血管性痴呆大鼠海马BDNF表达的长时程变化

目的观察血管性痴呆（VD）大鼠海马脑源性神经营养因子（BDNF）表达的长时间动态变化,初步探讨脑源性神经营养因子在血管性痴呆发生与发展中的作用。方法60只大鼠随机分为假手术组、模型7d组、模型15d组、模型1m组、模型2m组和模型4m组,每组10只。免疫组化分析海马组织BDNF的表达情况。结果①与假手术组比较,模型7d组大鼠海马的BDNF表达增多,CA1区BDNF阳性神经元排列密集,着色深,染色清晰;模型组大鼠15d组、1m组、2m组和4m组各时点海马BDNF阳性细胞均比假手术组明显减少,分布稀疏,显色较浅,有的BDNF阳性细胞呈萎缩状,胞体明显缩小。②与假手术组相比,模型7d组BDNF免疫反应阳性神经元数量及总面积增多（P〈0.01）,而模型15d组、1m组、2m组及4m组大鼠的海马BDNF阳性神经元表达明显减少（P〈0.01）。模型大鼠各组间比较,BDNF免疫反应阳性神经元数量及总面积逐渐减少（P〈0.05,P〈0.01）,但模型2m组和4m组差异不显著（P〉0.05）。结论BDNF在VD大鼠脑缺血再灌后早期对海马缺血的神经元起保护作用,后期BDNF的保护作用减弱在血管性痴呆发生和发展过程中起重要的作用。

Long Term Changes of BDNF Expression of Hippocampus in Vascular Dementia Rats

Objective To observe the long-term dynamic changes of brain-derived neutrophic factor（BDNF） expression of hippocampus in vascular dementia（VD） rats and explore the primary role of BDNF in the VD onset and development.Methods VD rat models were established.Sixty rats were randomly divided into the sham-operated group（SO）,7-day VD model group（7dM）,15-day VD model group（15dM）,1-month VD model group（1mM）,2-month VD model group（2mM） and 4-month VD model group（4mM）.There were 10 rats in each group.The expression of BDNF in hippocampus was detected by immnohistochemical staining and assaying.Results ①Compared with SO group,the BDNF expression in hippocampal CA1 area was increased in 7dM group but decreased in the other model groups;the arrangement of the BDNF-positive neurons was intensive and regular,the staining deepened and clear in 7dM group,but the arrangement of the BDNF-positive neurons were sparse and disorganized and the staining shallowed,some of the BDNF positive neurons were shrinked and smaller in the other model groups.②The number and the total area of BDNF positive neurons were more increased in 7dM group（P〈0.01） but more decreased in the other model groups（P〈0.01） than that in SO group.Compared with each other among the model groups,the number and the total area of BDNF positive neurons were gradually decreased from 7dM group to 4mM group and the differences were significant among the model groups each other（P〈0.05,P〈0.01）except for 2mM and 4mM group（P〉0.05）.Conclusion The BDNF expression in hippocampus increased at early stage after cerebral ischemia/reperfusion but decreased at the later stage for a long time,which suggested that a neuroprotective role of BDNF on the hippocampal ischemic neurons was revealed at early stage but weakened at the later stage after cerebral ischemia/reperfusion.