ERK1／2信号转导通路在大鼠冠状动脉微栓塞致心肌炎症及心功能损伤的作用机制  

Myocardial inflammation and injury induced by coronary microembolizafion in rats： role of ERK1/2 signaling pathway

作　　者：李浪[1] 黎东华[1] 曲楠[1] 文伟明[1] 黄伟强[1] 刘唐威[1] 

机构地区：[1]广西医科大学第一附属医院心内科广西心血管病研究所,南宁530021

出　　处：《中华医学杂志》2010年第8期558-563,共6页National Medical Journal of China

基　　金：广西医疗卫生重点资助课题（重200826）广西优秀人才资助计划（302242）

摘　　要：目的探讨ERK1／2信号通路对大鼠冠状动脉微栓塞（CME）致心肌炎症及心功能损伤的影响。方法SD大鼠分为假手术组、微栓塞组和PD98059组（每组15只）。采用夹闭升主动脉经左心室注射42μm微球0．1ml（3×10^4／ml，3000个）建立大鼠CME模型。PD98059组大鼠术前30min静脉注射细胞外信号调节激酶（ERK1／2）抑制剂PD98059。应用Western印迹和免疫组化检测心肌组织ERK1／2磷酸化程度及分布；采用心脏超声评价心功能；HE染色观察心肌组织炎症细胞浸润情况；FIT—PCR分析肿瘤坏死因子仅（TNF-α）和巨噬细胞移动抑制因子（MIF）mRNA表达水平；应用电泳迁移率转变分析（EMSA）评价核转录因子（NF—κB）的活性。结果微栓塞组比假手术组显著增加心肌组织ERK1／2蛋白磷酸化（0．92±0．10比0．61±0．04）、心肌炎症细胞数[（455±16）个比（47±7）个]、TNF-α mRNA（0．94±0．04比0．60±0．09）和MIFmRNA表达（1．30±0．44比0．63±0．25）以及NF—κB活化（541±25比311±65）（均P〈0．05）；左室射血分数显著下降[（73±3）％比（83±4）％，P〈0．05]。与微栓塞组相比，PD98059组阻断ERK1／2蛋白磷酸化（0．48±0．11比0．92±0．10，P〈0．05），同时抑制了心肌炎症反应，TNF—α mRNA的表达减少（0．42±0．06比0．94±0．04，P〈0.05），但MIFmRNA表达未见明显改变（1．17±0．37比1．30±0．44，P〉0．05），NF-κB的活性降低（105±14比541±25，P〈0．05），炎症细胞浸润减少[（401±12）个比（455±16）个，P〈0．05]，左室射血分数提高[（76±4）％比（73±3）％，P〈0．05]。结论ERK1／2信号转导通路激活是CME致心肌炎症反应及心功能损伤的重要机制，提示抑制ERK1／2信号转导通路可能成为CME防治的潜在新靶点。Objective To determine the role of extracellular signal-regulated kinases1/2 ERK1/ 2） signaling pathway in regulating myocardial inflammation and cardiac function in a rat model of coronary microembolization （CME）. Methods The Sprague-Dawley rats were randomly divided into three groups： sham-operated group（n = 15 ）, coronary microembolization group （ n = 15 ） and PD98059 group （ n = 15 ）. CME model was established by injection of 42 μm microspheres 0. 1 ml （3 × 10^4/ml, 3000） into left ventricle while occluding the ascending aorta. At 30 minutes pre-operation, rats of PD98059 group were injected with PD98059 Ⅳ, a specific ERK1/2 inhibitor. Western blot and immunochemical analysis were used to determine the activation and distribution of ERK1/2. Echocardiography was employed to evaluate cardiac functions. The hematoxylin-eosin staining was used to assay myocardial inflammation. Expression of TNF-α and MIF mRNA was determined by RT-PCR analysis and activity of NF-κB assessed by electrophoretic mobility shift assay. Results In comparison with sham-operated group, CME increased phosphorylation of ERK1/2 （0. 92 ± 0. 10 vs 0. 61 ± 0. 04）, local myocardial inflammatory cells （455 ±16 vs 47 ±7）, expression of TNF-α mRNA （0. 94±0.04 vs 0. 60 ± 0.09 ） and MIF mRNA （ 1.30 ±0.44 vs 0.63 α0. 25） and activity of NF-κB （541 ±25 vs 311 ±65 ） in myocardium （ all P 〈 0.05 ）. All of these dramatically induced cardiac dysfunction [ LVEF （73 ±3） % vs （83 ±4） %, P 〈 0. 05 ]. To compare with CME group, treatment of specific ERK1/2 inhibitor PD98059 blocked the activation of ERK1/2 （0. 48 ±0. 11 vs 0. 92 ±0. 10, P 〈 0. 05 ）, decreased inflammatory cells （401 ±12 vs 455 ±16, P 〈 0. 05 ）, decreased expression of TNF-α mRNA （0. 42 ±0. 06 vs 0. 94 ±0. 04, P 〈 0.05 ） and suppressed activity of NF-κB （105 ±14 vs 541 ±25, P 〈 0. 05 ）. Most importantly, PD98059 treatment ameliorated cardiac functions dramatically [ LVEF （76 ±4）

关 键 词：冠状动脉微栓塞 炎症 细胞外信号调节激酶 肿瘤坏死因子α 

分 类 号：R543[医药卫生—心血管疾病] R542.2[医药卫生—内科学]