during myocardial ischemia-reperfusion in rats

目的评价远隔缺血预处理联合七氟醚后处理对大鼠心肌缺血-再灌注时的影响及其机制。方法成年雄性SD大鼠75只,体重250~300 g,成功建立Langendorff离体灌注模型的大鼠心脏之后,采用随机数字表法分为五组(n=15):对照组(C组)、缺血-再灌注组(IR组)、远隔缺血预处理组(R组)、七氟醚后处理组(S组)和远隔缺血预处理+七氟醚后处理组(RS组)。C组持续灌注150 min。IR组给予缺血-再灌注处理。R组给予远隔缺血预处理后,给予缺血-再灌注处理。S组给予缺血-再灌注处理,于再灌注初给予经2.4%七氟醚饱和的K-H液灌注2 min。RS组给予远隔缺血预处理后给予缺血-再灌注处理,于再灌注初给予经2.4%七氟醚饱和的K-H液灌注2 min。再灌注末,采用1%2,3,5氯化三苯基四氮唑测定心肌梗死体积百分比。采用ELISA法检测肌酸激脢同工酶(CK-MB),白细胞介素-8(IL-8),白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)浓度。采用Western blot法测定Toll-样受体4(TLR4),高迁移率族蛋白B1(HMGB-1),髓样分化因子88(MyD88),人核因子κB抑制蛋白α(IKB-α),核因子-κBp65(NF-κBp65),半胱氨酸天冬氨酸蛋白酶3(Caspase3),B淋巴细胞瘤基因-2(Bcl-2)和Bcl-2相关蛋白(BAX)的蛋白含量。采用HE染色观察心肌组织形态学变化。结果与C组比较,IR组、R组、S组和RS组心肌梗死体积百分比明显增加,CK-MB、IL-8、IL-6和TNF-α浓度,TLR4、HMGB-1、MyD88、NF-κBp65、Caspase3和BAX蛋白含量均明显升高,IKB-α和Bcl-2蛋白含量明显降低(P<0.05),心肌组织病理形态明显恶化。与IR组比较,R组和S组心肌梗死体积百分比明显减小,CK-MB、IL-8、IL-6和TNF-α浓度,TLR4、HMGB-1、MyD88、NF-κBp65、Caspase3和BAX蛋白含量均明显降低,IKB-α和Bcl-2蛋白含量明显升高(P<0.05),心肌组织病理形态明显改善。与R组和S组比较,RS组心肌梗死体积百分比明显减小,CK-MB、IL-8、IL-6和TNF-α浓度,TLR4、HMGB-1、MyD88、NF-κBp65、Caspase3和BAX蛋白含量均明显降低,IKB-α和Bcl-2蛋白含量明显升高(P<0.05),心肌组织病理形态明显改善。结论远隔缺血预处理和七氟醚后处理均可抑制TLR4/NF-κBp65信号通路和炎症反应,明显减轻大鼠心肌缺血-再灌注损伤。两者联合处理对心肌的保护作用明显优于单独处理。

Objective To evaluate the effects and mechanism of remote ischemic preconditioning and sevoflurane postconditioning on myocardial ischemia-reperfusion injury in rats. Methods Seventy-five adult male Sprague-Dawley rats, weighing 250-300 g, were used and the Langendorff isolated perfusion model of rat hearts was successfully established. They were randomly divided into five groups(n = 15): control group(group C), ischemia-reperfusion group(group IR), remote ischemic preconditioning group(group R), sevoflurane postconditioning group(group S) and remote ischemic preconditioning+sevoflurane postconditioning group(group RS). Group C was continuously perfused for 150 min. Group IR was given the ischemia-reperfusion treatment. Group R was given ischemia-reperfusion treatment after remote ischemic preconditioning. Group S was given ischemia-reperfusion treatment, and was perfused with 2.4% sevoflurane-saturated K-H solution for 2 min at the beginning of reperfusion. Group RS was given ischemia-reperfusion treatment after remote ischemic preconditioning, and was perfused with 2.4% sevoflurane-saturated K-H solution for 2 min at the beginning of reperfusion. At the end of reperfusion, the myocardial infarct size was determined by using 1% 2,3,5-triphenyltetrazolium chloride. The concentrations of creatine kinase isoenzymes(CK-MB), interleukin-8(IL-8), interleukin-6(IL-6) and tumor necrosis factor-α(TNF-α) were detected by ELISA. The expressions of Toll-like receptor 4(TLR4), high mobility group protein B1(HMGB-1), Myeloid differentiation factor 88(MyD88), IKB-α,NF-κBp65, Caspase3, BAX and Bcl-2 protein were detected by Western Blot. Myocardial morphological changes were observed by HE staining. Results Compared with group C, the myocardial infarct size, the concentrations of CK-MB, IL-8, IL-6 and TNF-α, and the protein expressions of TLR4, HMGB-1, MyD88, NF-κBp65, Caspase3 and BAX were significantly increased in group IR, group R, group S and group RS, the expression of IKB-α and Bcl-2 protein was significantly decreased(P<0.05), and the pathological morphology of myocardial tissue was significantly deteriorated. Compared with group IR, the myocardial infarct size, the level of CK-MB, IL-8, IL-6, TNF-α, TLR4, HMGB-1, MyD88, NF-κBp65, Caspase3 and BAX were significantly decreased in group R and group S, and the protein expression of IKB-α and Bcl-2 was elevated(P<0.05), the myocardium pathological morphology was significantly improved. Compared with group R and group S, the myocardial infarct size, and the level of CK-MB, IL-8, IL-6, TNF-α, TLR4,HMGB-1,MyD88,NF-κBp65, Caspase3 and BAX were siginificantly decreased in group RS, and the protein expression of IKB-α and Bcl-2 was elevated(P<0.05), the myocardium pathological morphology was improved. Conclusion Remote ischemic preconditioning combined with sevoflurane postconditioning could inhibite TLR4/NF-κBp65 signaling pathway and inflammatory response, and significantly reduce myocardial ischemia-reperfusion injury in rats. And the combined treatment of the two is significantly better than the single treatment.