Faculty of Kinesiology, University of Calgary, Calgary, Canada.
Calcif Tissue Int. 2010 Dec;87(6):541-9. doi: 10.1007/s00223-010-9428-2. Epub 2010 Oct 22.
Studies to date have assumed that botulinum toxin type A (BTX) affects bone indirectly, through its action on muscle. We hypothesized that BTX has no discernable effect on bone morphometry, independent of its effect on muscle. Therefore, we investigated whether BTX had an additional effect on bone when combined with tenotomy compared to tenotomy in isolation. Female BALB/c mice (n = 73) underwent one of the following procedures in the left leg: BTX injection and Achilles tenotomy (BTX-TEN), BTX injection and sham surgery (BTX-sham), Achilles tenotomy (TEN), or sham surgery (sham). BTX groups were injected with 20 μL of BTX (1 U/100 g) in the posterior lower hindlimb. At 4 weeks, muscle cross-sectional area (MCSA) and tibial bone morphometry were assessed using micro-CT. Each treatment, other than sham, resulted in significant muscle and bone loss (P < 0.05). BTX-TEN experienced the greatest muscle loss (23-45% lower than other groups) and bone loss (20-30% lower bone volume fraction than other groups). BTX-sham had significantly lower MCSA and bone volume fraction than TEN and sham. After adjusting for differences in MCSA, there were no significant between-group differences in bone properties. We found that BTX injection resulted in more adverse muscle and bone effects than tenotomy and that effects were amplified when the procedures were combined. However, between-group differences in bone could be accounted for by MCSA. We conclude that any independent effect of BTX on bone morphometry is likely small or negligible compared with the effect on muscle.
迄今为止的研究假设肉毒杆菌毒素 A（BTX）通过其对肌肉的作用间接影响骨骼。我们假设 BTX 对骨骼形态计量学没有明显影响，与对肌肉的影响无关。因此，我们研究了当 BTX 与跟腱切断术联合使用时是否与单独跟腱切断术相比对骨骼有额外的影响。雌性 BALB/c 小鼠（n = 73）在左腿接受以下一种手术：BTX 注射和跟腱切断术（BTX-TEN）、BTX 注射和假手术（BTX-sham）、跟腱切断术（TEN）或假手术（sham）。BTX 组在后腿下部后肢注射 20 μL BTX（1 U/100 g）。在 4 周时，使用 micro-CT 评估肌肉横截面积（MCSA）和胫骨骨骼形态计量学。除 sham 外，每种治疗方法都导致肌肉和骨骼明显丢失（P < 0.05）。BTX-TEN 经历了最大的肌肉丢失（比其他组低 23-45%）和骨丢失（比其他组低 20-30%的骨体积分数）。BTX-sham 的 MCSA 和骨体积分数明显低于 TEN 和 sham。在调整 MCSA 的差异后，各组间的骨特性没有显著差异。我们发现 BTX 注射导致比跟腱切断术更严重的肌肉和骨骼影响，并且当两种手术联合使用时，影响会放大。然而，各组间的骨差异可以用 MCSA 来解释。我们得出结论，与对肌肉的影响相比，BTX 对骨骼形态计量学的任何独立影响可能很小或可以忽略不计。
