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目的:探讨不同浓度Semaphorin 3A(Sema 3A)对大鼠心肌梗死慢性期梗死周边区交感神经重构及心室颤动阈值(室颤阈值)的影响。方法:80只大鼠随机分为两组。心梗组(20只):结扎冠状动脉前降支;Sema 3A组(60只):结扎冠状动脉前降支后于梗死周边区分别注入不同浓度的Sema 3A。8周后测定大鼠梗死周边区室颤阈值,免疫组化染色检测生长相关蛋白43(GAP43)和酪氨酸羟化酶(TH)阳性纤维密度。结果:室颤阈值在Sema 3A注射组中随药物浓度增加而升高,1.0mg/L浓度组相比心梗组有明显提高(P<0.05)。Sema 3A注射组GAP43和TH神经纤维密度与心梗组差异明显(P<0.05);且随药物浓度提高神经纤维密度呈下降趋势,在药物浓度达到1.0mg/L时表现显著(与1.0mg/L组相比P<0.05)。结论:不同浓度的Sema 3A对室颤阈值有不同的提升效应,而对大鼠心肌梗死后交感神经重构产生不同的抑制作用。
Objective: To investigate the effect of Semaphorin 3A (Sema 3A) at different concentrations on sympathetic remodeling and ventricular fibrillation threshold (VF) in peripheral infarction of chronic myocardial infarction in rats. Methods: Eighty rats were randomly divided into two groups. The rats in the MI group (20 rats): the anterior descending coronary artery was ligated; the Sema 3A group (60 rats): the anterior descending coronary artery was ligated with different concentrations of Sema 3A in the peripheral area of infarction. After 8 weeks, the threshold value of ventricular fibrillation in peripheral infarction area was determined. The expression of GAP43 and TH positive fibers were detected by immunohistochemistry. Results: The threshold of ventricular fibrillation increased with the increase of drug concentration in the Sema 3A injection group, and was significantly increased in the 1.0 mg / L concentration group compared with the myocardial infarction group (P <0.05). The density of GAP43 and TH nerve fibers in myocardial infarction group were significantly different from those in myocardial infarction group (P <0.05), and the density of nerve fibers decreased with the increase of drug concentration in Sema 3A injection group. The drug concentration of 1.0mg / L group compared to P <0.05). CONCLUSIONS: Different concentrations of Sema 3A have different promotion effects on the threshold of ventricular fibrillation, but have different inhibitory effects on sympathetic nerve remodeling after myocardial infarction in rats.