A型肉毒毒素对神经病理性疼痛大鼠镇痛作用及作用途径的研究

目的：观察A型肉毒毒素（BTX—A）对L5前根切断（L5 VRT）神经病理性疼痛模型大鼠的镇痛作用并探讨其最佳给药途径。方法：雄性SD大鼠108只，随机分为3组（n=36），皮下注射给药组、坐骨神经表面给药组、坐骨神经注射给药组，制备L5 VRT模型，各组又分为术后4d给药组、术后8d给药组、术后16d给药组且同时各设0．9％氯化钠注射液对照组（n=6），于术前、术后及术后不同给药时间测定50％撤足阈值（PWT）。结果：①皮下给药组能明显的改善机械痛敏，坐骨神经表面及坐骨神经注射给药组机械痛敏改善不明显。②皮下给药组术后各不同时间给药小组，均能明显的改善机械痛敏，与对照组相比有统计学意义（P〈0．05）；给药后第15天效果最明显；这种镇痛作用持续至少20余天。③坐骨神经表面及坐骨神经注射给药组动物的机械痛敏改善不明显，与对照组相比无统计学意义（P〉0．05）。结论：皮下注射BTX—A，能改善L5VRT模型大鼠的机械痛敏，有镇痛作用，且为最佳给药途径。

Analgesic Effect and Approach of Botulinum Toxin Type A on Neuropathic Pain Model in Rats

Objective： To investigate the analgesic effect and explore the best approach of botulinum toxin type A （ BTX-A ） on neuropathic pain indued by lumbar 5 ventral root transection（ L5 VRT） in rats;Method： one Hundred and eight male SD rats were randomly divided into 3 groups （ n = 36）, BTX-A was administered to the plantar surface of the affected left hind paw, or was administered to the surface of the affected sciatic nerve, or was administered via the affected sciatic nerve injection, neuropathic pain was prepared by L5 VRT, Paw withdrawal threshold to mechanical stimulion were measured before surgery （baseline） and pastoperation different time. Result： Subcutaneous administration of BTX-A has significantly reduced mechanical alledynia in rats with L5 VRT （ P 〈 0.05 ） ,The effects of subcutaneous was significant on day 15 after administration BTX-A , and last more than 20 days; the group which administration BTX-A via the surface of sciatic nerve or the sciatic nerve injection shows no change of the mechanical allodynia（P 〉 0.05 ） ; Conclusion： Subcutaneous administration of BTX-A has significantly reduced mechanical allodynia in rats with L5 VRT and is the best approach.