大鼠心肌梗死后神经生长因子受体的表达

Expression of nerve growth factor receptors after myocardial infarction in rats

目的:观察大鼠心肌梗死(MI)后不同时间点(1 d、7 d、30 d)神经生长因子(NGF)受体的表达情况。方法:采用开胸结扎冠状动脉法建立大鼠MI模型,在术后1 d、7 d、30 d处死动物,取出心脏,假手术大鼠(只开胸不结扎)作为对照研究。分别用实时定量PCR方法及Western blot方法检测梗死边缘区心肌中高亲和性受体酪氨酸激酶A(Trk A)和低亲和力神经受体P75(P75NTR)mRNA及蛋白的表达。结果:与对照组相比,MI后1 d,7 d,30 d,P75NTR mRNA及蛋白表达都没有明显差异,Trk A mRNA及蛋白表达在MI后7 d及30 d较对照组明显下降(P<0.05),而且呈动态下降趋势。结论:大鼠MI后心脏NGF受体Trk A和P75NTR的表达发生了变化,P75NTR表达程度在NGF介导的MI后交感神经增生中不起决定作用。

AIM：Nerve growth factor （NGF） regulates myocardial sympathetic innervation and induces sympathetic nerve hyperinnervation after myocardial infarction. Its neutrophic effects by binding to specific cell surface receptors, including the high-affinity receptor tyrosine kinase A （TrkA） and the NGF low-affinity receptor P75NTR. However, it is unclear whether TrkA and P75NTR are altered after acute myocardial infarction. The aim of this study was to determine the dynamic change of NGF receptor expression from 1 day to 30 days after myocardial infarction in the rat. METHODS： Rats were subjected to MI and killed 1, 7, 30 days after MI, sham-operated rats were considered as control. TrkA and P75NTR mRNA expression and protein levels in the infarcted border myocardium were measured by real-time PCR and Western blot. RESULTS： We found that after MI, both P75NTR mRNA expression and protein levels showed no significant changes when compared with control group at all time points, whereas TrkA expression decreased at day 7 after MI and continued to decrease at day 30 （P〈0.05）. CONCLUSION： A specific temporal pattern of TrkA/p75NTR occurred in post-MI rats, and the p75NTR may not be crucial, mediating sympathetic innervation after MI.