昂丹司琼对大鼠神经病理性疼痛热痛阈的影响

Effect of ondansetron on thermal pain threshold in rats with experimental neuropathic pain

目的研究昂丹司琼全身应用对大鼠坐骨神经病理性疼痛模型痛阈的影响。方法手术制作大鼠慢性坐骨神经压迫损伤(chronic constriction injury,CCI)模型。分三部分实验:①CCI手术前2h单次给药;②术后第7天单次给药;③持续每天单次给药。三部分实验大鼠均采用随机数字表法分为昂丹司琼组(0.5、2、8mg/kg)(n=8)、盐水对照组(n=8)和假手术组(n=8),并均在术后的35d内观察大鼠热痛阈的变化。结果术前2h单次给予昂丹司琼对CCI大鼠痛阈的下降没有影响;术后第7天单次给予昂丹司琼能短时间拮抗CCI大鼠的热痛阈下降;持续每天单次给予昂丹司琼,在所观察的35d内,剂量相关性的拮抗了CCI大鼠的热痛阈下降。结论全身应用昂丹司琼能有效拮抗CCI大鼠模型热痛阈的下降,持续给药比单次给药效果更明显。

Objective To investigate the effect of ondansetron on the development of neuropathic pain in rats following chronic constriction injury （CCI） on sciatic nerve. Methods This research consisted of 3 parts. ①A single bolus of ondansetron was given intraperitoneally 2 h before nerve injury ; ②A single bolus of ondansetron was given intraperitoneally on the 7th day after nerve injury; ③Continuous administration of ondansetron was given daily for 35 d ; In each part, male SD rats were randomly divided into ondansetron group （0.5, 2, 8 mg/kg）, saline group and sham operated group. The paw withdrawal response to thermal stimulation was tested throughout the 35 d following nerve injury. Results Ondansetron administration before nerve injury had no effect on thermal pain threshold in rats of experimental neuropathic pain. ondansetron administration on the 7th day after nerve injury attenuated the descending of thermal pain threshold but did not alter its descending trend in subsequent time period. Daily administration of ondansetron for 35 d attenuated and further delayed the descending of thermal pain threshold significantly in a dose-dependent manner. Conclusion Continuous administration of ondansetron can prevent or at least delay the descending of thermal pain threshold of rats with experimental neuropathic pain after constriction injury.