鼠源性神经生长因子在缺氧缺血性脑损伤神经修复中作用机制的探讨

A approach on mechanism of action of mNGF in neural recovery of HIBD

目的探讨鼠源性神经生长因子(NGF)治疗新生鼠缺氧缺血性脑损伤(HIBD)的作用机制。方法新生7 d SD乳鼠120只,随机分mNGF干预组、HIBD组和正常对照组各40只,各组又分为7、14、21 d组和28 d组。干预组在HIBD模型建立后予以mNGF臀部肌肉注射20 n.gg-1.d-1,5 d,采用免疫组化检测Nestin蛋白表达;采用TUNEL实验检测神经细胞的凋亡。结果3组Nestin在海马的分布存在差异,对照组主要分布在分子层、锥体细胞层和内颗粒细胞层,HIBD组主要分布在海马CA1、CA2、CA3区,干预组主要分布在DG、CA3区;在7 d时干预组Nestin蛋白表达高于HIBD组及对照组(P<0.01);在14 d时干预组高于HIBD组及对照组(P<0.05);在21 d时3组之间无差异(P>0.05);在28 d时干预组高于HIBD组及对照组(P<0.05)。干预组凋亡神经细胞在7 d时低于HIBD组,高于对照组,差异有统计学意义(P均<0.01)。干预组14 d时与HIBD组及对照组之间差异有统计学意义(P<0.05),此后21、28 d 3组凋亡神经细胞均减少,但干预组在每一时相点与HIBD组及对照组之间差异有统计学意义(P<0.01)。结论mNGF能够增加新生大鼠HIBD模型神经干细胞s在海马的增殖,抑制神经细胞的凋亡。

Objective To investigate effect of mouse nerve growth factor （mNGF） in hypoxic - ischemic brain damage （HIBD） model of neonatal rat. Methods One hundred and twenty 7 days old neonatal rats were randomly divided into control, HIBD and interventional groups, each composed of 40 neonatal rats. After HIBD model established, mNGF was intramuscularly injected to interventional group at gluteal muscle continue five days, 20 ng.g^-1.d^-1. Every group was further randomly divided into 7, 14, 21 and 28 days old groups. Nestin distribution was determined by immunohistochemical method. Apoptosis of nerve cells was determined by TUNEL. Results There was a difference in hippocampus distribution of Nestin among three groups. Nestin distributed in molecular, pyramidal and internal granular layer in control groups ; in the region of CA1, CA2 and CA3 in HIBD groups and DG and CA3 in interventional groups. The expression of nestin protein was increased in interventional group compared with control group and HIBD group, statistical significant in 7 （P 〈 0. 01 ）, 14 （P 〈 0. 05 ） and 28 days old rats （P 〈 0. 05 ） ; no difference in 21 days old rats （ P 〉 0.05 ）. Apoplosis of neural ceils was increased in HIBD group, it had a marked difference in 7 days old neonatal rats among 3 groups （P 〈 0. 01 ）; statistical significant different among 14 days old groups （P 〈 0. 05 ）. The study showed decreased apoptosis in 21 days and 28 days old groups, but it still showed a marked difference in neural cell apoptosis of interventional group compared to rest of age matched groups （P 〈 0. 01 ）. Conclusion mNGF can increase proliferation of neural stem cells of HIBD in neonatal rat and inhibit apoptosis of neural ceils in hippocampus.