脑梗死大鼠经血管内皮生长因子165基因治疗后热休克蛋白70的表达

Heat shock protein70expression in the brain of rats with cerebral infarction after receiving vascular endothelial growth factor165gene therapy

目的观察脑梗死大鼠经血管内皮生长因子(VEGF)165基因治疗后热休克蛋白70(HSP70)的表达。方法将25只大鼠随机均分为以下5组:正常对照组(A组);假大脑中动脉闭塞(MCAO)组(B组);MCAO组;空载质粒对照组(D组);hVEGF165基因治疗组(E组)。建模7 d后采用免疫组化的方法观察各组动物脑组织中的HSP70 的表达。结果(1)在皮质中,A、B两组HSP70均低表达(P>0.05);C、D两组表达均较高(P>0.05),与A、B两组相比有较显著的差异(P<0.01);E组表达最强,与各组相比均有显著差异(P<0.01)。(2)在半暗带中,C、D、E各组HSP70 表达均较高,C、D两组间无显著差异(P>0.05),而E组显著高于C、D组(P<0.01)。(3)在梗死灶内,E 组表达较高,显著高于C、D组(P< 0.01)。结论经hVEGF165基因治疗的脑梗死大鼠HSP70表达显著增高,提示VEGF165基因可诱导HSP70的表达。

Objective To investigate the expression of heat shock protein 70 (HSP70) in the brain of rats with cerebral infarc-tion after the administration of vascular endothelial growth factor 165 (VEGF165) gene therapy, thereby to provide molecular basis for clinical gene therapy of cerebral infarction. Methods Twenty-five Wistar rats were divided equally into 5 groups, namely normal control group, sham-operated control group, middle cerebral artery occlusion group (MACO group), eukaryot-ic expression plasmid group (pUCCAGGS group) and gene therapy group (receiving pUCCAGGS/hVEGF165).Rat models of permanent MACO was established by ligation with nylon suture, and in the latter two groups, pUCCAGGS or pUCCAGGS/ hVEGF165 was directly injected into the infracted area. Seven days after the infarction, the rats were killed to obtain the brain tissues for immunohistochemical detection of HSP70 expression. Results In the rat brain cortex of the normal and sham-oper-ated control group, similar low levels of HSP70 expression were detected (P>0.05), while in the MCAO group and pUCCAGGS group, HSP70 levels were both significantly higher (P<0.01), showing no differences between the latter two groups (P>0.05). Most intense HSP70 expression was detected in the gene therapy group (P<0.01). In the penumbra of the infarct area, MCAO, pUCCAGGS, and gene therapy group all had high expression levels of HSP70, which were comparable in the former two groups (P>0.05), with the highest expression levels occurring in the latter group. Within the infarct area, similar expression pattern was observed (P<0.01). Conclusion The elevated HSP70 expression in response to VEGF165 gene therapy in the rats as observed in this study suggests the potency of VEGF165 gene to induce HSP70 expression.