Bcl-xL基因转染对脊髓损伤细胞凋亡的影响

In vivo cell apoptosis in response to Bcl-xL gene transfaction following spinal cord injuries

目的 观察脂质体介导的Bcl-xL基因体内转染对大鼠脊髓损伤后伤区脊髓细胞凋亡和神经功能恢复的影响。 方法 制备大鼠胸段脊髓T8,9压迫损伤模型。 38只大鼠分成三组 :(1)损伤 +pSFFV .Bcl-xL转染组 (实验组 ,15只 ) ;(2 )损伤 +pSFFV .GFP转染组 (对照组 ,15只 ) ;(3)假损伤组 (8只 )。将阳离子脂质体质粒混合后直接注入大鼠损伤脊髓 ,伤后 3d和 7d利用半定量逆转录 -聚合酶链式反应 (RT -PCR)和免疫组化检测Bcl-xL基因体内表达 ;原位末端标记 (TUNEL)法检测细胞凋亡 ;采用开放场地试验BBB评分和斜板试验 ,评价神经功能。 结果脊髓损伤后 3d和 7d损伤局部Bcl -xLmRNA和蛋白较对照组和假损伤组表达明显增多 ;TUNEL结果显示 ,实验组损伤节段细胞凋亡数比对照组明显减少 ,神经功能改善。 结论 脂质体介导Bcl-xL体内转基因治疗可有效转染脊髓的神经细胞 ;外源性Bcl-xL在损伤脊髓的过度表达可减少脊髓不完全性损伤后凋亡引起的神经元死亡和增强神经细胞成活 ,促进神经功能恢复。

Objective To transfer Bcl-xL oncogene in vivo mediated by cationic liposome into rat spinal cord tissue and to investigate its potential effect on cell apoptosis and recovery of neurologic function in a rat spinal cord compression injury model. Methods After confirmation of Bcl-xl oncogene expression of in vitro cultured cells, the model of acute spinal cord injury was made through compressing at the levels of T 8 and T 9. Thirty-eight rats were divided into three groups, ie, sham group, experimental group (pSFFV.Bcl-xL transfaction plus injury) and control group (pSFFV.GFP transfaction plus injury). The expression of Bcl-xL gene at days 3 or 7 after injection was detected by RT-PCR and immunohistochemical staining. The segments of the injured spinal cord were harvested for morphological studies by using terminal deoxynucleotidyl transferase- mediated dUTP nick end labeling (TUNEL) methods. The neurologic function of spinal cord was accessed by open field (BBB score) and platform test. Results Expression of Bcl-xL detected by RT-PCR and immunohistochemical staining in the experimental group was more significantly increased than that of other two groups at days 3 and 7 after injury. The number of TUNEL labeling positive cells of experimental group decreased significantly than that of control group at the same time respectively and the neurologic function improved. Conclusions Transgenic therapy of Bcl-xL mediated by cationic liposome can successfully transfer neuronal cells of spinal cord. Over expression of Bcl-xL gene in the rat spinal cord tissues may potentially enhance neuronal survival after spinal cord injury and improve neurologic function.