淋巴管内皮细胞来源外泌体促进周围神经损伤后的轴突再生

Lymphatic endothelial cells-derived exosomes promote axonal regeneration following peripheral nerve injury

背景:研究表明淋巴管系统参与调控神经再生进程,外泌体具有细胞间通讯功能及多种生物学特性,由此可见淋巴管系统来源外泌体在周围神经损伤疾病治疗中具有巨大潜力。目的:探讨淋巴管内皮细胞来源外泌体促进周围神经损伤后轴突再生的作用及机制。方法:(1)体外通过EdU细胞增殖实验探究淋巴管内皮细胞来源外泌体对施万细胞增殖能力的影响。(2)24只雄性SD大鼠,随机分为3组(n=8),即假手术组、周围神经损伤组及淋巴管内皮细胞来源外泌体治疗组,假手术组仅显露右侧坐骨神经,其余2组右侧坐骨神经挤压后分别在神经外膜下注射PBS及淋巴管内皮细胞来源外泌体,所有大鼠左侧坐骨神经均未做处理。术后28 d取各组大鼠双侧腓肠肌测量肌肉湿质量比,取右侧坐骨神经,通过苏木精-伊红染色及Masson染色评价坐骨神经组织病理学变化及轴突排列情况,采用免疫荧光染色分析轴突再生情况。结果与结论:(1)与对照组相比,淋巴管内皮细胞来源外泌体显著增强了施万细胞的增殖能力,差异有显著性意义(P<0.05)。(2)术后28 d,淋巴管内皮细胞来源外泌体治疗组肌肉湿质量比显著高于周围神经损伤组,差异有显著性意义(P<0.05);与周围神经损伤组相比,淋巴管内皮细胞来源外泌体治疗组轴突排列更加致密且有序,损伤所致轴突崩解和空泡变性现象较少;与周围神经损伤组相比,淋巴管内皮细胞来源外泌体治疗组NF200及S100β荧光强度显著增高,差异有显著性意义(P<0.05)。结果表明,淋巴管内皮细胞来源外泌体通过促进施万细胞的增殖,提高NF200及S100β的蛋白表达来促进周围神经损伤后轴突再生。

BACKGROUND:The lymphatic system is involved in the regulation of nerve regeneration.Exosomes have intercellular communication functions and various biological characteristics.Exosomes derived from the lymphatic system have great potential in the treatment of peripheral nerve injury diseases.OBJECTIVE:To investigate the role and mechanism of lymphatic endothelial cells-derived exosomes on axonal regeneration after peripheral nerve injury.METHODS:(1)The effect of lymphatic endothelial cells-derived exosomes on the proliferation ability of Schwann cells was detected by EdU cell proliferation assay.(2)Twenty-four male SD rats were randomly divided into three groups with 8 rats in each group,including the sham operation group,peripheral nerve injury group and lymphatic endothelial cells-derived exosomes treatment group.The right sciatic nerves of rat models in the sham operation group were exposed without injury.For the rat models in the peripheral nerve injury group and lymphatic endothelial cells-derived exosomes treatment group,the right sciatic nerves were injected with PBS and lymphatic endothelial cells-derived exosomes under the epineurium of the nerve respectively following sciatic nerve crush.All left sciatic nerves of rats were not treated.The rats in each group were sacrificed 28 days following the operation.The bilateral gastrocnemius muscles were removed to measure the muscle wet-weight ratio.Right sciatic nerves were removed.Histopathological changes and axon arrangement of the sciatic nerve were evaluated by hematoxylin-eosin staining and Masson staining,and axonal regeneration was analyzed by immunofluorescence staining.RESULTS AND CONCLUSION:(1)Compared with the control group,lymphatic endothelial cells-derived exosomes significantly enhanced the proliferation ability of Schwann cells,and the difference was statistically significant(P<0.05).(2)At 28 days following the operation,the wet-weight ratio of muscles was significantly higher in the lymphatic endothelial cells-derived exosomes treatment group than that in the peripheral nerve injury group(P<0.05).Axons in the lymphatic endothelial cells-derived exosomes treatment group were arranged more closely and orderly than those in the peripheral nerve injury group and the axon disintegration and vacuolation caused by injury were less.The NF200 and S100βfluorescence intensities in the lymphatic endothelial cells-derived exosomes treatment group were significantly higher than that in the peripheral nerve injury group,and the difference was statistically significant(P<0.05).Our findings indicated that lymphatic endothelial cells-derived exosomes could enhance the proliferation ability of Schwann cells to promote axonal regeneration following peripheral nerve injury by elevating the protein expression of NF200 and S100β.