Previous animal studies have demonstrated that the flavonoid small-molecule TrkB agonist, 7, 8-dihydroxyflavone (DHF), promotes axon regeneration in transected peripheral nerves. In the present study, we investigated the combined effects of 7, 8-DHF treatment and bone marrow-derived stem/stromal cells (BMSCs) engraftment into acellular nerve allografts (ANAs) and explore relevant mechanisms that may be involved. Our results show that TrkB and downstream ERK1/2 phosphorylation are increased upon 7, 8-DHF treatment compared to the negative control group. Also, 7, 8-DHF promotes proliferation, survival, and Schwann-like cell differentiation of BMSCs in vitro. While selective ERK1/2 inhibitor U0126 suppressed the effect of upregulation of ERK1/2 phosphorylation and decreased cell proliferation, survival, and Schwann-like cell differentiation partially induced by 7, 8-DHF. In vivo, 7, 8-DHF promotes survival of transplanted BMSCs and upregulates axonal growth and myelination in regenerating ANAs. 7, 8-DHF+BMSCs also improved motor endplate density of target musculature. These benefits were associated with increased motor functional recovery. 7, 8-DHF+BMSCs significantly upregulated TrkB and ERK1/2 phosphorylation expression in regenerating ANA, and increased TrkB expression in the lumbar spinal cord. The mechanism of 7, 8-DHF action may be related to its ability to upregulate TrkB signaling, and downstream activation of survival signaling molecules ERK1/2 in the regenerating ANAs and spinal cord and improved survival of transplanted BMSCs. This study provides novel foundational data connecting the benefits of 7, 8-DHF treatment in neural injury and repair to BMSCs biology and function and demonstrates a potential combination approach for the treatment of injured peripheral nerve via nerve graft transplant.

先前的动物研究表明，类黄酮小分子 TrkB 激动剂 7, 8-二羟基黄酮 (DHF) 可促进横断周围神经的轴突再生。在本研究中，我们研究了 7, 8-DHF 治疗和骨髓源性干/基质细胞 (BMSCs) 植入脱细胞神经同种异体移植物 (ANA) 的联合作用，并探讨了可能涉及的相关机制。我们的结果表明，与阴性对照组相比，TrkB 和下游 ERK1/2 磷酸化在 7, 8-DHF 处理后增加。此外，7, 8-DHF 在体外促进 BMSC 的增殖、存活和雪旺样细胞分化。虽然选择性 ERK1/2 抑制剂 U0126 抑制 ERK1/2 磷酸化上调的作用并降低细胞增殖、存活、和 Schwann 样细胞分化由 7, 8-DHF 部分诱导。在体内，7, 8-DHF 促进移植的 BMSC 的存活，并在再生 ANA 中上调轴突生长和髓鞘形成。7, 8-DHF+BMSCs 还提高了目标肌肉组织的运动终板密度。这些益处与运动功能恢复的增加有关。7、8-DHF+BMSCs显着上调再生ANA中TrkB和ERK1/2的磷酸化表达，并增加腰脊髓中TrkB的表达。7, 8-DHF 作用的机制可能与其上调 TrkB 信号传导的能力，以及再生 ANA 和脊髓中存活信号分子 ERK1/2 的下游激活以及移植 BMSC 的存活率提高有关。这项研究提供了新的基础数据，将 7、