Objective: To observe the effect of electroacupuncture(EA) preconditioning on expression of Caspase-1, Gasdermin D(GSDMD) and interleukin-1β(IL-1β) in myocardial tissue of myocardial ischemia reperfusion injury (MIRI) rats in order to explore its underlying mechanisms in resisting MIRI.
Methods: Forty male rats were randomly divided into 4 groups: normal control (normal), sham operation (sham), MIRI model and EA groups. The MIRI model was established by ligation of the left anterior descending branch of the left coronary artery for 30 min and perfusion. EA (2 Hz/100 Hz, 1 mA) was applied to bilateral "Neiguan" (PC6) for 20 min, once a day for 3 consecutive days. The echocardiography was used to analyze the left ventricular end-diastolic dimension (LVEDD), left ventricular end-systolic dimension (LVESD) and left ventricular ejection fraction (LVEF, by using Teichholz formula) 4 h after modeling. The myocardial TTC staining was used to observe the proportion of the infarct area, and Western blot was used to detect the expression levels of GSDMD, Caspase-1, IL-1β proteins in the myocardium.
Results: Compared with the normal group, the immunoactivity of GSDMD was increased in the sham group (P<0.05). Compared with the sham group, the LVEF was significantly decreased (P<0.000 1), while the myocardial infarction area, immunoactivity of GSDMD, and the expression levels of Caspase-1, GSDMD and IL-1β proteins were considerably increased in the model group (P<0.000 1, P<0.001). In comparison with the model group, the decreased ejection fraction and the increased myocardial infarction area, and Caspase-1, GSDMD and IL-1β expression were reversed in the EA group (P<0.001, P<0.000 1, P<0.01).
Conclusion: EA preconditioning may ameliorate myocardial injury in MIRI rats which may be associated with its function in down-regulating the expression of myocardial Caspase-1 protein to reduce cardiomyocyte pyroptosis.
目的：观察电针预处理对心肌缺血再灌注损伤(MIRI)大鼠心肌细胞焦亡相关蛋白半胱氨酸蛋白酶-1(Caspase-1)、Gasdermin D(GSDMD)、白细胞介素-1β(IL-1β)的影响, 探讨电针预处理减轻MIRI损伤的可能机制。方法：SD大鼠随机分为空白组、假手术组、模型组、电针组, 每组10只。电针组电针大鼠双侧“内关”, 每次20 min, 每日1次, 连续3 d。采用冠状动脉左前降支结扎法复制MIRI大鼠模型。采用超声心动图观察造模4 h后大鼠左心室射血分数(LVEF)以评估心功能；TTC染色法观察大鼠心肌梗死面积；免疫组织化学法观察大鼠心肌组织中GSDMD表达情况；Western blot法检测心肌组织GSDMD、Caspase-1、IL-1β蛋白表达水平。结果：与空白组相比, 假手术组心肌组织GSDMD表达升高(P<0.05)。与假手术组相比, 模型组大鼠术后4 h时LVEF明显下降(P<0.000 1), 梗死面积增大(P<0.000 1), 心肌组织GSDMD表达显著升高(P<0.000 1), 心肌GSDMD、Caspase-1、IL-1β蛋白表达升高(P<0.001, P<0.000 1)。与模型组相比, 电针组大鼠术后4 h时LVEF升高(P<0.001), 梗死面积缩小(P<0.000 1), 心肌组织GSDMD表达降低(P<0.001), 心肌GSDMD、Caspase-1、IL-1β蛋白表达降低(P<0.01, P<0.001)。结论：电针预处理可能通过下调Caspase-1蛋白的表达, 降低心肌细胞焦亡水平, 从而改善MIRI损伤。.
Keywords: Caspase-1; Electroacupuncture preconditioning; Gasdermin D (GSDMD); Myocardial ischemia reperfusion injury; Pyroptosis.