成年大鼠局灶脑缺血/再灌注后海马BDNFmRNA和bFGF mRNA的动态变化研究

Study on dynamic changes of BDNF mRNA and bFGF mRNA in hippocampus of adult rats with focal cerebral ischemia/reperfusion

目的观察局灶脑缺血/再灌注大鼠海马脑源性神经营养因子(brain derived neurotrophic factor,BDNF)mRNA和碱性成纤维生长因子(basic fibroblast growth factor,b FGF)mRNA的动态表达。方法将108只雄性Wistar大鼠随机分为正常组(NC组)、假手术组(SC组)、模型组(I/R组),每组再于缺血1h后再灌注于1,3,7,14,21,28d六个时间点进行观察,正常组和假手术组于相应时间点同步观察。采用线栓法制备大鼠右侧大脑中动脉局灶脑缺血/再灌注模型。应用原位杂交法检测大鼠缺血再灌注后1,3,7,14,21,28d缺血侧海马BDNF mRNA和b FGF mRNA表达。结果正常海马区可见少量BDNF mRNA和b FGF mRNA的阳性表达。BDNF mRNA阳性反应主要集中于齿状回颗粒细胞以及CA2、CA3中的锥体细胞胞浆中,b FGF mRNA主要位于海马锥体细胞层、CA1、CA2区。局灶脑缺血/再灌注后,I/R组缺血侧海马BDNF mRNA表达增加,主要见于齿状回颗粒细胞层和锥体细胞层。缺血/再灌注后1d时BDNF mRNA阳性反应即有增多,3d时达到高峰(P<0.01),阳性产物染色较深,7d后迅速下降(P<0.01),28d时接近正常水平。局灶脑缺血/再灌注后,I/R组缺血侧海马可见b FGF mRNA的强阳性表达,1d时开始增加(P<0.05),3d即达一小高峰(P<0.01),7d开始下降,21d时明显下降,28d时降到正常水平(P<0.05)。结论局灶脑缺血/再灌注可上调BDNF mRNA和b FGF mRNA的表达,有利于脑缺血后神经功能恢复,具有神经保护作用。

Objective To study on dynamic changes of BDNF mRNA and b FGF mRNA in hippocampus of adult rats with focal cerebral ischemia / reperfusion. Methods The animal model of focal cerebral ischemia / reperfusion was made by filament occlusion of the right middle cerebral artery. 108 male Wistar rats were randomly divided into three groups: normal control group( NC group),sham operation control group( SC group),ischemia / reperfusion group( I / R group),each group contain 1,3,7,14,21 and 28 d six time points( for each point,n = 6). In situ hybrization method was used to detect the number of BDNF mRNA and b FGF mRNA expression positive cells following various time in hippocampus of adult rats. Results Normally a small amount of BDNF mRNA and b FGF mRNA in hippocampus. After focal cerebral ischemia / reperfusion,the number of BDNF mRNA and b FGF mRNA positive cells increased at each time point,reached small peak value after 3 days( P < 0. 01). Immunoprecipitates were dyed deeply,after 7 days decreased rapidly,28 d decreased to normal level( P <0. 05). Conclusion Focal cerebral ischemia / reperfusion can up-regulated expression of BDNF mRNA and b FGF mRNA,Advantageous to the recovery of neural function after cerebral ischemia and have neuroprotective effect.