丹皮酚对心肌缺血再灌注损伤保护中Toll样受体4、心肌焦亡影响的作用机制

Mechanism of influence on paeonol on TLR4 and myocardial pyrosis in protection of myocardial ischemia-reperfusion injury

目的:探讨丹皮酚对大鼠心肌缺血再灌注损伤(MIRI)的作用机制及对Toll样受体4(TLR4)、细胞焦亡的影响。方法:将SD大鼠随机分为假手术组、缺血再灌注组、丹皮酚低剂量组(15 mg/kg)、丹皮酚高剂量组(30 mg/kg)。药物干预后,结扎左冠脉前降支0.5 h,再灌注4 h。再灌注结束后,采用生化分析法测定肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)水平;2,3,5-氯化三苯基四氮唑蓝(TTC)染色法测定心肌梗死面积,免疫组化法测定TLR4蛋白水平;免疫印迹(Western blot)法检测心肌组织NOD样受体家族Pyrin域3(NLRP3)、IL-1β、凋亡相关斑点蛋白(ASC)以及半胱天冬酶(Caspase)-1的表达。结果:与缺血再灌注组比较,丹皮酚低剂量组、丹皮酚高剂量组再灌注后LDH、CK-MB活性下降,心肌梗死面积减小,心肌组织TLR4、NLRP3、Caspase-1、ASC、IL-1β表达水平降低,差异有统计学意义(均P<0.05)。丹皮酚高剂量组的上述指标均低于丹皮酚低剂量组,差异有统计学意义(均P<0.05)。结论:丹皮酚预处理可抑制TLR4表达,下调NLRP3/Caspase-1介导的细胞焦亡,降低CK-MB、LDH的活性,减少大鼠心肌梗死面积,阻止心肌缺血再灌注损伤进程,保护心肌组织。

Objective:To observe the mechanism of paeonol on myocardial ischemia-reperfusion injury(MIRI),and effects on toll like receptor 4(TLR4)and cell pyrolysis in rats.Methods:SD rats were randomly divided into sham operation group,ischemia-reperfusion group,low-dose paeonol group(15 mg/kg)and high-dose paeonol group(30 mg/kg).After drugs intervention,left anterior descending coronary were ligating for 0.5 h and reperfusion for 4 h.After reperfusion,the levels of creatine kinase isoenzyme(CK-MB),lactate dehydrogenase(LDH)were determined by biochemical assays.Myocardial infarct area were measured by 2,3,5-Chlorinated triphenyl tetraazazole blue(TTC)staining method.The TLR4 protein level was determined by immunohistochemistry and the nod like receptor family pyrin domain containing 3(NLRP3),IL-1β,apoptosis-associated speckle protein(ASC)and Caspase-1 in myocardial tissue were measured by Western blot.Results:Compared with the ischemia-reperfusion group,the activities of LDH and CK-MB in the low-dose paeonol group and high-dose paeonol group were decreased,the area of myocardial infarction decreased,and the levels of TLR4,NLRP3,Caspase-1,ASC,IL-1βin myocardial tissue decreased after reperfusion,difference statistically significant(all P<0.05).Above indicators in the high-dose paeonol group were lower than those in the low-dose paeonol group,difference statistically significant(all P<0.05).Conclusion:Paeonol pretreatment can inhibit TLR4 expression,down-regulate cellular pyroptosis which NLRP3/Caspase-1 mediated,reduce CK-MB and LDH activity,reduce the area of myocardial infarction,prevent progression of myocardial ischemia and reperfusion damage in rats,and protect myocardial tissue.