渗透性开放血脑脊液屏障促进神经生长因子透过的实验研究

Empirical Study on the Effect of Osmotic Opening of Blood Brain Barrier on the Facilitation of Nerve Growth Factor Passing

目的探讨远端静脉输注甘露醇后神经生长因子(NGF)透过血脑脊液屏障(BBB)的变化,并观察外源性NGF对缺氧缺血性脑损伤(HIBD)大鼠脑组织生长相关蛋白-43(GAP-43)表达的影响。方法7日龄新生大鼠100只分为二部分:第一部分随机分为NGF治疗组、模型对照组和假手术组,每组各20只;第二部分随机分为甘露醇加NGF治疗组、单纯NGF治疗组、模型对照组、假手术组,每组各10只。结扎新生大鼠左侧颈总动脉,并吸入氮氧混合气体制作HIBD模型。第一部分NGF治疗组腹腔注射NGF100 U,1次/d。第二部分NGF治疗组腋静脉窦推注NGF 100 U;甘露醇治疗采用腋静脉窦推注200 g/L甘露醇1.5 g/kg。模型制备成功后,取脑组织,制作脑组织切片,HE染色,光镜下观察。用免疫组织化学法检测脑组织GAP-43的表达。迷宫实验检测各组HIBD新生鼠智能的影响。酶联免疫吸附法观察渗透性开放BBB对NGF透过的影响。应用SPSS 11.0软件进行单因素方差分析。结果第一部分腹腔注射NGF后,HIBD新生鼠脑组织GAP-43表达较对照组增高,差异有显著性(P<0.05);迷宫实验其达标次数和正确率较模型对照组有明显改善,差异有显著性(Pa<0.05)。第二部分甘露醇加NGF治疗组脑组织匀浆NGF水平明显高于其他组,差异有显著性(Pa<0.05),单纯NGF治疗组NGF水平明显高于模型对照和假手术组(Pa<0.05)。结论静脉应用甘露醇渗透性开放BBB可显著增加NGF透过大鼠BBB的量;NGF对新生鼠HIBD有保护作用;外源性NGF可增加新生脑组织内GAP-43的表达,并可明显改善HIBD新生鼠的学习记忆能力。

Objective To explore the change of nerve growth factors （NGF） through the blood brain barrier （BBB） after distal intravenous injection of mannitol into the experimental rats and the effect of exogenous NGF on the expression of growth associated protein -43 in hypoxic - ischemic brain. Methods One hundred cases of 7 days rats were divided into 2 units. One unit was divided into 3 groups ： treat- ment group, control group and sham operated group ,20 rats in each group. The other unit was divided into 4 groups ： mannitol and NGF treated group, NGF treated group, control group,and sham operated group, there were 10 rats in each group. The model rats with perinatal hypoxic - ischemic brain damage （ HIBD ） rats were prepared by ligation of left common carotid artery with a temporary systemic hypoxia （ inhaling 80 mL/L O2 and 920 mL/L N2 ）. The sections of brains were processed by immunochemistry with antibodies against GAP-43 ,and the study and memory ability of rats were tested by maze test, The effect of osmotic opening of BBB on the facilitation of NGF＇s passage was tested by ELISA, Results The expression of GAP - 43 increased after NGF treatment, and the differences were remarkable （ P 〈 0. 05 ）, The study and memory ability also were improved after NGF treatment, the difference was remarkable（ Pa 〈0. 05 ）, The content of NGF in brain tissue homogenate of both Mannitol and NGF treated group were higher than other groups , and the differences were remarkable（P 〈 0.05）, Conclusions Osmotic opening BBB by exogenous Mannitol from vein can significantly augment deal of NGF that passed the BBB of rats, NGF can protect rats＇ nerve cell from apomorphosis and necrosis after HIBD. NGF can increase expression of GAP -43 in brain tissue, and HIBD rats＇ study and memory ability can be improved at the same time.