Khan Junad, Hassun Humza, Zusman Tali, Korczeniewska Olga, Eliav Eli
Eastman Institute for Oral Health, Rochester, NY, 14620, United States.
Department of Diagnostic Sciences, Rutgers School of Dental Medicine, NJ, United States.
Neurosci Lett. 2017 Sep 14;657:106-112. doi: 10.1016/j.neulet.2017.07.049. Epub 2017 Aug 5.
Interleukin-8 (IL-8) is a pro-inflammatory cytokine that has been shown to play a role in inflammatory and autoimmune disorders. The objective of the present study was to assess the levels of IL-8 in rat serum, dorsal root ganglion (DRG) and the sciatic nerve following four different forms of sciatic nerve injury. The models used to induce the injury included partial sciatic ligation (PSL), chronic constriction injury (CCI), perineural inflammation (neuritis) and complete sciatic transection (CST). Mechanical and thermal hyperalgesia were detected by measuring withdrawal responses from a mechanical stimulus and withdrawal latency from thermal stimulation. Enzyme-linked immunosorbent assays (ELISA) was used to assess the IL-8 levels in the affected and contralateral sciatic nerves. Rats exposed to PSL and neuritis developed significant nociceptive response (mechanical and thermal hyperalgesia) in the affected side at three days post-surgery whereas the CCI group at eight days post-surgery. No mechanical or thermal hyperalgesia was observed in rats exposed to CST at either three or eight days postsurgery. Additionally, IL-8 levels were significantly increased in the injured sciatic nerve at 3 and 8days following PSL and neuritis as well as at 8days following CCI when compared to naïve animals. A significant up regulation of IL-8 levels was observed in the ipsilateral DRG at 3 and 8days following CST compared to naïve animals. The serum IL-8 levels remained unchanged in all models of nerve damage. The results of this study suggest that IL-8's role in the neuropathic pain etiology may be specific to nerve injury type.
白细胞介素-8（IL-8）是一种促炎细胞因子，已被证明在炎症和自身免疫性疾病中发挥作用。本研究的目的是评估四种不同形式的坐骨神经损伤后大鼠血清、背根神经节（DRG）和坐骨神经中IL-8的水平。用于诱导损伤的模型包括部分坐骨神经结扎（PSL）、慢性压迫性损伤（CCI）、神经周围炎症（神经炎）和坐骨神经完全横断（CST）。通过测量对机械刺激的退缩反应和对热刺激的退缩潜伏期来检测机械性和热痛觉过敏。采用酶联免疫吸附测定（ELISA）法评估患侧和对侧坐骨神经中的IL-8水平。接受PSL和神经炎处理的大鼠在术后三天患侧出现明显的伤害性反应（机械性和热痛觉过敏），而CCI组在术后八天出现。接受CST处理的大鼠在术后三天和八天都未观察到机械性或热痛觉过敏。此外，与未处理动物相比，PSL和神经炎后3天和8天以及CCI后8天，损伤坐骨神经中的IL-8水平显著升高。与未处理动物相比，CST后3天和8天同侧DRG中IL-8水平显著上调。在所有神经损伤模型中，血清IL-8水平均保持不变。本研究结果表明，IL-8在神经性疼痛病因中的作用可能因神经损伤类型而异。
