目的：探讨肿瘤坏死因子-α（TNF-α）抑制剂（依那西普）通过跨膜蛋白受体Notch1信号通路对小鼠创伤性心肌损伤的保护作用。方法选取c57系清洁级雄性小鼠36只（10~12周龄），采用随机数字表法分为假手术组（腹腔注射5 ml/kg生理盐水）、对照组（腹腔注射5 ml/kg生理盐水）、依那西普组（建立创伤后心肌缺血再灌注损伤模型，依那西普8 mg/kg）各12只，采用酶联免疫吸附法（ELISA）检测各组小鼠再灌注30 min后的血浆TNF-α、3 h后的血清心肌肌钙蛋白I（cTnI）浓度，测定各组再灌注24 h后的左室射血分数（LVEF）、采用TUNEL染色法检测各组心肌细胞凋亡率、采用TTC双染色检测各组心肌梗死面积比值，采用免疫印迹法（Western-blot）检测再灌注6 h后心肌跨膜蛋白受体Notch1胞内活性片段（Notch1-ICD）、细胞凋亡相关蛋白3（caspase-3）的表达。结果对照组、依那西普组大鼠的血浆TNF-α、血清cTnI水平、心肌Notch1-ICD、caspase-3蛋白表达水平、心肌细胞凋亡率、心肌梗死面积比值均显著高于假手术组（P＜0.05）；依那西普组血浆TNF-α、血清cTnI水平、心肌caspase-3蛋白表达水平、心肌细胞凋亡率、心肌梗死面积比值显著低于对照组（P＜0.05），Notch1-ICD蛋白表达水平、LVEF值显著的高于对照组（P＜0.05）。结论 TNF-α抑制剂对创伤后心肌缺血再灌注损伤心肌具有保护作用，其作用机制与激活Notch1信号通路以调节caspase-3蛋白表达水平有关。%Objective To investigate the protective effect of tumor necrosis factor-α (TNF-α) inhibitor (etanercept) through the transmembrane receptor signaling pathway on traumatic myocardial injury in mice.Methods 36 male mice(10-12 weeks of age) were randomly divided into sham operation group(intraperitoneal injection of 5 ml/kg normal saline), control group (post - traumatic myocardial ischemia - reperfusion injury were prepared, intraperitoneal injection of 5 ml/kg normal saline) and etanercept group (post - traumatic myocardial ischemia -reperfusion injury were prepared, intraperitoneal injection Etanercept 8 mg/kg). TNF-αlevel at 30 minutes after reperfusion and serum cardiac troponin I (cTnI) concentration at 3 hours after reperfusion were measured by enzyme-linked immunosorbent assay (ELISA). The left ventricular ejection fraction (LVEF) was measured 24 hours after reperfusion. TUNEL staining was used to measure the apoptotic rate of cardiomyocytes. The area of myocardial infarction was determined by TTC double staining. The expression levels of intracellular domain of Notch1 (Notch1-ICD) and caspase-3 were measured by western blot.Results The levels of serum TNF-α and serum cTnI, and caspase-3, apoptotic rate of cardiomyocytes and the area of myocardial infarction in the control group and etanercept group were significantly higher than those in the sham operation group (P<0.05). The levels of serum TNF-α and serum cTnI, the expression level of caspase-3, apoptotic rate of cardiomyocytes and the area of myocardial infarction in the etanercept group were significantly lower than those in the control group (P<0.05). The value of LVEF and the expression level of Notch1-ICD were significantly higher than those in the control group (P<0.05).Conclusion TNF-αinhibitors have protective effects on myocardium after myocardial ischemia-reperfusion injury, and its mechanism is related to activation of Notch1 signaling pathway to regulate the expression of caspase-3 protein.
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