氯胺酮预防瑞芬太尼痛觉过敏的实验研究

目的 观察预先皮下注射氯胺酮对瑞芬太尼诱发切口痛模型大鼠痛觉过敏的影响.方法 雄性SD大鼠60只,将大鼠随机分为5组:对照组(C组)、切口痛组(Ⅰ组)、氯胺酮(K组)、瑞芬太尼组(R组)、氯胺酮+瑞芬太尼组(K+R组).Ⅰ组,K组,R组和K+R组行右后足跖肌切口;K组和K+R组术前单次皮下注射氯胺酮0.1 ml(10mg/kg);R组和K+R组切皮开始同时皮下泵注瑞芬太尼0.4 nl(0.04 mg/kg),泵注时间为30 min,所有动物手术和接受微量泵皮下输注均在吸入七氟醚麻醉下进行.于术前24 h、术后2、6、24、48 h检测痛行为学指标,包括机械缩足阈值(paw withdrawal mechanical threshold,PWMT)和热缩足反射潜伏期(paw withdrawal thermal latency,PWTL).结果 与C组和基础值比较,Ⅰ组术后各时间点PWMT和PWTL均降低(P＜0.05);与Ⅰ组相比,R组术后2 h PWMT(6.48±1.23)g和PWTL(11.13±1.95)s即开始降低,此水平持续至术后48h(P<0.05);K+R组术后各时间点PWMT(9.36±1.76,9.41±1.50,10.18±1.42,10.15±1.48)g和PWTL(15.66±2.42,16.24±2.55,15.13±3.07,15.66±2.44)s均高于R组(P＜0.05).结论 术前预先皮下注射氯胺酮可有效预防瑞芬太尼诱发的切口痛模型大鼠痛觉过敏.

Effects of ketamine pretreatment on preventing remifentanil-induced hyperalgesia

Objective To investigate the effects of ketamine on preventing remifentanil- induced hyperalgesia in postoperative pain rat models. Methods Sixty SD rats were randomly divided into 5 groups (n=1 2): control group (C); incisional pain group (Ⅰ); ketamine group (K); remifentanil group (R); ketamine+ remifentanil group (K+R). A right hind paw plantar incision was performed in groups I, K, Rand K+R. Ketamine ( 10 mg/kg 0.1 ml ) was injected subcutaneously 30 min before plantar incision in groups K and K+R.In groups R and K+R, remifentanil (0.04 mg/kg 0.4 ml) were infused subcutaneously with a pump within 30 min at the moment of surgical incision. All rats were anesthetized with sevoflurane. The paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) were used to evaluate the behavioral changes and measured 24 h before incision and 2, 6, 24, 48 after incision. Results Compared with group C and baseline, the decrease of PWMT and PWTL were observed at 2, 6, 24, 48 h after incision in groupI; Compared with group I, the significant decrease of PWMT (6.48±1.23) g and PWTL ( 11.13±1.95 ) s were observed at 2 h after incision in group R, and this level continued until 48 h after incision; Compared with group R, the significant increase of PWMT (9.36±1.76,9.41±1.50, 10.18±1.42, 10.15±1.48) g and PWTL( 15.66±2.42, 16.24±2.55, 15.13±3.07, 15.66±2.44) s were observed at 2,6,24,48 h after incision in group K+R. Conclusion ketamine pretreatment prevents the development remifentanil-induced hyperalgesia in postoperative pain a rat model.