脑出血大鼠脑内脑源性神经营养因子蛋白及mRNA表达变化与意义

目的观察脑出血模型大鼠脑内脑源性神经营养因子(BDNF)蛋白和mRNA的分布。方法取健康成年SD大鼠39只,随机分为正常对照组(3只)、假手术组(18只)、模型组(18只)。通过微量注射器向苍白球注入Ⅶ型胶原酶0.4 U建立脑出血模型(模型组),用免疫组织化学方法和原位杂交法分别观察脑出血后2、6 h,1、4、7及14天共6个时间点BDNF蛋白及mRNA的表达变化,以阳性细胞计数作为观察指标。以假手术组、正常对照组作对照。结果脑出血后2 h BDNF蛋白主要表达于血肿周围的小胶质细胞,6 h表达开始增高,1天达高峰,部分表达于神经元,以后逐渐降低,到第7天基本恢复到正常水平,14天后仍可见到少量阳性反应极弱的BDNF阳性细胞;在6 h,1、4天3个时间点上,模型组与正常对照组及假手术组比较差异有显著性(P<0.05);而BDNF mRNA主要表达于神经元,1天后达高峰,7天后两者的表达水平继续下降但仍高于正常,14天后降至基础水平,在6 h,1、4天3个时间点上,模型组与正常对照组及假手术组比较差异有显著性(P<0.01)。结论脑出血后BDNF蛋白及mRNA的表达呈时段性增高。

Expression of brain-derived neurotrophic factor protein and mRNA in rats with cerebral hemorrhage

Objective To observe the distribution of brain-derived neurotrophic factor(BDNF) protein and mRNA in rat brain with cerebral hemorrhage.Methods Forty healthy adult SD rats were divided randomly into normal group(3 rats),sham operated group(18 rats) and model group(18 rats).The intracerebral hemorrhage(ICH) animals were established by microinjection of 0.4 U collagenase Ⅶ into the globus pallidus.The expression variation of BDNF protein and mRNA at 2,6 h and on days 1,4,7 and 14 after cerebral hemorrhage was observed by means of immunohistochemistry and in situ hybridization technique,and the positive cell count served as the observation index.Results BDNF protein was mainly expressed in microglia around the hematoma after ICH,began to be expressed 2 h after cerebral hemorrhage.The expression began to rise at 6 h,peaked after 1 day,decreased to nomal level on the 7th day and slight expression on 14 th day after ICH injury.At 6 h and on days 1 and 4,positive cell counts of the three groups had significant difference(P<0.05).BDNF mRNA was mainly expressed in neurons,reached the peak after first day,then began to decrease 4 days after ICH injury,but still higher than the normal level after 7 days,and came around to the normal expression level 14 days after ICH injury.At 6h,and on days 1 and 4,positive cell counts of the three groups had significant difference(P<0.01).Conclusions The expression of BDNF protein and mRNA increased after ICH.