心肌梗死后交感神经的重构现象

Study of sympathetic neural remodeling after myocardial infarction in rats

目的 探讨大鼠心肌梗死后室性心律失常发生的交感神经重构机制及 β受体阻滞剂在心肌梗死后交感神经重构中的作用。方法 通过抗酪氨酸羟化酶的免疫组化染色方法 ,检测心肌梗死后 3d、 7d、 30d及普奈洛尔干预后的左心室梗死周围、室间隔和右心室中交感神经支配的密度和范围。结果 心肌梗死后 3d ,交感神经支配密度在梗死周围和室间隔中降低 ,在右心室中增加 (P <0 0 5 ) ;心肌梗死后 7d ,梗死周围、室间隔和右心室中交感神经支配密度和范围均增加 ;心肌梗死后30d时上述变化更加明显 (P <0 0 1)。普奈洛尔促使心肌梗死后各部位心室中交感神经支配的范围趋于正常化 ,并降低室间隔和右心室中的交感神经支配密度 (P <0 0 1)。结论 左心室心肌梗死后的梗死周围、室间隔和右心室中出现交感神经重构现象 ,β受体阻滞剂能改善心肌梗死后的交感神经重构。

Objective To evaluate the sympathetic neural remodeling mechanism of ventricular arrhythmia after left ventricular myocardial infarction in rats and the effect of β-blocker on remodeling. Methods After treated with ligating the proximal portion of the left coronary artery or sham-operation procedure,the rats were classifed into 4 infarction groups and 4 control groups (3 days,7 days,30 days after surgery and propranolol taken orally). The density and extent of sympathetic innervation in left ventricular periinfarcted area、ventricular septum and right ventricle in different groups were examined by tyrosine hydroxylase immunohistochemistry. Results The density of sympathetic innervation were lower in periinfarcted area and ventricular septum,and higher in right ventricle in infarction groups compared with control group 3 days after surgery (P<0.05). The density and extent of sympathetic innervation in periinfarcted area、ventricular septum and right ventricle were higher in infarction group compared with control group 7 days after surgery,that were more significant 30 days later (P<0.01). Propranolol can decrease the density of sympathetic innervation in ventricular septum and right ventricle (P<0.01),and normalize the extent of sympathetic innervation in the whole ventricle after left ventricular myocardial infarction. Conclusion These data indicate that left ventricular myocardial infarction resulted in sympathetic neural remodeling in periinfarcted area、ventricular septum and right ventricle,β-blocker can play an important role in improving this sympathetic neural remodeling.