摘要:
Objective To investigate the effect of bilateral cervical vagotomy on microglial activation in spinal cord in a rat model of persistent postoperative pain evoked by skin/muscle incision and retraction (SMIR).Methods Thirty six male Sprague-Dawley rats were randomly divided into three groups (n =12 each group):group sham operation,group SMIR,and group SMIR + bilateral cervical vagotomy (SV).The rat model of persistent postoperative pain evoked by SMIR was established according to the method described by Flatter.Pain behavior was assessed by paw mechanical withdrawalthreshold (MWT) to yon Frey filament stimulation at 1,3,and 5 days after operation.Four animals were sacrificed at each time point in each group to detect the expression of Iba-I (a specific marker of microglia) in the spinal dorsal horn with immunofluorescence and the microglia was counted.Results MWT was significantly decreased atT1-5 in SMIR and SV (10.3 ±0.6,9.7 ±0.8,9.6 ±0.5; 8.0 ±0.7,7.7 ±0.4,7.6 ± 0.3),while the expression of Iba-1 and microglia counts in the spinal dorsal horn were significantly in-creased at T1-5 in SMIR and SV (1428 ± 134,1245 ± 129,and 1001 ± 117 ;8.0 ± 0.7,7.7 ± 0.4,and 7.6 ±0.3; 187 ± 13,164 ± 11,and 142 ± 14;and 241 ±21,230 ±21,and 202 ± 19).In group SV as compared to group SMIR,MWT was significantly decreased at T1-5,while the expression of Iba-1 and microglia counts in the spinal dorsal horn were significantly increased at T1-5.Conclusions Vagus nerve plays an important role in microglial activation in spinal cord in a rat model of persistent postoperative pain evoked by skin/muscle incision and retraction.%目的 探讨胆碱能抗炎通路对大鼠术后持续性痛及脊髓小胶质细胞活化的影响.方法 成年健康雄性SD大鼠36只,按随机数字表法分为三组(n=12).(1)假手术组(S)组;(2)皮肤肌肉切口牵拉组(SMIR);(3)迷走神经切断疼痛模型组(SV).S组分离暴露肌肉和迷走神经,SMIR组及SV组采用皮肤肌肉切口牵拉法建立大鼠术后持续性痛模型,SV组在制备疼痛模型前切断颈部双侧迷走神经.于术后1、3、5d时测定机械缩足反射阈值(MWT),各时点测定完机械缩足反射阈值后,随机选取4只大鼠测定脊髓背角小胶质细胞特异性标记物Iba-1的表达和计数小胶质细胞.结果 SMIR组及SV组术后1、3、5d的MWT各时点值(10.3±0.6,9.7±0.8,9.6±0.5;8.0±0.7,7.7±0.4,7.6±0.3)均低于假手术组(P<0.05);而SV组低于SMIR组(P<0.05);SMIR组与SV组脊髓背角小胶质细胞Iba-1的表达各时点值(1428±134,1345±129,1301±117;1989±127,1747±134,1668±113)、小胶质细胞计数各时点值(187±13,164±11,162±14;241±21,230±21,202±19)均高于假手术组(P<0.05).而SV组高于SMIR组(P<0.05).结论 迷走神经参与了大鼠术后持续性疼痛及脊髓小胶质细胞活化.