鞘内注射p38MAPK抑制剂SB203580对大鼠切口疼痛的影响

目的]了解在大鼠切口痛模型中鞘内注射(IT)p38MAPK抑制剂SB203580对切口疼痛的影响.方法]体重250～300g的雄性SD大鼠32只,随机分为4组,每组8只,分别为假手术组、对照组、IT SB203580组和IT 二甲基亚砜(DMSO)组.按Yaksh法施行鞘内置管. 按Brennan法建立切口疼痛模型.分别于术前、术后2 h、 3 h、 6 h 、1d 、2d、3d 、5d以von Frey细丝法(机械性痛觉过敏)、热辐射法(热痛觉过敏)和累积疼痛评分法观察疼痛行为学的变化.结果]与假手术组和术前值比较,对照组大鼠在术后2 h、3 h、6h、1d和2d的von Frey纤毛刺激机械缩足反射阈值(MWT)均明显降低(P＜0.01),累计疼痛评分均明显增加(P＜0.01),在术后2 h、3 h、6h和1d的热刺激缩足潜伏期(TWL)均明显缩短(P＜0.05或P＜0.01);IT DMSO组大鼠在手术后各时间点的MWT、TWL和累计疼痛评分与对照组比较均无明显不同;与对照组和IT DMSO组比较,IT SB203580组大鼠在术后2 h、3 h、6 h和1 d的MWT均明显增加, TWL均明显延长 (P＜0.05或P＜0.01),累计疼痛评分均明显降低(P＜0.05或P＜0.01).结论]在大鼠切口疼痛模型中, p38MAPK在脊髓水平参与了大鼠切口痛的形成和发展.

Effects of Intrathecal Injection of p38MAPK Inhibitor SB203580 on Incisional Pain in a Rat Model

Objective]To investigate the effects of intrathecal(IT)injection of p38 mitogen-activated protein kinase (p38MAPK) inhibitor SB203580 on incisional pain in a rat model. Methods]Thirty-two male SD rats weighing 250~300 g were randomly divided into four groups with 8 animals in each: Sham operation group, control group, IT SB203580 group and IT DMSO group. PE-10 catheter was inserted intrathecally to the lumbar region according to the method of Yaksh. A 1 cm long incision was made in the plantar region of left hindpaw, according to the method of Brennan. Changes of pain behavior were assessed by withdrawal threshold of the hindpaw to von Frey filament stimulation intensity, withdrawal latency of the hindpaw to radiant thermal and a cumulative pain scores before incision as well as 2h, 3h ,6h, 1d, 2d, 3d, 5d after incision. Results] Compared with the pre-incision and sham operation group, mechanical withdrawal threshold (MWT) of the hindpaw to von Frey filament stimulation intensity in the control group was significantly lower than those at 2h, 3h ,6h, 1d, 2d after incision(P<0.01), the cumulative pain scores in control group was significantly higher than those at 2h, 3h ,6h, 1d, 2d after incision(P<0.01), thermal withdrawal latency(TWL) of the hindpaw to radiant thermal decreased significantly at 2h, 3h ,6h, 1d after incision(P<0.05 or P<0.01). As compared with control group and IT DMSO group, MWT in IT SB203580 group increased significantly, TWL prolonged significantly, the cumulative pain scores declined significantly at 2h, 3h ,6h, 1d after incision(P<0.05 or P<0.01). Conclusion]p38MAPK may play an important role in the pathogenesis of incisional pain in a rat model.