Xbp-1基因重组神经干细胞移植对大鼠局灶脑缺血再灌注损伤的影响

Effects of transplantation of X-box-binding protein-1 gene-modified neural stem cells on focal brain ischemia/reperfusion injury in rats

背景:将转染Xbp-1基因的神经干细胞移植至脑损伤病变部位,不但确保了Xbp-1基因的稳定及持续表达发挥抗凋亡的作用,也可促进移植后神经干细胞的存活与分化能力。目的:验证Xbp-1基因对移植大鼠脑缺血损伤处神经干细胞的分布、分化、抗凋亡作用及神经功能恢复的影响。方法:选取成年SD大鼠采用线栓法建立大脑中动脉阻塞模型,并随机分成4组干预:对照组(不作处理)、PBS移植组、神经干细胞移植组、Xbp-1-神经干细胞移植组。于干预后7,14,28d进行NSS评分,并取脑制备组织切片,免疫荧光染色观察神经干细胞在脑内的存活与分布情况。移植后第28天使用TUNEL染色检测缺血区域神经细胞凋亡情况,Western blot检测Bcl-2表达水平。结果与结论:移植后7,14,28d Xbp-1-神经干细胞移植组NSS评分显著低于其他3组(P<0.05);神经干细胞可以成功迁徙到脑缺血区域并成活、分化为成熟神经细胞,Xbp-1基因修饰后的神经干细胞成活、增殖以及分化能力均强于普通神经干细胞(P<0.05);与其他3组比较,Xbp-1-神经干细胞移植组脑缺血区域神经细胞凋亡数量明显减少,Bcl-2水平升高(P<0.05)。证实了Xbp-1基因修饰可以增加神经干细胞存活、迁徙能力,并通过抗内质网应激显著降低移植后大鼠缺血模型的NSS评分,促进其神经功能恢复。

BACKGROUND：Neural stem cells（NSCs） transfected with X-box-binding protein-1（Xbp-1） gene transplantation to the lesion site not only ensures the stability of the Xbp-1 gene,sustains effects of anti-apoptotic role,but also promotes survival and differentiation of NSCs following transplantation.OBJECTIVE：To study the effects of Xbp1 gene on the distribution,differentiation and apoptosis of NSCs transplanted into rat brain ischemic injury site,the anti-apoptosis effect and recovery of nerve function.METHODS：Adult Sprague Dawley rats were selected to establish models of middle cerebral artery occlusion（MCAO）.The rats were randomly assigned to four groups：control group（no treatment）,phosphate buffered saline（PBS） transplantation group,NSCs transplantation group,Xbp-1-NSCs transplantation group.At 7,14 and 28 days following treatment,neurological severity score was scored.Brain tissue was obtained to prepare into sections.Immunofluorescence staining was used to observe survivaland distribution of NSCs in the brain.On day 28 following transplantation,terminal deoxyribonucleotidyl transferase-mediated biotin-16-dUTP nick-end labeling assay was used to determine apoptosis of neural cells in the ischemic region.Western blot assay was utilized to detect Bcl-2 expression levels.RESULTS AND CONCLUSION：At 7,14 and 28 days following transplantation,neurological severity score was significantly lower in the Xbp-1-NSC transplantation group compared with other three groups（P 0.05）.NSCs could successfully migrate to the ischemic regions,survived and differentiated into mature nerve cells.Survival,proliferation and differentiation ability of Xbp-1 gene-modified NSCs was stronger than the common NSCs（P 0.05）.Compared with other three groups,apoptotic number of NSCs in the ischemic regions was significantly reduced,but Bcl-2 levels increased in the Xbp-1-NSCs transplantation group（P 0.05）.These verified that Xbp-1 gene modification can increase NSCs survival and migration ability,obviously decrease neurological severity score in rat models after transplantation by anti-endoplasmic reticulum stress,as well as promote the recovery of neurological function.