雷公藤甲素对急性心肌梗死小鼠心肌损伤的影响

Effects of triptolide on myocardial injury in mice with acute myocardial infarction

目的:探讨雷公藤甲素(triptolide,TPL)对急性心肌梗死(acute myocardial infarction,AMI)小鼠受损心肌的保护作用。方法:将50只C57BL/6J小鼠按照随机数字表法分成6组:DMSO+假手术组(n=5)、高剂量TPL+假手术组(n=5)、DMSO+手术组(n=10)、低剂量TPL+手术组(n=10)、中剂量TPL+手术组(n=10)和高剂量TPL+手术组(n=10)。术前3 d腹腔注射不同剂量的TPL,通过结扎左冠状动脉前降支构建AMI模型。采用HE染色检测AMI诱导的心肌损伤,免疫组化检测AMI后心肌组织中中性粒细胞和巨噬细胞的浸润,Masson染色检测AMI后胶原纤维表达,Western blot检测AMI后心肌组织中p-IκBα、p-P65、Bax和Bcl-2的蛋白水平,RT-qPCR法检测AMI后炎症因子白细胞介素1(interleukin-1,IL-1)、IL-6和肿瘤坏死因子α(tumor necrosis factor-α,TNF-α),以及纤维化相关因子结缔组织生长因子(connective tissue growth factor,CTGF)、骨膜蛋白(periostin)、I型胶原蛋白(collagen type Ⅰ,Col Ⅰ)和Col Ⅲ的mRNA表达水平,TUNEL和心肌钙蛋白T(cardiac troponin T,cTnT)双染检测AMI后心肌细胞凋亡情况。结果:TPL预处理可以显著减少小鼠AMI诱导的中性粒细胞和巨噬细胞浸润(P<0.05),抑制NF-κB信号通路激活,减少炎症因子IL-1、IL-6和TNF-α的表达(P<0.05);而在AMI后第7天,TPL预处理可以抑制细胞外基质中CTGF、periostin、Col Ⅰ和Col Ⅲ的表达而减轻心肌纤维化(P<0.05),降低Bax/Bcl-2比值,减少心肌细胞凋亡(P<0.05),从而减轻小鼠AMI诱导的心肌损伤。结论:TPL可能通过抑制NF-κB途径减轻小鼠AMI诱导的炎症反应及心肌纤维化,减少心肌细胞凋亡,抑制心梗后心肌负性重构。

AIM:To investigate the protective effect of triptolide(TPL)on injured myocardium in mice with acute myocardial infarction(AMI).METHODS:Fifty C57BL/6J mice were divided into 6 groups according to random number table method:DMSO+sham group,high-dose TPL+sham group,DMSO+AMI group,low-dose TPL+AMI group,medium-dose TPL+AMI group and high-dose TPL+AMI group. Different doses of TPL were injected intraperitoneally 3 d before surgery. The model of mouse AMI was established by ligating the anterior descending branch of left coronary artery.Myocardial injury induced by AMI was detected by HE staining. The infiltration of neutrophils and macrophages in myocardial tissue after AMI was detected by immunohistochemistry. Masson staining was used to detect collagen fiber staining.The protein levels of p-IκBα,p-P65,Bax and Bcl-2 in myocardial tissue after AMI were detected by Western blot. The mRNA levels of interleukin-1(IL-1),IL-6,tumor necrosis factor-α(TNF-α),connective tissue growth factor(CTGF),periostin,collagen type Ⅰ(Col Ⅰ)and Col Ⅲ after AMI were detected by RT-qPCR. The apoptosis of cardiomyocytes was detected by TUNEL and cardiac troponin T(cTnT)double staining.RESULTS:Pretreatment with TPL significantly reduced the infiltration of neutrophils and macrophages induced by AMI(P<0. 05),inhibited NF-κB signaling pathway,and decreased the expression of inflammatory factors IL-1,IL-6 and TNF-α(P<0. 05). On the 7th day after AMI,TPL inhibited the expression of CTGF,periostin,Col Ⅰ and Col Ⅲ,and attenuated myocardial fibrosis(P<0. 05). Additionally,TPL decreased the Bax/Bcl-2 ratio and reduced cardiomyocyte apoptosis(P<0. 05),so as to reduce AMI-induced myocardial injury.CONCLUSION:Pretreatment with TPL attenuates AMI-induced inflammatory response in mice by inhibiting the NF-κB pathway,and reduced myocardial fibrosis and cardiomyocyte apoptosis,thereby inhibiting myocardial negative remodeling after AMI.