种植神经损伤中谷氨酸介导的三叉神经节神经元-卫星胶质细胞交互对话机制研究

Sensory impairment caused by neural injury is one of the most common complications associated with dental implant therapy. Recent research has pointed out that the cross-talk between trigeminal ganglion neurons (TGNs) and satellite glial cells (SGCs) was the key mechanism underlying the abnormal sensation in oral and maxillofacial regions. In our previous study, it was found that glutamate (Glu) was the major factor mediating the TGNs-SGCs cross-talk after constrain injury to inferior alveolar nerve. Therefore, in this project, we aim to clarify the effects of Glu-mediated TGNs-SGCs cross-talk in the implant-related nerve injury during the peripheral and central sensitization process of the trigeminal nervous system. This project intends to include following parts: ①Establish the animal models of implant nerve injury to study the characteristics and connection between the injury pathology and neurosensory impairment; ②Clarify the role of TGNs and SGCs in the regulation of Glu level within the trigeminal ganglion after nerve injury; ③Analyze the role of NMDAR, a key Glu receptor, in the TGNs-SGCs cross-talk and extracellular potassium balance underlying the neurosensory impairment after injury; ④Observe the synapse activity changes at the central sensitization level in spinal trigeminal nucleus induced by the peripheral effects above. The findings of this projects will not only reveal the key mechanisms of implant-related neurosensory impairment, but also provide new thoughts for the diagnosis and treatment of such complication associated with implant procedures as well as other dental therapy.

神经损伤引起的感觉功能异常是牙种植的主要并发症之一。本课题组在前期研究基础上，结合相关研究进展提出，谷氨酸（Glu）介导的三叉神经节神经元（TGNs）-卫星胶质细胞（SGCs）交互对话机制，是调控种植神经损伤后感觉功能异常的潜在重要机制。本项目拟围绕上述机制在三叉神经系统外周敏化和中枢敏化过程中的作用，进一步开展以下研究：①建立种植神经损伤动物模型，明确损伤病理改变与感觉功能异常间的关系；②分析TGNs与SGCs调节神经节内Glu的变化特点和机制；③重点研究Glu通过离子型受体NMDAR介导的TGNs-SGCs交互对话，调控胞外钾平衡在感觉功能异常中的外周敏化机制；④在中枢敏化方面，分析上述机制对三叉神经脊束核尾侧亚核（SpVc）突触传递和突触后神经元兴奋性的影响。本项目的实施，可以为种植神经损伤感觉异常的机制和干预研究提供新依据，同时也为口腔医学其他专业中神经并发症的处理提供新的思路。

神经损伤是口腔修复种植临床操作中的严重并发症之一，探索神经损伤后口颌面部感觉功能异常的调控机制是口腔医学和神经科学交叉研究的重要创新方向。本项目重点围绕谷氨酸（Glu）离子型受体NMDAR和AMPAR介导的谷氨酸能信号，研究其介导的三叉神经节（TG）内外周敏化及三叉神经脊束核尾侧亚核（SpVc）内中枢敏化在神经损伤相关的口颌面感觉功能异常中的作用。.下牙槽神经切断（IANX）、慢性压迫性损伤眶下神经（CCI-ION）及TG内直接注射NMDA均可诱发口颌面感觉功能异常。NMDAR亚基NR2A/B敲除后，均能缓解IANX引起的感觉功能异常。IANX后，TG和SpVc中的NR2A、NR2B被激活。由神经元分泌的Glu通过作用于表达在TGNs和SGCs上的NMDAR，通过促进下游细胞及趋化因子和神经营养因子的合成分泌、影响K+、Ca2+及细胞间Glu平衡、促进神经元及胶质细胞活化等途径促进外周敏化及中枢敏化。.NMDAR 亚基NR1、非受体蛋白酪氨酸激酶Src、Pannexin蛋白及α2δ-1均表达于TGNs和SGCs上。TG内注射NMDAR、Src、Panx1或α2δ-1抑制剂能够明显缓解IANX诱导的感觉功能异常。IANX可促进同侧TG中NR1、p-Src、Panx1及α2δ-1上调，同时引起α2δ-1-NR1复合物含量增加。TG内注射NMDAR抑制剂能抑制p-Src、Panx1和α2δ-1；Src抑制剂抑制IANX引起的Panx1增加；Panx1抑制剂及α2δ-1抑制性配体抑制了IANX引起的NR1上调。.CCI-ION术后实验鼠TG内PKC、GluA1和GluA2磷酸化水平及PICK1表达显著升高，同时TG内GluA1膜蛋白升高，但GluA2膜蛋白降低，上述变化可被PKC抑制剂逆转。PICK1与GluA2在TG内的TGNs上共表达，并可相互结合。PICK1抑制剂可减少GluA2磷酸化，并增加GluA2膜蛋白表达水平。以上结果提示，PKC和PICK1协同促进TG中AMPAR的磷酸化，并参与调控膜GluA2向胞内转运，介导了口腔颌面伤害性感觉信号的外周敏化。.本项目研究为种植神经损伤后感觉功能异常的调控机制研究提供新依据，为相关并发症的干预和治疗提供新的思路。对于牙髓根尖周治疗、拔牙、颌面外科手术中的类似神经并发症，本项目研究也有明确的借鉴意义。