瑞香素对醋酸、热板及电刺激致痛小鼠的镇痛作用

Anagesic effect of daphnetin in mice with pain due to acetic acid, hot board and electric stimulation

目的:探讨瑞香科植物提取物瑞香素对醋酸、热板测痛仪、电刺激致痛小鼠的镇痛作用。方法:实验于2004-03/07在赣南医学院科研中心实验室完成。①选取昆明种小鼠75只,予以醋酸致痛后随机分为5组,每组各15只,分别为生理盐水组、盐酸吗啡组、瑞香素50mg/kg组、瑞香素25mg/kg组、瑞香素12.5mg/kg组。各组灌胃给药40min后腹腔注射6g/L冰醋酸0.01mL/g,5min后再分别记录各组小鼠10min内的扭体次数。②另选取小鼠75只,随机分为5组,分组同前,采用热板法用GJ-8402型热板测痛仪致痛,准确调节热板温度在(55.0±0.5)℃,并用水银温度计校对。以放入至小鼠舔后足的时间作为痛反应的指标,此时间即为痛阈值,选择痛阈值不超过30s的小鼠。各组腹腔注射给药(药物同前)30min后,测痛阈值。③采用电刺激法观察小鼠80只,随机分为4组,每组20只,生理盐水组、盐酸吗啡组、瑞香素50mg/kg组,瑞香素25mg/kg组。将小鼠固定,用750mL/L乙醇擦去尾部皮脂,待乙醇挥发后,尾部涂一薄层导电胶。用电压3V,连续A脉冲,频率1Hz,波宽为0.04s的方波刺激小鼠尾部,连续3次,每次间隔为5min.连续刺激3次内有2次嘶叫反应者可予采用。给药后15,30,45,60,90min用同样条件重复刺激,凡连续2次不引起嘶叫者,表示药物有镇痛作用,最后分别求各组镇痛抑制率。结果:3种实验275只小鼠均进入结果分析。①扭体反应次数:醋酸致痛后,生理盐水组为(54.28±8.14)次,盐酸吗啡组0次,瑞香素50mg/kg组(8.36±1.63)次,瑞香素25mg/kg组(17.52±4.39)次,瑞香素12.5mg/kg组(30.81±6.76)次,与生理盐水组比较差异显著。②热板测痛仪痛阈反应:生理盐水组痛阈值为(20.41±2.41)s,盐酸吗啡组(42.68±2.47)s,瑞香素50mg/kg组(35.89±2.14)s,瑞香素25mg/kg组(31.67±3.10)s,瑞香素12.5mg/kg组(28.80±3.17)s,与生理盐水组比较差异显著。③对电刺激疼痛的反应率:生理盐水组15,30,45,60,90min镇痛抑制率分别为5%,5%,5%,5%,0,盐酸吗啡组95%,100%,100%,65%,15%,瑞香素50mg/kg组25%,55%,85%,45%,0,瑞香素25mg/kg组15%,30%,35%,20%,0,与生理盐水组比较差异显著。结论:瑞香素具有较明显的镇痛作用,对不同致痛模型显示了对抗作用,同时瑞香素对醋酸诱发的扭体反应,对热板所致疼痛镇痛效果较好,对电刺激引起的疼痛效果稍差,且其镇痛作用以大剂量好,并明显呈剂量依赖关系。

AIM:To study the analgesic effect of daphnetin in the mice with pain due to hot board, acetic acid and elecrtric stimulation. METHODS:The experiment was completed between March to July 2004 at the Center Laboratory of Scientific Research of Gannan Medical College. ①Seventy-five Kunming mice were randomized into five groups with 15 in each group: saline group, morphine group, and daphnetin groups of 50 mg/kg, 25 mg/kg, 12.5 mg/kg. Forty minutes after intragastric administraion, intraperitoneal injection of 6g/L glacial acetic acid (0.01 mL/g) were administrated in all the five groups, and after 5 minutes, times of body torsion within 10 minutes were recorded. ②Another 75 mice were selected and assigned into five groups respectively as well as the above-mentioned grouping.Pain models of mice were made by GJ-8402 hot plate at (55.0±0.5)℃confirmed with a mercurial thermomete. Mice licking their hindfeet as the marker of pain reaction, the time of mice licking their hindfeet was considered as the pain threshold. Mice with the threshold of less than 30 s in each group were enrolled and were injected intraperitomeally with saline, morphine and daphnetin of different dosage, respectively, to record the pain threshold. ③Eighty mice with pain induced by electric stimulation were averagely divided into saline group, morphine group, and daphnetin groups of 20 mg/kg and 50 mg/kg. Mice were fixed to wipe off sebum at the tail with ethanol of 750 mL/L and then spread a thin layer of conductive glue. Square wave at 3 V, 1 Hz, and impulse A was performed to stimulate the tails of mice consecutively for 3 times with an interval of 5 minutes. Mice with twice brays were enrolled. After administration of 15,30,45,60,90 minutes, stimulation under the same condition were repeated. If the mice had no bray in two sequent stimulations, it was shown that the drug had an analgesic effect. Finally, the rate of analgesia was determined in each group. RESULTS: All the 275 mice were involved in the result analysis. ①After acetic acid-induced pain, the times of body torsion were (54.28±8.14)times in the saline group, 0 in the morphine group, (8.36±1.63) times in the 50mg/kg daphnetin group, (17.52±4.39) times in the 25 mg/kg daphnetin group and (30.81±6.76) times in the 12.5 mg/kg daphnetin group. ②Pain threshold determined with hot plate: The pain threshold was (20.41±2.41) s in he saline group, (42.68±2.47)s in the morphine group, (35.89±2.14)s in the 50 mg/kg daphnetin group, (31.67±3.10) s in the 25 mg/kg daphnetin group and (28.80±3.17)s in the 12.5 mg/kg daphnetin group. ③Reaction rate of pain due to electric stimulation: After drug administration of 15,30,45,60,90 minutes, the pain reaction rate was 5%,5%,5%,5%,0 respectively in the saline group, 95%,100%,100%,65%,15%in the morphine group, 25%,55%,85%,45%,0 in the 50 mg/kg daphnetin group and 15%,30%,35%,20%,0 in the 25 mg/kg daphnetin group. CONCLUSION: Daphnetin has a better analgesic effect on the pain due to hot plate and acetic acid except electric stimulation. And the higher the dosage is, the better the effect is, indicating that it shows a dose-effect relation in the analgesia.