硬膜外腔注射蛇床子素对髓核致痛大鼠DRG环氧合酶2表达的影响

EFFECT OF EPIDURAL OSTHOLE ON CYCLOOXYGENASE-2 EXPRESSION IN DORSAL ROOT GANGLION CELLS OF RATS WITH RADICULAR PAIN FOLLOWING APPLICATION OF NUCLEUS PULPOSUS

目的:检测不同时期硬膜外腔注射蛇床子素对髓核致炎性神经痛大鼠的机械性痛阈及背根神经节环氧合酶2(COX-2)表达的影响,探讨蛇床子素抗炎镇痛的机制。方法:建立髓核致炎性神经痛大鼠模型,术后第6天或第13天硬膜外注射2%蛇床子素50ul,测定大鼠后肢50%机械性撤足阈值(50%PWT)的变化,并用免疫荧光法和Western blot法检测L4-L6背根神经节COX-2的表达。结果:术后第6天硬膜外腔给予蛇床子素可明显提高髓核致痛大鼠的50%机械性撤足阈值,抑制背根神经节COX-2的表达。术后第13天应用蛇床子素对50%PWT只有一过性抑制,对COX-2表达无明显影响。结论:早期硬膜外应用蛇床子素对髓核致炎性神经痛大鼠有明显、持久的镇痛作用,可能与其抑制COX-2表达的程度相关。

Objective ： To explore the effect of epidural Osthole adminstrated in different phases on the mechanic allodynia and expression of cyelooxygenase-2 （COX-2） in dorsal root ganglion （DRG） cells in rat model with radieular pain following application of nucleus pulposus. Methods：2% Osthole 50μ1 was epidural administrated to a lumbar disc herniation model on postoperative day 6 or day 13. 50% Paw withdrawal thresholds （50% PWT） were assessed and L4-5 DRGs were harvested on postoperative day 7 or day 14 for evaluation of expressions of COX-2. Results ： Administration of osthoe on day 6 significantly in- hibited the decrease of 50% PWT and expression of COX-2 （ P 〈 0.05 ） , while the inhibition of 50% PWT was transient and no change in COX-2 levels was observed as osthole was injected on day 13 （P 〉 0.05 ）. Conclusions ： Early epidural administration of osthoe could produce significant and long-acting analgesic effect on rats following application of nucleus pulposus. The great gap of analgesic activities on different injection time might be associated with the inhibitory effect on expression of COX-2 in DRG cells.