脑源性神经营养因子在大鼠脑缺血再灌注损伤过程中基因表达的变化

Regional Brain-derived Neurotrophic Factor mRNA Level Changes Following Trainsient Focal Brain Ischemia and Reperfusion in the Rat

目的 :观察脑缺血再灌注损伤后脑皮层、梗塞区和海马神经元脑源性神经营养因子 (BDNF)水平的变化 ,及与脑病理变化的关联性 ;探讨 BDNF在脑缺血再灌注损伤中的可能作用机理。方法 :线栓法复制大鼠大脑中动脉脑缺血再灌注模型 ,原位核酸分子杂交检测脑不同区域 BDNFm RNA,图象分析间接定量其水平。结果 :1.脑缺血及缺血再灌注均能诱导双侧脑皮层、海马和梗塞区及其对侧相应区神经元 BDNFm RNA水平增高。2 .梗塞区因缺血损伤过重 ,神经元 BDNFm RNA水平增高的幅度小。 3.再灌注后神经元 BDNFm RNA的水平继续升高 ;其变化规律在不同脑区大致相似。 4.神经元 BDNFm RNA基础水平与神经元抗损伤力呈正相关。结论 :脑缺血及缺血再灌注损伤均导致双侧大脑 BD-NFm RNA表达的变化 ,BDNFm RNA水平的提高能增强神经元的抗损伤能力。

Objective: To study the change of brain-derived neurotrophic factor mRNA (BDNFmRNA) in brain and the effect of BDNF on the neurons after focal cerebral ischemia nad reperfusion in the rats.Methods: The level of regional BDNFmRNA was measured in the rat brain using in situ hybridization.Result: 1.Under basal condition, The highest level of BDNFmRNA was found in the dentate gyrus and hippocampal CA3, Siginficantly lower levels of BDNFmRNA were detected in hippocampal CA1 and in necortes. 2. Following 1h or 3h of trainsient focal cerebral ischemia, There is a marded upregulation of BDNFmRNA expression in the bilateral brain. The lower level of BDNFmRNA in the serious ischemia group was found than that in the slight ischemia group, but also there was the lowest level of regional BDNFmRNA in the ischemic focus.3. After the reperfusion, BDNFmRNA expressions in cortex,hippocampus and ischemic focus increased to the maximum at 6h,12h,24h respectively and returned to contral level within 72h.Conclusion: The levels of regional BDNFmRNA showed here positively correlate at least partly with regional depperece in neuronal resistance to ischemia, which is consistent with the hypothesis of a neuroprotective role of BDNF.