庞伟 周琛 陈艳 李志明 张淑燕

【摘要】目的 探討A型肉毒毒素（BTA）对面部三叉神经痛（TN）大鼠疼痛的改善作用及对炎性介质IL-6、TNF-α表达的影响。方法 从50只大鼠中随机取10只为对照组，剩余大鼠用结扎眶下神经的方法建立TN模型，分为模型组、BTA低剂量组（BTA-L组）、BTA高剂量组（BTA-H组）和卡马西平组，每组各10只。BTA-L组、BTA-H组分别以9、18 μL/kg BTA溶液于手术同侧面部须垫处注射，对照组及模型组给予等量生理盐水，卡马西平组以5 mg/kg卡马西平灌胃。检测大鼠疼痛阈值，ELISA法检测血清中IL-6、TNF-α水平，HE染色观察眶下神经组织病理变化;蛋白免疫印迹法检测三叉神经节中核因子κB（NF-κB）p65、磷酸化型NF-κB p65（p-NF-κB p65）、p38丝裂原活化蛋白激酶（p38MAPK）、磷酸化型p38MAPK（p-p38MAPK）蛋白相对表达量。结果 与对照组比较，模型组注射1、2、3周时疼痛阈值降低（P均 < 0.05）;与模型组比较，BTA-L组、BTA-H组、卡马西平组注射1、2、3周时疼痛阈值升高，且BTA-L组 < BTA-H组 < 卡马西平组（P均 < 0.05）;与对照组比较，模型组血清中IL-6、TNF-α水平及p-NF-κB p65、p-p38MAPK蛋白相对表达量升高（P均< 0.05）;与模型组比较，BTA-L组、BTA-H组、卡马西平组血清中IL-6、TNF-α水平及三叉神经节中p-NF-κB p65、p-p38MAPK蛋白相对表达量降低，且卡马西平组 < BTA-H组 < BTA-L组（P均< 0.05）;HE染色显示，与模型组比较，BTA-L组、BTA-H组、卡马西平组神经纤维肿胀、排列、炎性细胞浸润等异常改变减轻，其中卡马西平组减轻更显著。结论 BTA可降低炎性介质IL-6、TNF-α水平，减轻炎症反应，改善面部疼痛，可能通过抑制NF-κB、p38MAPK信号通路发挥作用。

【关键词】三叉神经痛;A型肉毒毒素;白介素-6;肿瘤坏死因子-α

Effect of botulinum toxin type A on mitigating pain and the expression of serum inflammatory mediators IL-6 and TNF-α in rat models with facial trigeminal neuralgia Pang Wei， Zhou Chen， Chen Yan， Li Zhiming， Zhang Shuyan. Department of Neurology， the Second Affiliated Hospital of Guangdong Medical University， Zhanjiang 524003， China

Corresponding author， Zhou Chen， E-mail： wangzh324@ 126. com

【Abstract】Objective To evaluate the effect of botulinum toxin A （BTA） on mitigating pain and the expression levels of inflammatory mediators interleukin-6 （IL-6） and tumor necrosis factor-α （TNF-α） in rats with facial trigeminal neuralgia （TN）. Methods Ten of the 50 rats were randomly selected into the control group. The infraorbital nerve of the remaining 40 rats was ligated to establish TN models. All TN models were divided into the model group， low-dose BTA （BTA-L） group， high-dose BTA （BTA-H） group and carbamazepine group （n = 10 in each group）. In the BTA-L and BTA-H groups， 9 μL/kg and 18 μl/kg BTA were injected into the facial pad on the same side of the operation. An equivalent amount of normal saline was given in the control and model groups. In the carbamazepine group， 5 mg/kg carbamazepine was given by gastric gavage. The pain threshold was measured. The expression levels of serum IL-6 and TNF-α were detected by enzyme-linked immunosorbent assay （ELISA）. The pathological changes of infraorbital nerve were observed by hematoxylin eosin （HE） staining. The relative expression levels of nuclear factor-κB （NF-κB）p65， phosphorylated NF-κB p65 （p-NF-κB p65）， p38 mitogen-activated protein kinase （p38MAPK） and phosphorylated p38MAPK （p-p38MAPK） proteins in the trigeminal ganglion were quantitatively detected by Western blot. Results Compared with the control group， the pain threshold at 1， 2 and 3 weeks after injection was significantly decreased in the model group （all P < 0.05）. Compared with the model group， the pain threshold at 1， 2 and 3 weeks after injection was significantly increased in the BTA-L， BTA-H and carbamazepine groups， with the highest pain threshold in the carbamazepine group， followed by the BTA-H and BTA-L groups （all P < 0.05）. Compared with the control group， the expression levels of serum IL-6， TNF-α and the relative expression levels of p-NF-κB p65 and p-P38MAPK proteins were significantly up-regulated in the model group （all P < 0.05）. Compared with the model group， the expression levels of serum IL-6， TNF-α and the relative expression levels of p-NF-κB p65 and p-P38MAPK proteins were remarkably down-regulated in the BTA-L， BTA-H and carbamazepine groups， with the highest levels in the BTA-L group， followed by the BTA-H and carbamazepine groups （all P < 0.05）. HE staining showed that compared with the model group， the nerve fiber swelling， arrangement， inflammatory cell infiltration and other abnormal changes were alleviated in the BTA-L， BTA-H and carbamazepine groups， especially in the carbamazepine group. Conclusion BTA can down-regulate the expression levels of serum inflammatory mediators IL-6 and TNF-α， mitigate inflammatory response and ease facial pain probably by inhibiting the NF-κB and p38MAPK signaling pathways.

【Key words】Trigeminal neuralgia; Botulinum toxin type A; Interleukin-6; Tumor necrosis factor-α

面部三叉神经痛（TN）指面部三叉神经部位的突发性疼痛，是常见脑神经疾病，多发于中老年人，且女性群体发病率略高于男性，患者以面部一侧三叉神经分布区阵发性疼痛为主要临床表现[1-2]。TN主要有原发性和继发性两大类，且以原发性疼痛较为常见。临床上TN的治疗方式以药物及手术为主，由于药物会使患者产生晕眩、嗜睡和消化不良等不同程度不良反应，手术方式存在局限性等原因，小部分患者无法应用现有治疗方式进行医治[3-4]。A型肉毒毒素（BTA）是肉毒杆菌在繁殖过程中分泌的生物毒性蛋白，可与胆碱能神经末梢SNAP-25等蛋白产生作用，抑制乙酰胆碱释放，减少肌肉收缩和痉挛[5]。……