【摘要】 目的采用行为药理学方法,探讨不同时期硬膜外地塞米松治疗对大鼠后足机械刺激疼痛阈值的影响,确定炎症和压迫因素的不同作用。方法取大鼠自体尾部椎间盘组织置于L5神经根下,建立椎间盘突出动物模型,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,观察地塞米松对大鼠后足底机械刺激疼痛阈值的影响。结果早期预防性硬膜外给予地塞米松完全抑制了大鼠2周内机械刺激疼痛阈值的降低,而3周时机械刺激阈值降到最低时治疗性硬膜外给予地塞米松对疼痛则无明显影响。结论椎间盘突出早期阶段,炎性反应是诱致疼痛的主要因素,硬膜外给予地塞米松可以抑制疼痛的产生;当椎间盘突出到达一定阶段,压迫因素成为致痛的主因时,硬膜外再给予地塞米松对已经产生的痛阈降低没有明显的缓解作用。更多还原

【Abstract】 Objective Through the behavioral pharmacology method,this study aimed to explore the contribution of epidural dexamethasone therapy in different stage to the paw withdraw mechanical threshold(PWMT) of the hand paws of the rats on a new sciatic pain model induced by lumbar disc herniation to determine the diferent roles of inflammation and compression.Methods The procedure used autologous disc of the rats from the coccygeal intervertebral discs to impose direct pressure to the L5 dorsal root(DR) to induce an animal model of lumbar disc herniation.After the epidural tube was inserted,early prophylactic therapy and late remedial dexamethasone therapy were conducted to observed the PWMT of both hind paws of the rats.Results Early prophylactic epidural dexamethasone therapy completely suppressed the PWMT of the rats to decrease in 2 weeks,but when the PWMT decreased to the peak in 3 weeks,remedial epidural dexamethasone therapy had no efect on the PWMT.Conclusions The present data suggest that inflammation is the main course of sciatic pain induced by disc herniation in early stage, and prophylactic epidural dexamethasone therapy relieve pain.But in late stage,mechanical compression becomes the main course of sciatic pain,and remedial epidural dexamethasone therapy has no effect on PWMT.更多还原