Sato Eugene J, Killian Megan L, Choi Anthony J, Lin Evie, Choo Alexander D, Rodriguez-Soto Ana E, Lim Chanteak T, Thomopoulos Stavros, Galatz Leesa M, Ward Samuel R
Departments of Bioengineering (E.J.S., A.E.R.-S., and S.R.W.), Radiology (S.R.W.), and Orthopaedic Surgery (A.J.C., E.L., A.D.C., and S.R.W.), University of California San Diego, 9500 Gilman Drive (0610), La Jolla, CA 92093. E-mail address for S.R. Ward:
Department of Orthopaedic Surgery, Washington University, 660 South Euclid Avenue, St. Louis, MO 63110. E-mail address for L.M. Galatz:
J Bone Joint Surg Am. 2015 Apr 1;97(7):565-73. doi: 10.2106/JBJS.M.01503.
Injury to the rotator cuff can cause irreversible changes to the structure and function of the associated muscles and bones. The temporal progression and pathomechanisms associated with these adaptations are unclear. The purpose of this study was to investigate the time course of structural muscle and osseous changes in a rat model of a massive rotator cuff tear.
Supraspinatus and infraspinatus muscle architecture and biochemistry and humeral and scapular morphological parameters were measured three days, eight weeks, and sixteen weeks after dual tenotomy with and without chemical paralysis via botulinum toxin A (BTX).
Muscle mass and physiological cross-sectional area increased over time in the age-matched control animals, decreased over time in the tenotomy+BTX group, and remained nearly the same in the tenotomy-alone group. Tenotomy+BTX led to increased extracellular collagen in the muscle. Changes in scapular bone morphology were observed in both experimental groups, consistent with reductions in load transmission across the joint.
These data suggest that tenotomy alone interferes with normal age-related muscle growth. The addition of chemical paralysis yielded profound structural changes to the muscle and bone, potentially leading to impaired muscle function, increased muscle stiffness, and decreased bone strength.
Structural musculoskeletal changes occur after tendon injury, and these changes are severely exacerbated with the addition of neuromuscular compromise.
肩袖损伤可导致相关肌肉和骨骼的结构与功能发生不可逆变化。与这些适应性变化相关的时间进程和病理机制尚不清楚。本研究的目的是在大鼠巨大肩袖撕裂模型中研究肌肉和骨骼结构变化的时间进程。
在采用肉毒杆菌毒素A（BTX）进行双侧肌腱切断术并伴有或不伴有化学麻痹的三天、八周和十六周后，测量冈上肌和冈下肌的肌肉结构、生化指标以及肱骨和肩胛骨的形态学参数。
在年龄匹配的对照动物中，肌肉质量和生理横截面积随时间增加；在肌腱切断术+BTX组中，随时间减少；而在单纯肌腱切断术组中几乎保持不变。肌腱切断术+BTX导致肌肉中细胞外胶原蛋白增加。在两个实验组中均观察到肩胛骨形态的变化，这与关节负荷传递的减少一致。
这些数据表明，单纯肌腱切断术会干扰与年龄相关的正常肌肉生长。添加化学麻痹会使肌肉和骨骼发生深刻的结构变化，可能导致肌肉功能受损、肌肉僵硬增加和骨强度降低。
肌腱损伤后会发生肌肉骨骼结构变化，而神经肌肉功能受损会使这些变化严重加剧。
