肉毒毒素A对慢性坐骨神经结扎大鼠机械痛敏和热痛敏的影响

The effects of Botulinum toxin type A on mechanical allodynia and heat hyperalgesia induced by chronic constriction injury of the sciatic nerve in rats

目的探讨肉毒毒素A(botulinum toxin type A,BoNT-A)后处理对神经病理性疼痛大鼠疼痛行为学的影响。方法建立SD大鼠右侧慢性坐骨神经结扎模型(chronic con-striction injury of sciatic nerve,CCI)。CCI术后d3始,CCI同侧肢体足底注射BoNT-A7.5、15、30U·kg-1或等容积生理盐水,或对侧肢体足底注射BoNT-A15或30U·kg-1。分别于术前、术后1、3、5、7、14d,测定大鼠的机械缩足反射阈值(MWT)和热缩足潜伏期(TWL)。结果CCI手术同侧足底皮下注射BoNT-A可以增加大鼠的MWT和TWL,对侧应用BoNT-A对MWT和TWL无影响。结论BoNT-A可以通过局部作用减轻CCI手术同侧肢体的机械痛敏和热痛敏。

Aim To investigate the antinociceptive effect of Botulinum toxin type A （BoNT-A） in a rat model of neuropathic pain. Methods BoNT-A （7.5, 1 5 and 3 0 U ·kg^-1 ） or vehicle was administered to ispilateral side plantar surface of the hindpaw of male Sprague-Dawley rats which were prepared by chronic constriction injury of sciatic nerve to produce neuropathic pain, and BoNT-A （ 15 and 30 U·kg^-1 ） was administered into contralateral side in order to determine the drug-induced systemic effect. Mechanical allodynia and heat hyperalgesia were observed at pre-administration,1,3,5,7 and 14 days after drug administration, and were quantified by measuring mechanical withdrawal threshold（MWT） and thermal withdrawal latency（TWL）. Results Administration of BoNT-A evidently increased the cCI rats MWT and TWL, on the contrary, administration of BoNT-A to contralateral side did not show any significant effect on the MWT and TWL. Conclusion Peripherally administration of BoNT-A remarkably suppressed mechanical allodynia and heat hyperalgesia of rats following neuropathic pain.