Human Performance Laboratory, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada.
J Biomech. 2011 Jan 4;44(1):39-44. doi: 10.1016/j.jbiomech.2010.08.020. Epub 2010 Sep 15.
Botulinum toxin type A (BTX-A) is a frequently used therapeutic tool to denervate muscles in the treatment of neuromuscular disorders. Although considered safe by the US Food and Drug Administration, BTX-A can produce adverse effects in target and non-target muscles. With an increased use of BTX-A for neuromuscular disorders, the effects of repeat injections of BTX-A on strength, muscle mass and structure need to be known. Therefore, the purpose of this study was to investigate the changes in strength, muscle mass and contractile material in New Zealand White (NZW) rabbits. Twenty NZW rabbits were divided into 4 groups: control and 1, 3 and 6 months of unilateral, repeat injections of BTX-A into the quadriceps femoris. Outcome measures included knee extensor torque, muscle mass and the percentage of contractile material in the quadriceps muscles of the target and non-injected contralateral hindlimbs. Strength in the injected muscles was reduced by 88%, 89% and 95% in the 1, 3 and 6 months BTX-A injected hindlimbs compared to controls. Muscle mass was reduced by 50%, 42% and 31% for the vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM), respectively, at 1 month, by 68%, 51% and 50% at 3 months and by 76%, 44% and 13% at 6 months. The percentage of contractile material was reduced for the 3 and 6 months animals to 80-64%, respectively, and was replaced primarily by fat. Similar, but less pronounced results were also observed for the quadriceps muscles of the contralateral hindlimbs, suggesting that repeat BTX-A injections cause muscle atrophy and loss of contractile tissue in target muscles and also in non-target muscles that are far removed from the injection site.
A型肉毒毒素（BTX-A）是一种常用于神经肌肉疾病治疗的神经肌肉去神经药物。尽管美国食品和药物管理局认为 BTX-A 是安全的，但 BTX-A 会在靶肌肉和非靶肌肉中产生不良反应。随着 BTX-A 在神经肌肉疾病中的应用增加，需要了解 BTX-A 重复注射对力量、肌肉质量和结构的影响。因此，本研究旨在研究新西兰白兔（NZW）重复注射 BTX-A 对股四头肌力量、肌肉质量和收缩物质的变化。20 只 NZW 兔随机分为 4 组：对照组和 1、3 和 6 个月单侧、重复注射 BTX-A 入股四头肌。观察指标包括膝关节伸肌力矩、目标肌肉和非注射对侧后肢股四头肌的肌肉质量和收缩物质百分比。与对照组相比，注射肌肉的力量在 1、3 和 6 个月 BTX-A 注射后肢分别减少了 88%、89%和 95%。1 个月时，股外侧肌（VL）、股直肌（RF）和股内侧肌（VM）的肌肉质量分别减少了 50%、42%和 31%，3 个月时减少了 68%、51%和 50%，6 个月时减少了 76%、44%和 13%。3 个月和 6 个月时收缩物质的百分比分别降至 80-64%，主要被脂肪替代。对侧后肢股四头肌也观察到类似但不那么明显的结果，这表明重复 BTX-A 注射会导致靶肌肉和远离注射部位的非靶肌肉发生肌肉萎缩和收缩组织丧失。
