VEGF介导PI3K-AKT信号通路在BMSCs移植治疗大鼠脊髓缺血再灌注损伤中的作用

The role of vascular endothelial growth factor-mediated PI3K-AKT signaling pathway in bone marrow stem cell transplantation treatment for spinal cord ischemic reperfusion injury rats

目的探讨骨髓间充质干细胞(BMSCs)肾下腹主动脉移植对大鼠缺血再灌注损伤脊髓血管内皮生长因子(VEGF)介导的下游信号通路磷脂酰肌醇3-激酶/蛋白激酶B(PI3K/AKT)的影响。方法 24只成年雌性大鼠随机分为假手术组、对照组和移植组,每组8只,采用神经行为学(BBB)评分、运动诱发电位(MEP)和皮层体感诱发电位(CSEP)对大鼠进行神经行为学评价和神经电生理检测;RT-PCR、Western blot分析缺血节段脊髓内VEGF、AKT和凋亡相关基因Bax、Bcl-2的表达水平。结果与假手术组比,移植组和对照组大鼠BBB评分在术后0、4、8、14 d均显著降低(P<0.01),MEP、CSEP潜伏期延长(P<0.01)、波幅减小(P<0.01),缺血节段脊髓内AKT、p-AKT、Bax、Bcl-2 mRNA和蛋白表达增加(P<0.01),且移植组VEGF基因和蛋白表达亦增加(P<0.01)。与对照组比较,移植组BBB评分术后4、8、14 d均增高(P<0.01),MEP、CSEP潜伏期缩短(P<0.01)、波幅增加(P<0.01),VEGF、AKT、p-AKT、Bcl-2 mRNA和蛋白表达增加(P<0.01),而Bax mRNA和蛋白表达减少(P<0.01)。结论肾下腹主动脉移植BMSCs通过增加脊髓损伤病灶局部VEGF的表达,进而介导其下游信号通路PI3K/AKT促进脊髓缺血再灌注损伤大鼠后肢功能恢复。

Objective To investigate the effects of the bone marrow mesenchymal stem cells(BMSCs) transplantation via abdominal aorta on VEGF-mediated downstream signaling pathway PI3 K/AKT in rats with spinal cord ischemic reperfusion injury(SCIRI). Methods 24 adult female SD rats were assigned randomly to 3 group of sham operation group, control group and transplantion group(8 rats in each group). The neurological function was assessed with BBB scores. The motor evoked potentials(MEP) and cortical somatosensory evoked potentials(CSEP) were conducted. The RT-PCR and the Western Blot were used to assess the expression of VEGF, AKT, Bax and Bcl-2 in the ischemic segments of spinal cord. Results Compared with the sham group, in the SCIRI rats, the BBB scores were significantly reduced on Day 0, 4, 8 and 14(P<0.01);the latencies and the amplitudes of MEP and CSEP were significantly longer and lower on Day 14(P<0.01);the mRNA and protein levels of AKT, p-AKT, Bax, Bcl-2 and VEGF were significantly increased in the transplanted group(P<0.01). Compared with the control group, the BBB scores were significantly increased on Day 4, 8 and 14(P<0.01);the latency was significantly shorter and the amplitude was significantly higher(P<0.01);the mRNA and protein levels of VEGF, AKT, p-AKT and Bcl-2 were significantly increased(P<0.01);but the mRNA and protein levels of Bax were significantly reduced in the transplanted group(P<0.01). Conclusions BMSCs transplantation via abdominal aorta can promote the expression of VEGF in the injured spinal cord and significantly improve the hind limb function recovery by VEGF-mediated downstream signaling pathways PI3 K/AKT in SCIRI rats.