雪旺细胞来源的外泌体miR-21通过靶向SPRY2促进大鼠坐骨神经损伤后修复的研究

摘要目的：研究高表达miR-21的雪旺细胞（Schwann cells,SC）来源外泌体对坐骨神经损伤（sciatic nerve injury,SNI）的修复作用及机制。方法：分别采用空载慢病毒和高表达miR-21的慢病毒感染SC株,收集SC上清外泌体并进行鉴定。采用神经断端吻合术建立SNI大鼠模型,术后随机分为模型组、SC来源外泌体组和高表达miR-21的SC来源外泌体组（n=10）。其中,SC来源外泌体组和高表达miR-21的SC来源外泌体组分别采用体外收集的外泌体局部注射进行治疗,3周后行为学实验检测神经功能恢复,免疫荧光染色评价SNI后轴突髓鞘再生,RT-qPCR检测血清外泌体miR-21及神经组织中miR-21和SPRY2的表达水平,双荧光素酶报告基因实验体外验证miR-21和SPRY2之间的靶向互作。结果：与模型组相比,其余各组大鼠坐骨神经功能和神经再生情况均出现明显改善,RT-qPCR结果显示血清外泌体及神经组织中miR-21的表达水平显著升高,神经组织中SPRY2的表达水平显著降低,其中高表达miR-21的SC细胞来源外泌体组较SC来源外泌体组变化更显著;双荧光素酶报告基因实验表明miR-21靶向调节SPRY2的表达。结论：高表达miR-21的SC来源外泌体通过靶向SPRY2显著促进SNI后修复。

Exosomal miR-21 derived from Schwann cells promoting the repair of sciatic nerve injury by targeting SPRY2

AbstractObjective： To investigate the effect and potential mechanism of exosomal miR-21 derived from Schwann cell （SC） in the repairment of sciatic nerve injury （SNI）. Method： SC was infected with negative control lentivirus and lentivirus that expression of miR-21, and its exosome was collected and identified respectively. The SNI rat model was established by nerve stump anastomosis. After surgery, the rats were randomly divided into the model group （n=10）, the SC-derived exosome group （n=10） and the SC-derived exosome group （n=10） that high expression of miR-21. The SC-derived exosomes group and SC-derived exosome group that high expression of miR-21 were treated with local injection of exosome collected in vitro. After 3 weeks, the functional recovery was detected by behavioral experiment. The nerve regeneration was evaluated by immunofluorescence staining. RT-qPCR was used to detect the expression of miR-21 in serum exosome and miR-21 and SPRY2 in sciatic nerve. The targeting interaction between miR-21 and SPRY2 was verified by dual-luciferase reporter gene experiment. Result： Compared with the model group, the functional recovery and regeneration of sciatic nerve were significantly improved in the other two groups. The expression of miR-21 was significantly increased, while the expression of SPRY2 was significantly decreased. The improvement in the SC-derived exosome group with high expression of miR-21 were more significantly than those in the SC-derived exosome group. Conclusion： Exosomal miR-21 derived from SC can significantly promote the repair of sciatic nerve injury by targeting SPRY2.