摘要
目的评价鞘内注射吗啡对福尔马林炎性疼痛大鼠脊髓背角环氧化酶-2(COX-2)表达的影响。方法32只鞘内置管成功的雄性SD大鼠,随机分为4组(n=8)：对照组(C组)、模型组(F组)、生理盐水组(NS组)及吗啡组(M组)。鞘内置管后5d,F组、NS组及M组大鼠于左后足掌部皮下注射5％福尔马林50μl,注射福尔马林前30min,NS组鞘内注射20μl生理盐水,M组鞘内注射10μl(10μg)吗啡和10μl生理盐水,C组不给任何处理,采用疼痛加权评分评价疼痛行为学。F组、NS组及M组于注射福尔马林后24 h,C组于鞘内置管后6 d处死大鼠,取L_5脊髓,采用免疫组织化学方法观察脊髓背角COX-2表达。结果吗啡可减轻福尔马林炎性疼痛；与C组比较,F组、NS组脊髓背角COX-2表达增加(P＜0．01)；与F组、NS组比较,M组脊髓背角COX-2表达降低(P＜0．01)。结论鞘内注射吗啡可抑制福尔马林炎性疼痛引起的脊髓中COX-2表达增加,可能与吗啡的抗伤害和镇痛作用有关。
Objective To investigate the effect of intrathecal （IT） morphine on the expression of cyclooxygenase-2 in dorsal horn of spinal cord in a rat model of peripheral pain. Methods Thirty-two male SD rats weighing 240-280g were randomly divided into 4 groups （ n = 8 each） ： group Ⅰ control （C） ; group Ⅱ peripheral pain （PP） ; group m IT-NS ＋ PP and group Ⅳ IT-morphine ＋ PP. Peripheral pain was induced by injection of 5% formalin 50 μl into the plantar surface of left hindpaw in group Ⅱ , m and Ⅳ. A micro-catheter was inserted into subarachnoid space with the tip positioned at lumbar segment of spinal cord under anesthesia with intraperitoneal chloral hydrate in all animals. Normal saline 20 pl （group m ） or morphine 10 μg （group Ⅳ ） was injected intrathecally through the micro-catheter 30 min before intraplantar formalin injection. Pain behavior was assessed using PIS score （ 1 = slight pain, lame while moving with the injected hindpaw touching the floor lightly, 3 - severe pain, flinches and licking of the injected hindpaw） . The animals were killed at 24h after intraplantar formalin injection after assessment of pain behavior. The lumbar segment of spinal cord was removed for determination of COX-2 expression in the dorsal horn of L5 segment of spinal cord by immuno-histochemistry in group Ⅱ , Ⅲ and Ⅳ. In control group the animals were killed at 6 day after intrathecal catheter placement. Results The COX-2 expression in dorsal horn of spinal cord was significantly higher in group Ⅱ and Ⅲthan in group Ⅰ. （control） but was significantly lower in group Ⅳ（intrathecal mouphine） than in group Ⅱ and ⅢP 〈 0.01 ）. Conclusion Intrathecal morphine can inhibit the increase in COX-2 expression in the spinal dorsal horn induced by intraplantar injection of formalin due to its antinociceptive and analgesic effects.
出处
《中华麻醉学杂志》
CAS
CSCD
北大核心
2006年第9期834-837,共4页
Chinese Journal of Anesthesiology
