大鼠开胸术后慢性疼痛的预测指标

目的观察疼痛时弥散性伤害抑制性控制(DNIC)的动态变化,对术前DNIC、术后急性疼痛能否作为术后慢性胸痛的预测指标进行初步研究。方法术前检测大鼠DNIC,建立开胸术后慢性疼痛模型,分组为空白组(n=10)、假手术组(n=10)、模型组(n=20),连续监测术后1、3、6、9、12、15、18和21 d的机械痛阈、冷痛阈及DNIC。结果模型组大鼠中,11只发展为慢性疼痛组(CPTP组),9只在经历急性疼痛后痛觉恢复正常(non-CPTP组)。与CPTP组比较,non-CPTP组术前DNIC减弱(P0.05),术后6 d切口附近机械痛阈值及冷痛阈值更低(P0.05)。与术前DNIC相比,模型组术后急性疼痛时期(术后3 d)DNIC减弱(P0.05),CPTP组术后21 d DNIC持续减弱(P0.05),而non-CPTP组DNIC恢复正常。结论术前DNIC及术后6 d急性疼痛程度是开胸术后慢性疼痛的两项危险因素;疼痛急性期,个体DNIC减弱,痛觉恢复正常时,个体DNIC水平也渐趋恢复正常。

Predictors of chronic post-thoracotomy pain in rats

Objective A rat model of chronic post-thoracotomy pain is used to study whether acute pain and pre-operative diffused noxious inhibitory controls(DNIC) can predict chronic pain and how DNIC changes when pain maintains.Methods Rats were randomly divided into three groups:naive group,sham group and model group.DNIC was constantly assessed in individual rats,along with each animal's mechanical hyperalgesia and cold allodynia after thoracotomy.Results In model group,the incidence of chronic post-thoracotomy pain was 55%(11 of 20),which was named CPTP group,and the other 9 rats without chronic pain was defined as non-CPTP group.The pre-operative DNIC was significantly weaker in CPTP group with lower mechanical threshold on 6 days after surgery and higher cold sensitivity on 6 days after surgery comparing with non-CPTP group.In the acute pain phase (day 3),DNIC was decreased in both CPTP group and non-CPTP group as compared with pre-operative period.Besides,DNIC was recovered in non-CPTP group while kept impaired in CPTP group on 21 days after surgery.Conclusions Pre-operatively assessed DNIC efficiency and acute post-operative pain intensity were two independent predictors for CPTP.DNIC was decreased both in acute pain and chronic state,while returned to normal when pain sense was normal.