人肝细胞生长因子基因转染治疗脑梗死的实验研究

Liposome-mediated transfer of the HGF gene results in neuroprotection in adult rat brain after cerebral ischemia

目的探讨人肝细胞生长因子(Hepatocyte growth factor,HGF)基因蛋白在缺血半暗带中的表达水平及其治疗脑梗死及人HGF基因对脑梗死后学习记忆功能恢复的机制,为基因治疗缺血性脑血管病及血管性痴呆探索新的途径和方法。方法选择22月龄纯种健康Wistar大鼠60只,随机分为3组:假手术组20只;模型转染质粒组20只;模型转染空质粒组20只。将人HGF基因直接转染至大脑中动脉阻塞(MCAO)大鼠脑缺血半暗带区,利用免疫组化技术测定半暗带区HGF蛋白表达水平,并检测血管内皮细胞CD31的表达,显微镜下血管计数,使用图像分析软件测定梗死体积,利用被动逃避试验测定梗死后学习记忆功能的恢复情况,比较3组大鼠以上各项指标的差异,观察人HGF基因蛋白在缺血半暗带中的表达水平及其对脑梗死的治疗疗效。结果转染质粒组的半暗带区HGF蛋白表达水平和血管计数显著高于转染空质粒组和假手术组(P<0.01),而转染质粒组的梗死面积显著小于转染空质粒组(P<0.01),同时转染质粒组的梗死后学习和记忆功能明显提高(P<0.01)。结论人HGF基因蛋白能够在缺血半暗带区表达,通过增加梗死区的血管数量,明显缩小脑梗死体积,对脑梗死有良好的治疗作用,同时对脑梗死后学习和记忆功能的恢复也有较好作用。

Objective To investigate whether hepatocyte growth factor（HGF） is beneficial to the treatment of cerebral ischemia.Methods HGF was injected intraventricularly mixed with liposome into corona radiata of adult rats after a transient middle cerebral artery occlusion（MCAO）.The expression of HGF gene and vascular proliferation was measured by RT-PCR and immumohistochemical methods.Morris water maze tests and passive avoidance task were used to detect the recovery of learning and memory.Results Expression of HGF protein in the therapy group increased.Compared with the control group,the number of vessels of the therapy group was significantly higher（P〈0.01）,and the infarct volume of therapy group was obviously smaller in the therapy group（P〈0.01）.The escape latency to the hidden platform in Morris water maze was significantly shortened in HGF plasmid group than control groups,indicating that spatial memory of the stressed rats was stronger than that of the control ones.Conclusion HGF plasmid treatment after stroke can stimulate angiogenesis,promote collateral circulation formation and reduce infarct volume,and can improve the ability of learning and memory in rat with cerebral infarction.