BMP-7介导骨髓间充质干细胞对脊髓损伤修复作用的研究

Regeneration of injuried neurons in the spinal cord is limited by the intrinsic properties of neurons and by a postinjury environment inhibitory to nerve repair, which makes SCI more difficult to cure in medicine. The efforts of the treatment by traditional surgical decompression and drug treatment are not significant because the fundamental problem of the failure of neuron recruitment and regeneration quickly. So, to supply and recover the neurons with the ability of regeneration has been the critical questions for the researchers in orthopaedics surgery and neuroscience. The latest studies have shown that the treatment of SCI by transplanting neural stem cells has become the focus direction in this field. Based on above, wistar rats were chosen as SCI model modified with Allen’s method to investigate the committed differentiation of BMSCs to Neural Cells induced by BMP-7 and the repairing function of BMP-7 in SCI, respectively. In this project, the optimization of the differentiation of BMSCs induced by BMP-7 can accumulate fundamental data for curing SCI;The study of the differentiation and repair induced by BMP-7 in SCI microenvironment can provide guidance and advice to cure SCI. So, there is an important academic significance and clinical application value in this project.

脊髓损伤(简称SCI)后患处神经元极难再生且形成不利于自身修复的微环境，使得脊髓损伤的治疗已成为医学界一大难题。传统手术减压和药物抑损的治疗方法因无法解决受损神经元的快速补充与再生修复这一根本性问题而疗效甚微。如何快速地补充神经元细胞以及修复受损神经元细胞的再生能力是骨科和神经科学研究者迫切需要回答的问题。最新研究表明利用神经干细胞移植治疗SCI已成为该领域今后发展的主导方向。基于此，本项目以大鼠脊髓损伤模型为研究对象，以课题组新近发现的BMP-7诱导BMSCs分化为神经性细胞为研究出发点，探索BMP-7在BMSCs中的定向分化潜力及其在脊髓损伤修复中的初步功能。本项目优化BMP-7诱导BMSCs定向分化为神经样细胞将为临床运用BMSCs治疗SCI积累基础数据；探索BMP-7在SCI微环境中的分化与修复功能可为临床应用BMP-7治疗SCI提供指导。因此本项目具有十分重要的理论研究意义和临床

本项目旨在研究BMP-7诱导BMSCs生成神经样细胞进而在脊髓损伤的治疗中发挥作用。通过BMP7体外干预培养的大鼠BMSCs，显微镜下观察干预后形态学变化，免疫组化、免疫荧光及RT-qPCR实验检测干预后细胞中神经元标志物NF200、SYN及胶质细胞标志物GFAP的表达，结果均证实，75 ng/ml BMP-7能够诱导BMSCs向神经细胞分化。建立SD大鼠脊髓损伤模型，设立假手术组、模型组、BDNF组、BMP-7组、BMSCs组及LV-BMP7-BMSCs组，分别于治疗后1 d、3 d、7 d、14 d、21 d、28 d采集损伤部位脊髓组织，BBB评分显示BMP7、BMSC及LV-BMP7-BMSCs治疗时间的延长，大鼠后肢功能逐渐恢复，且LV-BMP7-BMSCs治疗效果优于BMP7及BMSC单独治疗组；免疫组化检测神经元标志物NF200，结果显示BMP7、BMSC及LV-BMP7-BMSCs治疗后NF200均显著高表达，且LV-BMP7-BMSCs组高于BMP7组，检测树突状标记物MAP-2，结果显示BMP7、BMSC及LV-BMP7-BMSCs治疗后MAP2均显著高表达，且LV-BMP7-BMSCs组高于BMP7组，检测星形胶质细胞标志物GFAP，结果显示BMP7、BMSC及LV-BMP7-BMSCs组均为显著升高，且LV-BMP7-BMSCs组低于BMP7组，检测突触标物MOSP及SYN，结果显示BMP7、BMSC及LV-BMP7-BMSCs治疗后MOSP及SYN均显著高表达，且BMP7组高于BMSC及LV-BMP7-BMSCs组；Western blot检测结果显示Mylin、SYN、NF-200蛋白表达量在各组中随着时间的延长显著升高，且BMP-7、BMSC及LV-BMP7-BMSCs组在治疗后21d与对照组无显著差异；RT-qPCR结果与WB结果趋势一致。综上所述：BMP-7体外可诱导大鼠BMSCs分化为神经细胞，且BMP-7及BMSCs对脊髓神经损伤具有修复再生作用，为临床治疗SCI提供了基础研究数据。