目的观察鞘内注射碳酸酐酶抑制剂乙酰唑胺(ACT)对大鼠切口痛行为的影响。方法所有大鼠术前6天鞘内置管,随机分为5组:假手术组、假手术+ACT组、切口痛组、切口痛+ACT低剂量(2.25μg)组、切口痛+ACT高剂量(22.5μg)组,每组16只。按照Brennan法建立切口痛模型。ACT和生理盐水均在术后d 1鞘内给予。分别于术前d1(基础值)、术后d 1(给药前,给药后30、75、120、165、240min)测定大鼠的热缩足潜伏期(TWL)和机械缩足反射阈值(MWT),并予比较。结果切口痛术后d 1(给药前)与基础值相比TWL、MWT均明显降低(P<0.05);鞘内给予高剂量ACT,与给药前相比,给药后30、75、120 min TWL升高(P<0.05),但不影响大鼠的MWT;与切口痛组相比,切口痛+ACT高剂量组在给药后30、75、120 min TWL明显增高(P<0.05)。结论鞘内给予碳酸酐酶抑制剂ACT部分缓解了切口痛大鼠的热痛觉过敏,但是对机械痛觉过敏没有影响,提示碳酸酐酶可能参与了切口痛的热痛敏过程。
Objective To clarify the role of propofol in controlling incisional pain and its potential effects on the spinal opioid receptor expression. Methods A postoperative model of nociception was established in male Sprague-Dawley rats weighing 200-250 g. A total of 96 rats were randomly divided into 8 groups. All drugs were administered intravenously either 5 min pre-operation or 5 min post-operation. The analgesic effects of systemic propofol were demonstrated by the measurement of a cumulative pain score (CPS). After that, the lumbar enlargement of the spinal cord was removed to evaluate the mRNA level of the μ-opioid receptor (MOR) and δ-opioid receptor (DOR) by RT-PCR. Results CPS and DOR mRNA expressions significantly increased after the operation. Both propofol post-treatment and propofol pre-treatment groups showed significant suppression of the increased CPS and the expression of DOR mRNA evoked by pain stimulation. Interestingly, propofol pre-treatment had a more pronounced effect in decreasing CPS and the expression of DOR mRNA. Furthermore, these observations were dose-dependent. MOR mRNA expression significantly increased after operation in all animals and propofol treatment had no impact on it. Conclusion Based on these findings, we suggest that propofol can serve as a valuable adjunct in acute postoperative pain management. Systemic propofol induces an analgesic effect on acute incisional pain in a dose-dependant manner, and this effect is mediated in the spinal cord and may be associated with the spinal DOR.
