Rho/ROCK/actin信号通路在低频脉冲超声调控三叉神经轴突再髓鞘化过程中作用机制的研究

Trigeminal nerve injury is commonly encountered in the oral and maxillofacial region, while current treatments are not ideal in terms of nerve function recovery. Low-intensity pulsed ultrasound (LIPUS) is a widely used physical therapy and has been reported in the treatment of peripheral nerve injury, but specific mechanisms involved remains unclear. Remyelination of regenerated axon by Schwann cells is the key step in the repair of peripheral nerve and Krox20 is a crucial signal molecule in determining the myelinating behavior of Schwann cells. And Rho/ROCK/actin, an important signaling pathway in the transduction of biomechanical signals, directly modulates myelination process. Previous studies by the applicant have revealed that LIPUS treatment increases the expression of Krox20 by Schwann cells and meanwhile promotes depolymerization and reorganization of the actin cytoskeleton system. Based on the previous results, the present study will verify the effect of LIPUS on never repair in vivo by cutting off the mandibular branch of trigeminal nerves in rats and optimize the parameters of LIPUS in the treatment of nerve injury. We next intend to testify the effect of LIPUS on myelination in the co-culture system of trigeminal-nerve neurons and Schwann cells, and investigate the molecular mechanisms in the effects of LIPUS on myelination, specifically the involvement of Rho/ROCK/actin pathway.

三叉神经损伤是口腔颌面部的常见病，现有手段治疗效果较差。低频脉冲超声（LIPUS）是临床广泛应用的物理治疗手段，在外周神经修复中的应用已有报道，但具体作用机制不明。雪旺细胞对新生轴突的再髓鞘化是外周神经修复的关键步骤， Rho/ROCK/actin是重要的力学信号转导通路，且直接参与调控髓鞘形成。申请人前期研究证实，LIPUS可上调雪旺细胞成髓鞘过程的关键转录因子Krox20并促进F-actin的解聚与重构。在此基础上，本研究首先采用大鼠三叉神经损伤模型观察LIPUS在体内促神经修复的效果，筛选最优加载参数；其次通过建立三叉神经节神经元-雪旺细胞共培养模型，体外验证LIPUS对髓鞘形成的作用，并探究Rho/ROCK/actin信号通路在LIPUS调控髓鞘形成中的作用机制。本研究将优化LIPUS对神经损伤治疗的加载方案，探索其分子机制，为LIPUS在神经损伤治疗中的应用奠定基础。

三叉神经损伤是口腔颌面部常见病，现有手段治疗效果较差。低强度脉冲超声（LIPUS）是临床广泛应用的物理治疗手段，在外周神经修复中的应用已有报道，但具体作用机制不明。雪旺细胞对新生轴突的再髓鞘化是外周神经修复的关键步骤，Rho/ROCK/actin是重要的力学信号转导通路，且直接参与调控髓鞘形成。课题组前期研究发现，LIPUS可上调雪旺细胞成髓鞘过程的关键转录因子Krox20并促进F-actin的解聚与重构。. 在此基础上，本项目从LIPUS对神经修复的调控作用出发，采用大鼠下牙槽神经损伤模型观察LIPUS在体内对神经修复的影响，筛选最佳效应参数，并结合体外雪旺细胞的培养，探究Rho/ROCK /actin信号通路在LIPUS调控雪旺细胞增殖、成髓鞘等生物学行为中的影响及作用机制。项目研究发现，LIPUS可促进下牙槽神经手术断端神经再生并相互吻合、断端远端轴突再髓鞘化，以及支配区感觉功能的恢复，且其作用效果与LIPUS的占空比密切相关，提示高占空比有利于神经损伤修复。在相同能量密度下，80%占空比的LIPUS促神经修复作用最佳。体外实验则证实LIPUS可能通过抑制Rho/ROCK/actin信号通路来调控雪旺细胞形态改变、增殖和成髓鞘表达等生物学行，其具体全面的作用机制仍需进一步探索。. 本研究优化了LIPUS对神经损伤治疗的加载方案，通过探索其分子机制为LIPUS在神经损伤治疗中的应用奠定基础。