关键词: 坐骨神经损伤, 骨髓干细胞, 外泌体, 轴突再生

Abstract: Objective To explore the effect and mechanism of bone marrow mesenchymal stem cell-derived exosomes （BMSC-EXOs） on repair of sciatic nerve injury. Methods The bone marrow mesenchymal stem cells （BMSCs） of Sprague Dawley（SD）rats were extracted and cultured. BMSCs-EXOs were extracted by ultracentrifugation and identified by fluoroscopic electron microscopy, particle size analysis, and western blotting. Culture PC12 cells, divide the PC12 cells into the blank contral group, 30 μg exosomes group, and 60 μg exosomes group. Observe the phagocytic effect of PC12 cells and PC12 cells axon regeneration by immunofluorescence. The expression of cellular neurofilament protein （NF-200） and growth-related protein （GAP-43） were detected by Western blotting. The SD rat sciatic nerve crush injury models were divided into injury group and treating group. The sciatic nerve of each group was observed by immunofluorescent staining. Results BMSC-EXOs were successfully extracted from the supernatant of BMSCs by ultracentrifugation, which conformed to the definition of particle size, fluoroscopic electron microscopic morphology, and Western blotting. The phagocytosis of BMSC-EXOs by PC12 cells was detected by immunofluorescence, and the axon regeneration of PC12 cells was increased. The increase of axon-related protein synthesis was detected by Western blotting, and the effect increased with increasing dose. There were statistically significant differences in axon length and axon-related protein expression in the three groups of PC12 cells（P<0.01）. In the sciatic nerve injury model, histological observation of the injury area was reduced and the nerve was reconnected. Conclusion BMSC-EXOs can play a role in the treatment of sciatic nerve injury by promoting the regeneration of nerve axons.

Key words: sciatic nerve injury, bone marrow stem cells, exosomes, axon regeneration