颈内动脉注射pLXSN-Bcl-2cDNA对局灶性脑缺血大鼠脑梗死体积、神经细胞凋亡及其相关基因表达的影响

目的研究经颈内动脉注射质粒PLXSN介导人Bcl-2基因对大鼠局灶性脑缺血后脑梗死体积,神经细胞凋亡及Bcl-2、Bcl-xl和Bax表达的影响。方法健康Wistar雄性大鼠72只,采用线栓法制备大鼠MCAO模型,随机分为空质粒PLXSN对照组和PLXSN-Bcl-2治疗组。再灌注3h后分别经颈内动脉注射质粒PLXSN、PLXSN-Bcl-2。采用TTC染色法检测脑梗死体积,TUNEL法标记凋亡细胞,免疫组织化学法检测Bcl-2、Bcl-xl、Bax蛋白表达。结果MCAO后24、48和72h,脑梗死体积和凋亡神经细胞率治疗组显著小于对照组(P<0.05和P<0.01),治疗组Bcl-2和Bcl-xl蛋白的表达较对照组显著增加(P<0.01和P<0.05),而Bax蛋白表达治疗组较对照组显著减少(P<0.05)。结论颈内动脉注射质粒PLXSN介导Bcl-2基因对脑缺血有脑保护作用。促进bcl-2、bcl-xl表达升高,下调bax蛋白表达,从而抑制神经细胞凋亡,可能为其治疗脑梗死的机制之一。

Effects of intra-carotid artery delivery of pLXSN-Bcl-2 cDNA on cerebral infarct volume, neural cells apoptosis and related genes expression following focal cerebral ischemia in rats

Objective To observe the infarct volume,neuronal apoptosis and related genes expression after cerebral ischemia by intra-carotid artery delivery of pLXSN-Bcl-2 cDNA. Methods 72 male wistar rats were made into MCAO models and randomly assigned into pLSXN control group and Bcl-2 gene treated group. Two groups were respectively intra-carotid delivery of pLXSN and pLXSN-Bcl-2 three hours after MCAO. We studied the infarct volumes,neuronal apoptosis and Bcl-2,Bcl-xl,Bax expression in 24,48 and 72 h after MCAO. Results In 24,48,72 h after MCAO,the infarction volume and neuronal apoptosis in treated group were significantly less than the control group (P <0.05 and P <0.01,respectively). Compare with the control group,the expression of Bcl-2 and Bcl-xl proteins in treated group significantly increased (P <0.01 and P <0.05,respectively),but Bax proteins in treated group significantly decreased (P <0.05). Conclusions This study indicates that bcl-2 gene produces neuroprotective effect by intra-carotid artery injection after MCAO. One possible mechanism of action was up-regulated antiapoptotic bcl-2,bcl-xl gene expression and down-regulated proapoptotic bax in the penumbra in the early stage of cerebral ischemia.