大鼠脑缺血再灌注损伤模型中BDNFmRNA表达减少

［摘要］目的　制备局灶性脑缺血再灌注损伤大鼠模型，并观察大脑皮质脑源性神经营养因子(BDNF)mRNA表达的变化。方法　雄性SD大鼠，采用线栓法闭塞大脑中动脉2h后进行再灌注3d，制备局灶性脑缺血再灌注损伤模型。采用神经缺失评分观察大鼠的行为学表现，TTC染色检查脑组织梗死情况；HE染色观察大鼠脑组织形态结构；RT-PCR技术检测大鼠大脑皮质BDNF mRNA的表达。结果　假手术组大鼠无神经功能障碍表现；脑组织未见梗死灶；脑组织神经细胞形态规则；与正常组相比，大脑皮质BDNF mRNA的相对表达量未见明显变化。与假手术组相比，局灶性脑缺血再灌注损伤模型大鼠出现神经功能障碍；左侧半球可见梗死灶；梗死侧脑组织形态学观察显示神经细胞大量坏死脱落、胞质呈空泡变性、疏松、胞核浓缩深染；大脑皮质BDNF mRNA表达量明显减少。结论　大脑中动脉闭塞2h后进行再灌注3d可造成脑缺血再灌注损伤，可能与大脑皮质BDNF mRNA的表达减少有关。

［关键词］脑缺血再灌注损伤；脑源性神经营养因子

Decrease of BDNF mRNA expression in cortex of cerebral ischemia-reperfusion injury model rats

［Abstract］Objective To observe brain morphology and brain-derived neurotrophic factor(BDNF)mRNA expression in cortex of cerebral ischemia-reperfusion model rats.Methods Twenty-two male SD rats were randomly divided into three groups，normal group，sham group and model group.Focal cerebral ischemia-reperfusion model was induced for 2h by middle cerebral artery occlusion(MCAO)followed by 3d reperfusion.TTC staining was used to examine brain infarction and HE staining was to examine brain morphology，RT-PCR was used to detect BDNF mRNA expression in the cerebral cortex.Results Rats in sham-operated group showed no brain infarction，no brain morphological changes and no significant difference in cortical BDNF mRNA expression compared with rats in normal group.Compared with rats in sham group，model group rats showed infarct in the left hemisphere，necrosis of large numbers of nerve cells，osteoporosis of cytoplasm and condensed stained nuclei in the left hemisphere.In addition，BDNF mRNA expression in cortex is significantly reduced.Conclusion Middle cerebral artery occlusion(MCAO)for 2h followed by reperfusion for 3d could cause cerebral ischemia-reperfusion injury，which might be related to decreasing expression of BDNF mRNA.(www.xing528.com)

［Key words］cerebral ischemia-reperfusion injury；brain-derived neurotrophic factor

脑血管疾病是危害人类生命和健康的主要疾病之一，缺血性脑血管病约占全部脑血管病患者的80%左右［1］，其中大多由大脑中动脉阻塞引起急性血流障碍，导致突发性局灶性脑功能障碍，出现感觉、运动功能丧失，甚至死亡。目前国际上多采用溶栓治疗［2］以恢复脑组织血流供应，但是再灌注本身有时也可加重组织的功能障碍和结构损伤，即引起脑缺血再灌注损伤。脑源性神经营养因子(brain-derived neurotrophic factor，BDNF)属于神经营养素家族，广泛分布于中枢神经系统中，尤其是大脑皮层和海马区，对神经系统的发生、发育过程起着重要作用，可促进神经细胞的存活、增殖、生长、分化及功能表达，而且对损伤的神经元有保护、预防退变和促进再生的作用，是神经科学研究的“热点”之一。然而脑缺血再灌注损伤时大脑皮质BDNF的表达究竟如何变化还不清楚，因此，本文采用雄性SD大鼠，经大脑中动脉栓塞(MCAO)建立局灶性脑缺血再灌注损伤模型，观察大脑皮质BDNF mRNA表达的变化，为下一步的研究奠定实验基础。