Role of inflammation on neuropathic pain in trigeminal nerve

以往的研究认为周围神经周围的炎症反应可能参与了周围神经损伤后神经病理性疼痛的通路机制。在本研究计划中，我们利用CFA与神经的紧密放置，建立了无明显神经损伤的神经炎模型。我们发现损伤反应，如ATF3的表达，主要是在小DRG神经元。然而，我们几乎没有发现痛行为阈值的变化，这表明有髓神经元的损伤可能是痛行为阈值变化的重要因素。我们还检测了TRPA1、TRPV1和TRPM8在三叉神经节神经元中的mRNA表达。下颌神经区TRPA 1 mRNA阳性神经元的比例明显高于三叉神经其他区域，表明TRPA 1在三叉神经口部的支配中起重要作用。

Previous papers suggested that inflammatory responses around peripheral nerve may be involved in the path mechanisms of neuropathic pain after peripheral nerve injury. In this research project, we have developed the neuritis model with no apparent neural injury using the close placement of CFA to the nerve. We found the injury responses such as expression of ATF3 were observed in mainly small DRG neurons. However, we found almost no change in the threshold in pain behaviors, suggesting that the damage in myelinated neurons might be important factor for the changes in threshold of pain behaviors. We also examined the mRNA expression of TRPA1, TRPV1 and TRPM8 in trigeminal ganglion neurons. The percentage of TRPA1 mRNA expressing neurons in mandibular nerve region was significantly higher than that in other trigeminal nerve regions, indicating an important role of TRPA1 in the trigeminal nerve innervating mouth region.