大鼠脑外伤后蓝斑去甲肾上腺素能神经元变化的研究

Changes of noradrenergic neurons in the rat locus ceruleus after traumatic brain injury

目的观察脑外伤应激对大鼠蓝斑内去甲肾上腺素能(NA)神经元的表达变化的影响。方法健康Wistar大鼠70只,随机分为正常组和脑外伤模型组,用改进的Feeney′s法制作大鼠脑挫裂伤模型。分别于伤后3、6、12、24、48、72h取出其脑干,切片后做多巴胺β羟化酶(DBH,合成NA的一种标志性酶)免疫组化。结果脑挫裂伤后,大鼠出现右侧前后脚偏瘫,BBB评分降低;免疫组化显示,脑外伤后各时段大鼠蓝斑内出现大量深染的DBH阳性神经元,其数量和染色较正常组均显著增加(P<0.01)。结论大鼠脑外伤后蓝斑NA能神经元被激活,DBH表达增加,使NA合成增多,以适应机体内外环境的变化,提示蓝斑产生的NA在脑外伤应激过程中扮演了十分重要的角色。

Objective To investigate the impact of experimental traumatic brain injury on the noradrenergic （ NA ） neurons in locus ceruleus （LC ） so as to explore possible mechanism of the changes of NA neurons. Methods Seventy healthy Wistar rats were randomly divided into 2 groups： group A, norreal group; group B, traumatic brain injury （TBI） group. The animals in group B were subjected to TBI with the modified Feeney＇s method. The brain stem were removed at 3,6,12,24,48,72 h after the injury respectively. Immunohistochemistry （ IHC ） was used to assess the changes of DBH expression which is the key enzyme of noradrenaline synthesis in LC. Results IHC showed ： more dark - stained NA neurons were found in that of brain injury group at different durations,as compared with control group（ P 〈0.01 ）. Conclusions The significant increase of NA neurons in LC of brain injury group suggests that more NA synthesized by the neurons is necessary to meet the demand of the organism under the stress condition, and NA that LC produces plays a very important role in the process of brain injury.