TRPV4调控卫星细胞活化在CCD大鼠痛觉过敏中的作用及机制研究

Activation of satellite glial cells (SGCs) in dorsal root ganglion (DRG) contributes to the development and maintenance of the neuropathic pain. Transient receptor potential vanilloid subtype 4 (TRPV4) is a calcium-permeable, non-selective cation channel. However, we currently know very little about the role of TRPV4 on the activation of SGCs. TRPV1, which is highly homologous to TRPV4, could activate SGCs through CCL2 and/or P2XR signaling pathways. Our previous studies showed that chronic compression of DRG (CCD) in rats increases the levels of TRPV4 mRNA and protein expression, in addition to an enhancement in the calcium response to hypotonic stimuli and 4α-PDD. Inhibition of SGCs could relieve mechanical hyperagesia after CCD with significant decreased expression of TRPV4. Recent studies suggested that Ca2+ was the transmitter mediating the soma-SGCs communication and gap junctions. Ca2+ was also essential to CCL2 and P2XR signaling pathways. Therefore, we hypothesize that TRPV4 could activate SGCs and mediate soma-SGCs communication through CCL2 and/or P2XR signaling pathways which then contribute to the neuropathic pain after CCD. Thus, in this study, patch-clamp technique, siRNA, western blot, confocal lasers canning, and real-time PCR technique will be used to verify the role of TRPV4 on activation of SGCs and soma-SGCs communication. We also here investigated whether CCL2 and/or P2XR signaling pathways is the mechanism underling TRPV4-induced SGCs activation and mechanical hyperagesia after CCD to further provide new point of view for the neuropathic pain.

背根神经节(DRG)中的卫星细胞（SGCs）激活后参与神经性疼痛。TRPV4对钙离子有高度通透性，但其对SGCs活化的作用尚不明确。TRPV1（TRPV4较高同源性）可通过CCL2通路和P2XR通路激活SGCs。我们的预实验显示，TRPV4在DRG持续受压（CCD）后表达和功能增强，参与机械痛敏，抑制卫星细胞可降低TRPV4的表达，缓解痛敏。由于神经元与胶质细胞之间的双向通讯、缝隙连接通道开放与关闭、CCL2/P2XR信号通路均为钙依赖性，我们提出假说：TRPV4通过CCL2/P2XR通路调控SGCs活化和神经元－SGCs双向通讯，参与CCD后神经性疼痛。我们将建立大鼠CCD模型、神经元细胞-SGCs共培养模型，采用膜片钳、免疫共沉淀、透射电镜等技术，明确TRPV4对SGCs活化和神经元－SGCs双向通讯的调控作用及相关机制，探讨TRPV4对痛觉过敏的影响，为根性神经痛的治疗提供新的思路。