目的 建立大鼠皮肤肌肉切口牵拉(skin/muscle incision and retraction，SMIR) 术后持续性疼痛模型，研究SMIR术对术后疼痛的影响。方法 雄性SD大鼠36只，采用随机数字表法将大鼠随机分为空白对照组、假手术组和模型组, 每组 12 只。按Flatters法制作SMIR持续性疼痛模型，应用von Frey纤维细丝法和Hargreaves法测定术前及术后第1、3、7、12、22、32 d的机械缩足反射阈值（mechanical withdrawal threshold, MWT）和热缩足潜伏期（thermal withdrawal latency, TWL）；并且每组随机取4只于术后12 d时电镜下观察手术侧隐神经损伤情况。结果 与空白对照组，模型组大鼠 MWT 在术后第1天即出现降低（P=0.015<0.05）；12d 时下降最为显著（P=0.001<0.01），32d 时差异无统计学意义（P=0.772>0.05）；而假手术组与空白对照组比较在各时间点 MWT差异无统计学意义；整个观察时间过程中模型组大鼠 TWL均无明显改变；SMIR 术及假手术后隐神经均未出现髓鞘肿胀或脱髓鞘等神经损伤现象。结论 进一步证实了SMIR模型的稳定性和可重复性，将为研究术后持续性疼痛的机制及治疗措施提供一个新的平台。
Objective To establish a rat model of persistent postoperative pain evoked by skin/muscle incision and retraction (SMIR) and to test its efficacy. Methods Thirty-six male SD rats were randomly divided into three groups (n=12): control group, sham group and model group. SMIR was produced as Flatters described and the threshold with von Frey filament and radiant heat stimulation were measured before operation (baseline) and at 1st, 3rd, 7th, 12th, 22nd and 32nd postoperative day. The structural damages to myelin sheath of saphenous nerve in 4 rats of each group randomly were observed with electron microscope at 12th postoperative day.Results SMIR surgery induced signi?cantly persistent mechanical hypersensitivity to von Frey stimulation of the plantar ipsilateral hindpaw. Compared to the responses of control group rats，the threshold to mechanical stimulistarted to decrease at 1d（P=0.015<0.05）and peaked at 12d（P=0.001<0.01）after operation. There was no significant difference between the SMIR group and control group at 32d after surgery（P=0.772>0.05）.Mechanicalsensitivity ofcontrolgroup and sham group didnotsignificantly change.SMIR did not induce significantheat hyperalgesia. Electron microscopy of saphenous nerve sections did not show demyelination or oedema in the saphenous nerve of the model group or sham group. Conclusion The results ofthe presentstudysuggestthatthe model ofpersistentpostoperative pain evoked by SMIR isstable and repeatable，which may providea new stagefor thestudy on the mechanismsand treatmentofpostoperativepain.
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