不同时间硬膜外应用吲哚美辛对大鼠机械性痛敏的影响

CONTRIBUTION OF EPIDURAL INDOMETHACIN APPLICATION IN DIFFERENT TIME TO MECHANICAL HYPERAILGESIA IN RATS

摘要:

目的:探讨不同时间硬膜外应用环氧合酶(COX)抑制剂吲哚美辛(Indomethacin)对大鼠后足底机械性痛觉过敏的影响。方法:取大鼠自体尾部椎间盘组织放置在L5神经根下,造成对L5神经根的直接压迫,建立椎间盘突出致神经根性疼痛动物模型;然后硬膜外置管,采用早期预防性给药及晚期治疗性给药方法,观察吲哚美辛对大鼠后足底机械性痛觉过敏的影响。结果:与对照组相比,早期硬膜外给予吲哚美辛可以完全抑制大鼠2周内双侧后足底机械性痛阈的降低;而当术后3周机械性痛阈降到最低时硬膜外给予吲哚美辛对疼痛没有明显的影响。结论:在椎间盘突出的早期阶段,COX在椎间盘源性神经根性疼痛中起着重要作用,硬膜外应用COX抑制剂吲哚美辛可以有效地缓解早期疼痛的发生;当椎间盘突出到一定阶段,压迫因素成为致痛的主因,这时硬膜外再给予吲哚美辛对疼痛没有明显的缓解作用。

Abstract:

Objectives: To explore the contribution of epidural indomethacin application in different time to the paw withdrawal mechanical threshold (PWMT) in rats. Methods: Autologous disc harvested from the coccygeal vertebrae of the rats was applied to the left L5 dorsal root (DR) to develop an animal model of radiculopathy. A fine tube was inserted epidurally and indomethacin was given at different time in order to observe the effects of early prophylactic and late remedial epidural indomethacin in the PWMT of the rats. Results: Compared with control group,early prophylactic indomethacin application almost inhibited the decrease of PWMT of the rats in 2 weeks, which implies that COX may be involved in radiculopathy induced by disc herniation in the early stage. But when the PWMT decreased to the peak at 3 weeks, remedial epidural indomethacin application had no effects on the PWMT. Conclusions: The present data suggest that COX plays an important role in radiculopathy induced by disc herniation in the early stage and prophylactic epidural indomethacin therapy can relieve pain effectively. But at the late stage mechanical compression become the main course of pain and remedial epidural indomethacin therapy has no effects on PWMT.