间充质干细胞鞘内移植对脊髓缺血/再灌注损伤大鼠脊髓pERK1/2表达及神经功能的影响

lntrathecal transplantation of mesenchymal stem cell enhances phosphorylation of extracellular signal-regulated kinases 1/2and improves neural function in rats with the spinal cord ischemia/reperfusion injury

目的 探讨间充质干细胞（mesenchymal stem cell,MSC）鞘内移植对脊髓缺血/再灌注损伤大鼠脊髓细胞外调节蛋白激酶（extracellular regulated protein kinases 1/2,ERK1/2）及神经功能的影响.方法 50只SD大鼠制备脊髓缺血/再灌注损伤（spinal cord ischemia/reperfusion injury,SCII）模型,按随机数字表法分为5组（每组10只）：con组,只做SCII;PBS组,SCII后鞘内注射等容量磷酸缓冲液;MSC组,SCII后鞘内注射MSC;U0126＋MSC组,SCII后静脉注射1 ml 1,4-二氨基-2,3-二氰基-1,4-双（邻氨基苯巯基）丁二烯[1,4-diamino-2,3-dicyano-1,4-bis（2-aminophenylthio）-butadiene,U0126]（200μg/kg）,同时鞘内注射MSC;二甲基亚砜（dimethyl sulfoxide,DMSO）＋MSC组,SCII后静脉注射1 ml DMSO,同时鞘内注射MSC.MSC鞘内移植后第2天运用比索比蒂布雷斯纳汉下肢运动功能评分法（Basso,Beattie＆Bresnahan locomotor rating scale,BBB）和下肢体感诱发电位（somatosensory evoked potential,SSEP）监测大鼠脊髓神经功能,采用免疫组织化学方法观察大鼠脊髓磷酸化细胞外信号调节蛋白激酶1/2（phosphorylate extracellular signal-regulated kinases 1/2,pERK1/2）神经元数目,同时采用Western blot技术检测脊髓pERK1/2蛋白含量.结果 鞘内移植MSCs后第2天,与con组比较,MSC组SCII大鼠脊髓pERK1/2神经元数目增加（P〈0.05）,脊髓pERK1/2蛋白含量也增加（P〈0.05）;下肢运动功能评分有所增加（P〈0.05）,SSEP潜伏期缩短（P〈0.05）,波幅增加（P〈0.05）;而用ERK1/2特异性抑制剂U0126阻断ERK1/2磷酸化后,SCII大鼠脊髓神经功能有所改善（P〈0.05）,但是不如MSC组改善明显.结论 MSC鞘内移植可以通过增加脊髓pERK1/2表达,促进SCII大鼠神经功能修复.

Objective To examine the influence of mesenchymal stem cell （MSC） intrathecal transplantation on spinal cord phosphorylate extracellular signal-regulated kinases 1/2 （pERK1/2） expression and neural function in rats with spinal cord ischemia/reperfusion injury （SCII）. Methods Fifty SD rats were subjected to SCII. They were divided into 5 groups （n=10）：① SCII without additional treatment. ② SCII with intrathecal microinjection of PBS. ③ SCI with intrathecal transplantation of MSC in PBS. ④ SCII with intrathecal transplantation of MSCs in PBS＋intravenous injection of U0126 （200 μg/kg） in dimethyl sulfoxide （DMSO）. ⑤ SCII with intrathecal transplantation of MSC and intravenous injection of DMSO. Two days after SCII, neural function was assessed with Basso, Beattie ＆ Bresnahan locomotor rating scale （BBB） and somatosensory potentials evoked by lower limb stimulation. After assessment, pERK1/2 expressions in the spinal cord were assayed with immunohistochemistry and western blot. Results Intrathecal transplantation of MSC elevated the levels of pERK1/2 in the spinal cord, and improved BBB scores, and improved incubation period and amplitude of somatosensory evoked potential （SSEP）. However, ERK1/2 specific inhibitor U0126 blocked ERK1/2 phosphorylation, and attenuated recovery of spinal cord function after intrathecal transplantation of MSC. Conclusions Intrathecal transplantation of MSC may an effective therapeutic strategy to improve recovery of spinal cord function after SCII. pERK1/2 may involve in circuit interaction of MSC with spinal cord.