姜黄素对大鼠三叉神经痛的镇痛作用

Analgesic effect of curcumin on trigeminal neuralgia in rats

目的评价姜黄素对大鼠三叉神经痛的镇痛作用。方法健康成年雄性SD大鼠30只，体重200～250 g，7～8周龄，采用随机数字表法，将大鼠分为3组（n＝10）：假手术组（S组）、三叉神经痛组（TN组）和三叉神经痛＋姜黄素组（Cur组）。采用眶下神经鞘处注射蛇毒的方法制备三叉神经痛模型。于造模后15 d开始灌胃，Cur组给予姜黄素45 mg/kg，2次/d，连续28 d，TN组给予等容量花生油。分别于造模前（基础状态）和造模后4、7、14、21、28、35、42 d时测定机械痛阈，并观察自由行为学，记录面部修饰行为的时间及次数和探索行为的时间及次数。自由行为学观察结束后，取患侧眶下神经和延髓，透射电镜下观察超微结构。结果与S组比较，TN组造模后4～42 d时机械痛阈降低，面部修饰行为时间延长，面部修饰行为次数增多，探索行为时间缩短，探索行为次数减少（P〈0.05或0.01）；与TN组比较，Cur组造模后28～42 d时机械痛阈升高，面部修饰行为时间缩短，造模后21～42 d时面部修饰行为次数减少，探索行为时间延长，探索行为次数增多（P〈0.05或0.01）。Cur组眶下神经和延髓脱髓鞘改变明显轻于TN组。结论姜黄素45 mg/kg灌胃（2次/d，连续28 d）可减轻大鼠三叉神经痛，其机制与减轻眶下神经和延髓的脱髓鞘改变有关。

ObjectiveTo evaluate the analgesic effect of curcumin on trigeminal neuralgia in rats.MethodsThirty healthy adult male Sprague-Dawley rats, weighing 200-250 g, aged 7-8 weeks, were divided into 3 groups （n=10 each） using a random number table： sham operation group （group S）, trigeminal neuralgia group （group TN） and trigeminal neuralgia ＋ curcumin group （group Cur）. Trigeminal neuralgia model was established by injecting cobra venom solution into the sheath of the infraorbital nerve （ION）. Starting from 15 days after establishment of the model, curcumin 45 mg/kg was intragastrically administered twice a day for 28 consecutive days in group Cur, while the equal volume of peanut oil was administered in group TN.Before establishment of the model （baseline）, and on 4, 7, 14, 21, 28, 35 and 42 days after establishment of the model, the mechanical pain threshold was measured, the free behaviors were observed, and the time and frequency of face-grooming and exploratory behaviors were recorded.After observation of the free behaviors, the ION and medulla oblongata on the affected side were removed for examination of the ultrastructure using transmission electron microscopy.ResultsCompared with group S, the mechanical pain threshold was significantly decreased, the time of face-grooming behaviors was significantly prolonged, the frequency of face-grooming behaviors was significantly increased, the time of exploratory behaviors was significantly shortened, and the frequency of exploratory behaviors was significantly decreased on 4-42 days after establishment of the model in group TN （P〈0.05 or 0.01）. Compared with group TN, the mechanical pain threshold was significantly increased, and the time of face-grooming behaviors was significantly shortened on 28-42 days after establishment of the model, and the frequency of face-grooming behaviors was significantly decreased, the time of exploratory behaviors was significantly prolonged, and the frequency of exploratory behaviors was significantly increased on 21-42 days after establishment of the model in group Cur （P〈0.05 or 0.01）. Microscopic examination revealed that the changes in demyelination of the ION and medulla oblongata were significantly attenuated in group Cur as compared with group TN.ConclusionIntragastrically administered curcumin 45 mg/kg （twice a day for 28 consecutive days） can attenuate trigeminal neuralgia in rats, and the mechanism is related to the attenuated changes in demyelination of the ION and medulla oblongata.