The regenerative effects of stem cells derived from dental tissues have been previously investigated. This study assessed the potential of human tooth stem cells from apical papilla (SCAP) on nerve regeneration. The SCAP collected from nine individuals were characterized and polarized by exposure to interferon-γ (IFN-γ). IFN-γ increased kynurenine and interleukin-6 (IL-6) production by SCAP, without affecting the cell viability. IFN-γ-primed SCAP exhibited a decrease of brain-derived neurotrophic factor (BDNF) mRNA levels, followed by an upregulation of glial cell-derived neurotrophic factor mRNA. Ex vivo, the co-culture of SCAP with neurons isolated from the rat dorsal root ganglion induced neurite outgrowth, accompanied by increased BDNF secretion, irrespective of IFN-γ priming. In vivo, the local application of SCAP reduced the mechanical and thermal hypersensitivity in Wistar rats that had been submitted to sciatic chronic constriction injury. The SCAP also reduced the pain scores, according to the evaluation of the Grimace scale, partially restoring the myelin damage and BDNF immunopositivity secondary to nerve lesion. Altogether, our results provide novel evidence about the regenerative effects of human SCAP, indicating their potential to handle nerve injury-related complications.

中文翻译：

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来自牙尖乳头的干细胞的神经再生潜能

先前已经研究了源自牙齿组织的干细胞的再生作用。本研究评估了来自根尖乳头 (SCAP) 的人类牙齿干细胞对神经再生的潜力。从九个人收集的 SCAP 通过暴露于干扰素-γ (IFN-γ) 来表征和极化。IFN-γ 增加了 SCAP 产生的犬尿氨酸和白细胞介素 6 (IL-6)，而不影响细胞活力。IFN-γ 引发的 SCAP 表现出脑源性神经营养因子 (BDNF) mRNA 水平的降低，随后是神经胶质细胞源性神经营养因子 mRNA 的上调。在体外，SCAP 与从大鼠背根神经节分离的神经元的共培养诱导神经突生长，伴随着 BDNF 分泌增加，而与 IFN-γ 启动无关。体内，SCAP 的局部应用降低了坐骨神经慢性收缩损伤的 Wistar 大鼠的机械和热超敏反应。根据 Grimace 量表的评估，SCAP 还降低了疼痛评分，部分恢复了神经损伤继发的髓鞘损伤和 BDNF 免疫阳性。总之，我们的研究结果提供了关于人类 SCAP 再生效应的新证据，表明它们具有处理神经损伤相关并发症的潜力。