局灶性脑缺血大鼠海马区不同部位BDNF的表达及其意义

The expression and its significance of brain-derived neurotrophic factor in different hippocampal subfields after focal cerebral ischemia in rats

目的 研究局灶性脑缺血损伤后海马区不同部位脑源性神经营养因子 (BDNF)表达的规律 ,探讨其对缺血后中枢神经重塑的影响。方法 选取健康成年SD大鼠 40只 ,随机分为脑缺血组和假手术组。采用线栓法建立大脑中动脉脑缺血大鼠模型 ,应用免疫组化技术观察海马各区BDNF的表达。结果 (1 )脑缺血后BDNF的表达水平在海马区具有部位差异性 ,表现为齿状回CA3和CA4 区BDNF的表达明显高于假手术组 ,且差异有显著性 (P <0 0 1 ) ,而CA1 区和CA2 区BDNF表达较假手术组仅轻度升高 ,但差异无显著性 (P >0 0 5) ;(2 )脑缺血组BDNF的表达在脑缺血后 7d时开始升高 ,1 4d时明显增多 ,2 1d时达到高峰 (P <0 0 1 ) ,以后逐渐降低。结论 齿状回、CA3和CA4 区及对缺血损伤具有反应迅速、作用持久的BDNF保护机制对中枢神经系统再生和修复起着重要的作用。

Objective To investigate the regulation of expression of brain derived neurotrophic factor (BDNF) in different hippocampus subfields and explore their effects on neuroplasticity of central nervous system after focal cerebral ischemia.Methods 40 healthy adult SD rats were divided randomly into ischemic group and sham-operated group. Unilateral cerebral ischemia was induced in rats by permanent occlusion of the distal middle cerebral artery. The expression of BDNF was examined by immunohistochemical techniques. Results (1) The expression of BDNF was different in hippocampus subfields after focal cerebral ischemia. It rose significantly in dentate gyrus, CA 3 and CA 4, compared with sham-operated group ( P <0.01), while it rose slightly in CA 1 and CA 2, with no significant difference ( P < 0.05 ). (2) In the ischemic group, the expression of BDNF in hippocampus subfields increased at 7 days, significant increased at 14 days ( P <0.01), attained the peak at 21 days, and decreased in the later days. Conclusions Dentate gyrus, CA 3 and CA 4 showed well BDNF neuron protection mechanism after ischemic injury, played important role in regeneration and repair in central nervous system.