SLITRK1通过调节杏仁核突触可塑性在慢性神经病理性疼痛负性情绪中的作用及机制研究

Negative emotions like anxiety and depression induced by chronic neuropathic pain seriously impair life and prognosis of the patients. The abnormal internal loop of amygdala may be involved in it but the specific mechanism is still unclear. SLITRK1 is a transmembrane protein that exists in the central nervous system and regulates synaptic plasticity. SLITRK1-deficient mice showed anxiety/depression-like behavior. We previously found that the expression of SLITRK1 in basolateral amygdala (BLA) of mice with chronic neuropathic pain decreased by the downward trend of pain threshold. Besides, wild type mice obviously showed anxiety/depression-like behavior after conditional knockdown of SLITRK1 in BLA. These results suggest that SLITRK1 may be involved in the pathological mechanism of negative emotions secondary to chronic neuropathic pain by regulating synaptic plasticity. We intend to further clarify the relationship between SLITRK1 and negative emotions induced by chronic neuropathic pain and study the effect of SLITRK1 on synaptic plasticity in the internal loop of amygdala by molecular, behavioral and electrophysiological techniques. Over expression of SLITRK1 in amygdala will be conducted to explore whether it can reverse the negative emotions secondary to chronic neuropathic pain. The purpose of this study was to reveal the cellular and molecular mechanisms of negative emotions such as anxiety and depression induced by chronic neuropathic pain.

慢性神经病理性疼痛引起的焦虑、抑郁等负性情绪严重影响患者的生活及预后，杏仁核内部环路异常可能与之密切相关，但具体的中枢机制仍不甚明了。SLITRK1是一种存在于神经系统、具有调节突触可塑性作用的跨膜蛋白，其基因缺陷小鼠出现焦虑或抑郁样行为。我们的前期研究发现:慢性神经病理性疼痛小鼠脑中基底外侧杏仁核（BLA）的SLITRK1表达随疼痛阈值的降低呈递减趋势；敲减正常小鼠BLA的SLITRK1后，焦虑、抑郁倾向明显增加,提示SLITRK1可能通过调节该脑区的突触可塑性参与慢性神经病理性疼痛负性情绪的病理机制。课题组拟进一步应用分子学、行为学和电生理技术明确SLITRK1与慢性神经病理性疼痛负性情绪的关系、研究SLITRK1对杏仁核内部环路突触可塑性的影响并探索过表达小鼠杏仁核中SLITRK1是否可以逆转慢性神经病理性疼痛负性情绪，揭示慢性神经病理性疼痛继发焦虑、抑郁等负性情绪的细胞与分子机制。

慢性神经病理性疼痛引起的焦虑、抑郁等负性情绪严重影响患者的生活及预后，杏仁核脑区是产生、识别和调节情绪的主要脑区，且与疼痛密切相关，但具体的中枢机制仍不甚明了。SLITRK1是一种存在于神经系统、具有调节突触可塑性作用的跨膜蛋白，定位于兴奋性突触，能够诱导神经元树突发生和突触形成，在脑区表达丰富，其基因缺陷小鼠会出现焦虑或抑郁样行为，而该蛋白与慢性神经病理性疼痛及疼痛继发焦虑、抑郁等负性情绪的关系，目前尚未有研究报道。.本研究利用L5脊神经紧结扎模型（SNL）诱发慢性神经神经病理性疼痛的伤害性刺激，并在D28可诱导出稳定的焦虑抑郁样负性情绪水平变化，并且此时杏仁核脑区内SLITRK1蛋白的表达水平有所降低，神经元树突棘数量减少，兴奋性神经递质转运蛋白VGLUT1表达增加，抑制性神经递质转运蛋白VGAT表达无显著差异，且兴奋性突触前蛋白synaptophysin1和突触后蛋白PSD-95 、HOMER1的表达均有所增加，从而造成杏仁核脑区内抑制性和兴奋性神经递质转运蛋白平衡的失调，使突触可塑性受到影响。在体外实验证明了SLITRK1调控神经元轴突生长、诱导树突发生的作用后，将过表达腺相关病毒微量注射于右侧杏仁核脑区，使病毒特异性识别右侧杏仁核脑区兴奋性神经元，并使该类神经元过表达SLITRK1蛋白，发现SLITRK1表达增加后，不仅可对SNL诱导的慢性神经病理性疼痛具有缓解作用，而且可以缓解由慢性神经病理性疼痛诱发的焦虑抑郁样情绪水平变化，此时杏仁核脑区内神经元树突棘数量有所增加，兴奋性神经递质转运蛋白VGLUT1表达降低，且兴奋性突触前蛋白synaptophysin1和突触后蛋白PSD-95 、HOMER1的表达均有所降低，从而缓解了杏仁核脑区内抑制性和兴奋性神经递质转运蛋白平衡的失调，调节神经元突触可塑性变化，这些机制共同参与了SLITRK1通过调节杏仁核突触可塑性在慢性神经病理性疼痛负性情绪中的作用机制，为过表达杏仁核中的 SLITRK1 可能是治疗或缓解临床慢性神经病理性疼痛及其继发的相关负性情绪的潜在新靶点提供相应理论基础和支持。