SDH小胶质细胞和DRG卫星胶质细胞中儿茶酚抑素对神经病理性疼痛的作用及其机理研究

Neuropathic pain (NPP) belongs to chronic pain and itself is a kind of disorder affecting human health seriously, which is so far still a difficult problem in our community. P2X4 receptors in spinal dorsal horn (SDH) microglia mediated neuropathic pain, and catestatin (CST), as inflammatory mediators, mediated inflammation. However, thus far, no literature has documented the role of CST in SDH microglia and dorsal root ganglion (DRG) satellite glial cells (SGCs) on neuropathic pain. Thus, we hypothesize that CST may enhance the sensitivity of P2X4 receptor via inflammatory mediators, thereby participating in the pathogenesis of neuropathic pain. In this project, we will carry out in vivo and in vitro experiments, measure pain behavior of rats suffering from sciatic nerve injury (CCI) neuropathic pain model group after treatment with CST in CCI model group and control group. We will also assess the effect of CST siRNA in CCI model group and control group by behavioral method; The content, mRNA and protein expression of CST from rat SDH microglia and DRG satellite glial cells (SGCs) will be detected by molecular biological technique; Moreover, the interaction between CST and P2X4 receptor in SDH and DRG will be studied by using whole cell patch clamp technique. Thus, through this project, we will understand the role of CST in neuropathic pain and its mechanism, as well as the interaction between CST and P2X4 receptor. The study will shed light on exploring a novel target for the prevention and treatment of neuropathic pain.

神经病理性疼痛（NPP）属于慢性疼痛，严重困扰着人类健康，迄今仍是医学界无法解决的难题。脊髓背角（SDH）小胶质细胞P2X4受体介导NPP，而儿茶酚抑素（CST）作为炎症介质介导炎症反应。但国内外尚无SDH小胶质细胞和背根神经节（DRG）卫星胶质细胞中的CST参与NPP的文献报道。我们推测CST可通过炎症介质使P2X4受体敏感性增强而参与NPP的产生。本课题结合在体及离体实验，应用行为学方法观察坐骨神经慢性压迫性损伤（CCI）模型组、CST处理CCI组、CST-siRNA处理CCI组和对照组大鼠的痛行为变化；通过分子生物学和全细胞膜片钳技术研究SDH小胶质细胞和DRG卫星胶质细胞中CST的含量、mRNA和蛋白表达变化，以及SDH和DRG中CST与P2X4受体的相互作用。通过研究，了解CST在NPP中的作用及其机理，以及CST与P2X4受体的相互作用，为NPP的防治探索新靶点。

本项目研究目的是通过整体动物实验与细胞分子实验相结合，探索背根神经节（DRG）卫星胶质细胞（SGCs）和脊髓背角（SDH）小胶质细胞（MG）中儿茶酚抑素（CST）在嘌呤2X4（P2X4）受体介导坐骨神经慢性压迫性损伤（CCI）大鼠神经病理性疼痛中的作用和相关机制。.在整体动物实验中，通过建立CCI神经病理性疼痛大鼠模型，我们观察到CCI组大鼠DRG和脊髓中CST含量明显增加，CCI+CST组大鼠MWT和TWL较CCI组降低，说明CST涉及CCI大鼠神经病理性疼痛；CCI+CST组大鼠DRG中P2X4受体与GFAP以及脊髓中P2X4受体与OX42的共表达均高于CCI组，并且CCI+CST组大鼠DRG和脊髓中P2X4受体、TNF-α、IL-1β和Cx43均高于CCI组，说明CST可诱导胶质细胞活化和P2X4受体表达上调；CST能上调CCI组大鼠p-P38和p-ERK表达，说明P38、ERK信号通路被激活。这些结果说明，CST可通过诱导胶质细胞活化以及p38、ERK信号通路的激活而增强P2X4受体介导大鼠神经病理性疼痛。.通过细胞分子实验，我们观察到ATP+CST组原代培养DRG卫星胶质细胞和脊髓小胶质细胞P2X4受体表达高于ATP组，ATP+CST组胶质细胞中P2X4受体与GFAP/CD11b共表达高于ATP组，以及ATP+CST组胶质细胞上清中TNF-α和IL-1β含量较ATP组增加，表明CST可诱导胶质细胞的活化和P2X4的表达上调；ATP+CST组胶质细胞中p-ERK表达明显高于ATP组，表明ERK信号通路被激活。这些结果表明，CST可增强P2X4受体介导的胶质细胞活化，ERK信号通路可能参与此过程。.总之，本项目确定了DRG卫星胶质细胞和SDH小胶质细胞中CST对P2X4受体介导大鼠CCI神经病理性疼痛的作用及其可能机制，将为神经病理性疼痛的防治提供实验依据和新靶点。