白细胞介素-8在大鼠腰椎间盘突出模型中的表达及其抑制剂repertaxin的镇痛作用

Interleukin-8 expression in rat lumar disc herniation model and anagesia effect of repertaxin

目的探讨腰椎间盘突出模型大鼠疼痛表现与白细胞介素（IL）-8在脊髓和背根神经节的表达之间的关系以及IL-8抑制剂reper｜axin对疼痛是否具有镇痛作用。方法大鼠平均分为腰椎间盘突出模型组和正常对照组，术后1、5、10、20、30、40、50、60d分别检测模型组和假手术组大鼠的机械痛阀值和热痛闽值；相应的在同1天俭测两组大鼠脊髓以及背根神经节IL-8mRNA的表达。另外，在手术后第10天鞘内注射repertaxin，检测对30min、1、3、5h后对模型大鼠痛阈值的影响。结果大鼠造模同侧脚在手术1d后即产生机械性疼痛，一直持续到60d，而在10d的时候才H1观热辐射痛，直至60d。同时，与止常组比较，模型组大鼠的脊髓和背根神经节IL-8mRNA的表达在60d中均显著上升。存术后10d鞘内注射IL-8受体的抑制剂repertaxin对模型具有显著的镇痛作用。结论IL-8与腰椎间盘突出疼痛密切相关，其抑制剂可以用来治疗此类疼痛。

Objective The purpose of this study is to investigate temporal changes of interleukiin （IL）-8 expression in the spinal eord and dorsal root ganglion and the pain-related behaviors with time course and to elucidate whether repertaxin （IL-8 receptor inhibitor） attenuates pain-related behaviors in a rat model of lumbar disc, herniation. Methods Lmnbar disc herniated rat model was builded. Model rats were divided to model group and control group and tested for mechanical allodynia and thermal hyperalgesia at 2 days before surgery, and on days l, 5, 10, 20, 30, 40, 50 and 60 postoperatively. Experimental group was intratheeally injected with the IL-8 receptor inhibitor at L5 level on postoperative day 10. Me- chanical allodynia of the plantar surface of both hindpaw was tested on 30 nfinutes, 1, 3 and 5 hours after administration. Results Mechanical allodynia in ipsilateral hindpaw developed 1 day after surgery and las- ted until 60 days and thermal withdrawal latency decreased significantly on the left side 10 days after sur- gery and gradually increased through day 60, While IL-8 mRNA expression in spinal dorsal horn and dorsal root ganglion. The IL-8 receptor inhibitor attenuated the mechanical allodynia caused by nucleus pulposus when it was administered on postoperative day 10. Conclusion IL-8 might be a potential therapeutic tar- get in chronic radicular neuropathic pain because of disc herniation, CXCL8 inhibitor could be one of its promising therapeutic agents.