胚胎干细胞来源的区域化神经嵴细胞上清修复大鼠坐骨神经损伤的功能特异性研究

The functional specificity of supernatant from cranial and trunk neural crest cells derived from embryonic stem cells in repairing rat sciatic nerve injury

  • 摘要: 背景 周围神经损伤是高发致残性疾病,细胞治疗的免疫排斥和致瘤风险限制了其临床转化,而神经嵴细胞上清的胚胎区域化特性对神经修复的功能特异性影响尚未明确。目的 探究人胚胎干细胞诱导的头颅神经嵴、躯干神经嵴细胞的上清对大鼠坐骨神经损伤的修复作用及功能特异性。方法 通过调整无翅相关整合位点(wingless-related integration site,WNT)通路激活剂浓度及作用时间诱导获得头颅神经嵴与躯干神经嵴细胞,经磁珠分选纯化后,采用定量 Real-Time PCR检测SOX10、P75NTR等神经嵴特异性标志物及HOX家族区域特异性标志物表达水平,免疫荧光染色验证神经嵴细胞身份;构建大鼠坐骨神经离断伤模型,将实验动物随机分为对照组(control,CTRL组)、头颅神经嵴细胞来源上清组(cranial neural crest cells supernatant,CNC-S 组)和躯干神经嵴细胞来源上清组(trunk neural crest cells supernatant,TNC-S 组),每组6 只,分别采用负载基础培养基、头颅神经嵴上清、躯干神经嵴上清的聚己内酯导管桥接修复,术后通过免疫荧光染色检测血管生成(α-SMA、CD31)、轴突延伸(S100-β、NF200)相关指标,透射电子显微镜检测髓鞘厚度、G比率髓鞘生成相关指标,结合组织病理学分析各组修复差异。结果 成功诱导的头颅神经嵴细胞高表达HOXA1、HOXB1 基因,躯干神经嵴细胞高表达HOXA7、HOXB7 基因,二者均稳定表达SOX10、P75NTR的神经嵴标志物(P<0.01);CNC-S组和TNC-S组均能修复大鼠坐骨神经缺损伤,且与CTRL组比较,CNC-S组早期血管生成的α-SMA⁺CD31⁺阳性区域占比升高(P<0.01),TNC-S组轴突再生长度(P<0.01)、髓鞘厚度(P<0.01)均高于CNC-S组和CTRL组,其G比率更接近最佳值0.6,与其余两组比较差异有统计学意义。结论 本研究探究了头颅神经嵴细胞上清与躯干神经嵴细胞上清在坐骨神经缺损伤修复中呈现区域化的功能特异性,CNC-S主导早期血管生成,TNC-S驱动轴突延伸与髓鞘成熟。该发现阐明区域化神经嵴上清的功能分工机制,为周围神经损伤提供精准化、序贯化无细胞修复新策略,为研发分型靶向的神经修复生物制剂提供一定的实验基础。

     

    Abstract: Background Peripheral nerve injury is a highly prevalent disabling disease. The immune rejection and tumorigenic risks of cell therapy limit its clinical translation, while the functional specificity effect of the embryonic regionalization characteristics of neural crest cell supernatant on nerve repair remains unclear. Objective To investigate the reparative effect and functional specificity of the supernatant of cranial neural crest and trunk neural crest cells induced by human embryonic stem cells on sciatic nerve injury in rats. Methods Cranial neural crest and trunk neural crest cells were induced by adjusting the concentration and action time of WNT (wingless-related integration site) pathway activators. After purification via magnetic bead sorting, quantitative Real-Time PCR was adopted to detect the expression levels of neural crest-specific markers (such as SOX10 and P75NTR) and regional-specific markers of the HOX family, and immunofluorescence staining was used to verify the identity of neural crest cells. A rat model of sciatic nerve transection injury was established, and the experimental animals were randomly divided into the control group (CTRL group), cranial neural crest supernatant group (CNC-S group) and trunk neural crest supernatant group (TNC-S group), with 6 rats in each group. Polycaprolactone conduits loaded with basal medium, cranial neural crest supernatant and trunk neural crest supernatant were used for bridging repair respectively. After surgery, immunofluorescence staining was performed to detect indicators related to angiogenesis (α -SMA, CD31) and axon extension (S100- β, NF200); transmission electron microscopy was used to detect myelin formation-related indicators including myelin thickness and G-ratio. The repair differences among groups were analyzed combined with histopathology. Results The successfully induced cranial neural crest cells highly expressed HOXA1 and HOXB1, while trunk neural crest cells highly expressed HOXA7 and HOXB7. Both cell types stably expressed neural crest molecules such as SOX10 and P75NTR (P<0.01). Both the CNC-S group and TNC-S group significantly repaired sciatic nerve defect injury in rats. Compared with the CTRL group, the proportion of α-SMA⁺CD31⁺ positive areas for early angiogenesis in the CNC-S group was significantly increased (P<0.01); the axon regrowth length (P<0.01) and myelin thickness (P<0.01) in the TNC-S group were significantly higher than those in the CNC-S group and CTRL group, and its G-ratio was closer to the optimal value of 0.6, with statistically significant differences compared with the other two groups. Conclusions This study demonstrates that cranial neural crest cell supernatant (CNC-S) and trunk neural crest cell supernatant (TNC-S) exhibit regionalized functional specificity in repairing sciatic nerve defect: CNC-S predominantly promotes early angiogenesis, whereas TNC-S drives axon extension and myelin maturation. These findings elucidate the mechanism underlying the functional division of regionalized neural crest supernatants, provide a novel strategy for precision and sequential cell-free repair of peripheral nerve injury, and lay an experimental foundation for the development of typed and targeted biological agents for nerve repair.

     

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