鞘内注射吗啡对切口痛大鼠脊髓Fos表达的影响

Effects of intrathecal morphine on expression of Fos in dorsal horn of spinal cord in rat model of incisional pain

目的：动态观察鞘内注射（intrathecal，IT）吗啡对大鼠切口疼痛及脊髓Fos蛋白表达的影响。方珐：雄性SD大鼠96只，分成4组，以累积疼痛评分观察大鼠行为学，以免疫组织化学法测定大鼠脊髓Fos蛋白表达。结果：在术后2h、24h、48h时点，对照组大鼠的累积疼痛评分明显高于假手术组，术前和术后给药组评分较对照组均明显降低（P〈0．01），但两组间差异均无统计学意义（P〉0．05）；术后第72h，各手术组之间差异均无统计学意义（P〉0．05）；术后96h和120h，各组之间差异均无统计学意义（P〉0．05）。在术后2h，对照组大鼠Fos蛋白表达明显增多（P〈0．01），而IT吗啡可明显抑制脊髓背角Fos蛋白表达，尤以术前给药为甚；术后24～120h，各手术组间差异均无统计学意义（P〉0．05）。结论：术前或术后单次IT吗啡，仅在术后早期有镇痛作用并能抑制Fos蛋白表达的增加。

Objective：To observe the effects of intrathecal（IT） morphine on i ncisional pain and expression of c-fos in spinal cord of rats with postoperative pain. Methods： In a rat model of postoperative pain, the cumulative pain scores were used for evaluating pain behaviors. Immunohistochemistry technique was involved in observing the expression of c-fos in slices of spinal cord of rats. Results：In control group,cumulative pain scores were significantly higher than that in sham-operation rats 2 hours, 24 hours and 48 hours after incision and at the same time, compared with that in control group, cumulative pain scores in treatment groups were significantly lower （P 〈 0.01 ）. There was no significant difference among treatment groups administered with drugs either before or after incision （P 〉 0.05）. Seventy-two hours after incision, there was no significant difference in cumulative pain scores among operative groups （ P 〉 0.05）. From 96 hours to 120 hours after incision, there was no significant difference among all groups （ P 〉 0.05 ）. IT morphine given either before or after incision decreased the number of Fos-LI neurons significantly in dorsal horn of spinal cord 2 hours after incision（ P 〈 0.01 ）. IT morphine given before incision decreased the number of Fos-LII neurons more effectively than that after incision. From 24 hours to 120 hours after incision, there was no significant difference among all operative groups （P 〉 0.05 ）. Conclusions：In a rat model of postoperative pain,IT morphine administered either before or after incision provides analgesia and inhibits the Fos protein expression only in early period after incision.