Effects Of Intra-carotid Artery Delivery Of PLXSN-bcl-2cDNA On Cerebral Infarct Volume, Neural Cells Apoptosis And Related Genes Expression Following Focal Cerebral Ischemia In Rats

ObjectiveApoptosis is one of the patterns of cell death during cerebral ischemia, bcl - 2 ( B - cell lymphoma/leukemia - 2 gene) gene family play a major role in the regulation of apoptosis. As an antiapoptotic gene, bcl -2 gene has been proved in many studies that it can protect neural cells from ischemic brain injury. Gene therapy offers great promise for the treatment of cerebral infarction. In our previous studies we have injected plasmid - mediated bcl - 2 cDNA directly into cerebral tissues near the penumbra and intracerebroventricular injection, which showed that bcl - 2 gene can inhibit apoptosis of neural cells effectively during focal cerebral ischemia in rats. However, The traumaty and limitations of diffusion following craniotomy - based brain delivery and intracerebroventricular injection limit these transgenic methods to be applicable to clinic. Trans - vascular delivery of genes to the brain is more convenient, simple, and effective therapeutic method. Our research were to observe the infarct volume, neuronal apoptosis and genes expression of bcl -2,bcl - xl and bax at different time point after intra - carotid artery delivery pLXSN - bcl - 2 cDNA for middle cerebral artery occlusion model in rats. We explore the neuroprotection of bcl - 2 gene during focal cerebral ischemia and provide an experimental proof for clinical treatment of cerebral infarction.Method99 male rats were made into animal models of middle cerebral artery occlusion by Zea - longa suture occlusion method and were randomly divided into three groups: MCAO control group ( n = 33) x plasmid control group ( n = 33 ) and bcl - 2 group ( n = 33 ). plasmid control and bcl - 2 group were respectively intra - carotid administration of pLXSN and pLXSN - bcl - 2 three hours after MCAO. TTC staining to assessment of the infarct volume, TUNEL and immuno-histochemistry methods were adopted respectively to observe the neuronal apop-tosis and the expression of bcl -2xbcl -xl%bax in 24x48^72h after MCAO.Results1. The infarct volume by TTC staining: Compared with MCAO and plasmid control group, the infarct volume of bcl - 2 group was significantly reduced at each time point observed ( P <0. 05 ). There was no significantly difference between MCAO and plasmid control group (P >0. 05).2. The neuronal apoptosis were detectable by TUNEL: Compared with MCAO and plasmid control group, the apoptosis neurons in bcl - 2 group were significantly decreased at each time point ( p <0. 01). There was no distinctively difference between MCAO and plasmid control group (P >0.05).3. bcl -2xbcl - xl and bax protein expression were detectable by immuno-histochemistry:3. 1 The expression of bcl - 2 protein in bcl - 2 group were significantly higher than those in MCAO and plasmid control group at each time point (p <0. 01). There was no significantly difference between MCAO and plasmid control group (P>0.05).3.2 The expression of bcl - xl Protein in bcl - 2 group were significantly higher than those in MCAO and plasmid control group at each time point (p <0. 05). There was no distinctively difference between MCAO and plasmid control group (P>0.05).3.3 The expression of bax Protein in bcl - 2 group were significantly lower than those in MCAO and plasmid control group at each time point (p <0. 05). There was no significantly difference between MCAO and plasmid control group (P>0.05).ConclusionIntra - carotid artery administration of pLXSN - bcl - 2 cDNA into the rats after cerebral ischemia can reduce the infarct volume , attenuate the neuronal ap-optosis. This study indicates that bcl - 2 gene produces neuroprotective effect. One possible mechanism of action was up - regulated antiapoptotic bcl -2Nbcl -xl gene expression and down - regulated proapoptotic bax in the penumbra in the early stage of cerebral ischemia.