心肌梗死后神经生长因子的动态表达及其与交感神经重构的关系

目的 探讨心肌梗死后心肌中神经生长因子(NGF)的动态表达及其在交感神经重构中的作用。方法 从心肌梗死大鼠的梗死周边、室间隔和右心室取材,通过免疫组化染色并结合计算机图像处理技术对心肌中NGF蛋白表达及交感神经支配进行研究。结果 心肌梗死后3天,NGF蛋白的表达在梗死周边心肌中明显减少(P<0.05),在室间隔和右心室中增加;交感神经支配密度在梗死周边和室间隔中明显降低,在右心室中明显增加(P<0.05);室间隔和右心室中交感神经支配与NGF蛋白的表达相关(P<0.05)。心肌梗死后7天,梗死周边心肌中NGF蛋白的表达与交感神经支配密度相关(P<0.01),并均明显高于假手术组(P<0.05)及心肌梗死后3天组(P<0.01);室间隔和右心室中NGF蛋白的表达、交感神经支配密度及范围均明显高于假手术组。心肌梗死后30天,NGF蛋白的表达在梗死周边和室间隔中略有降低,交感神经支配范围及密度在各处心肌中均明显高于心肌梗死后3天、7天(P<0.01)。结论 心肌梗死后心肌中NGF蛋白的表达具有动态过程,并与交感神经失支配、再生和过度支配相关,提示NGF可能在心肌局部发挥神经营养作用进而参与神经重构及神经内分泌的调节过程。

The expression of nerve growth factor and its effect on sympathetic neural remodeling after myocardial infarction in rats

Objective To explore the expression of nerve growth factor (NGF) and its effect on neural remodeling after myocardial infarction in rats. Methods The infracted rats were classifed into 3 groups (3 days, 7days and 30 days after myocardial infarction). By immunohistochemistric method, the expression of NGF protein and sympathetic innervation were examined in peri-infarcted area, ventricular septum, right ventricle ( RV) in different stages and groups. Results The protein of NGF was detected in the cytoplasma of non-infarcted cardiomyocytes. In 3 day group, the expressions of NGF protein were significantly lower in peri-infarcted area and higher in RV and septum than those in control areas (P < 0. 05) , the density of sympathetic nerve decreased in peri-infarcted area and septum and increased in RV significantly, and NGF protein expression correlated with sympathetic innervation in septum and RV (P < 0. 05). In 7 day group, the expression of NGF protein and density of sympathetic nerves in peri-infarcted area, septum and RV were significantly increased (P < 0. 01 ) , NGF protein expression correlated with sympathetic innervation in peri-infarcted area (P < 0. 01) . In 30 day group, the expressions of NGF protein decreased slightly in peri-infarcted area and higher in RV than those in control areas (P < 0. 05 ) , the density of sympathetic nerve was higher than that in 3 and 7 day groups and the extent of innervation was enlarged in each area. Conclusion The expression of NGF protein in myocardium was dynamic and correlated with sympathetic denervation, reinnervation and hyperinnervation, which indicated that NGF might play a nerve-nutritious role and take part in the post-infarcted neural remodeling and neuroendocrine regulation.