电针对大鼠足背炎性痛病灶局部P物质、IL-1β免疫反应性的影响

Effect of Electroacupuncture on Substance P and Interleukin-1β Positive Immunoreaction in the Inflammatory Pain Focus of the Rats’Hindpaw

目的 :研究电针治疗福尔马林所致炎性痛的神经免疫机制。方法 :采用福尔马林试验 ,在大鼠一侧足背皮下注射 5%福尔马林 50 μL制备局部炎性痛病灶 ,应用痛行为学及免疫组织化学方法 ,观察电针胆经“环跳”穴、“阳陵泉”穴 (刺激参数为 1～ 3V ,4～ 1 6Hz,3 0min)对大鼠痛行为反应、炎症反应及足背炎性痛病灶局部组织P物质、IL 1 β免疫反应性的影响。结果 :①电针能显著抑制福尔马林导致的大鼠缩腿、舔爪等自发痛行为反应 (P <0 0 1 ) ;②电针能减轻福尔马林导致的局部炎症反应并显著翻转炎性痛病灶局部表皮、真皮及皮下组织P物质阳性神经纤维和IL 1 β阳性细胞免疫反应性增强现象 (P <0 0 1 )。结论 :SP与IL 1 β参与了福尔马林所致的炎性痛反应过程 ,电针可能通过抑制炎性痛病灶局部感觉神经末梢合成和释放SP及减少免疫细胞向病灶局部游走、合成并释放IL 1 β从而发挥消炎镇痛作用。

Objective:To elucidate the underlying neuroimmunological mechanism of the effect of EA in resisting inflammatory pain. Methods:21 Wistar rats were evenly randomized into control, inflammation and electroacupuncture (EA) groups. Focal inflammation was produced by subcutaneous injection of 5% formalin (50?μL) into the rats' hindpaw. EA (4～16?Hz, 1～3?V) was applied to “Huantiao”( GB 30) and “Yanglingquan” (GB 34) for 30?min. Spontaneous pain related response(flinching and lifting/licking the affected hindpaw), inflammatory reaction, the substance P (SP) and Interleukin (IL) 1β positive immunoreaction (IR) cells of the epidermis, dermis and hypodermis of the focal tissue were observed with behavioral measures and immunohistochemical techniques separately. Results: EA significantly reduced spontaneous pain related responses in focal inflammatory rats( P <0 01). The total number of inflammatory cells (per 100×100?μm 2 section) in EA group was significantly lower than that of inflammation group, suggesting an anti inflammatory effect. The integral optical density values of the SP IR and IL 1β IR positive cells in the focus were significantly higher than those of control group, whereas those of the two types of IR positive cells were considerably lower than those of inflammation group( P <0.01), suggesting that EA may resist inflammation and pain by suppressing the synthesis and release of SP from the focal sensory nerve endings, reducing the migration of immunocytes to the focus and lessening the synthesis and release of IL 1β.Conclusion: SP and IL 1β participate in the process of inflammatory pain induced by formalin, and EA may relieve focal inflammatory pain by reducing SP and IL 1β levels.