Program in Physical Therapy and Rehabilitation Sciences, School of Medicine, University of Minnesota, Minneapolis, USA.
Am J Phys Med Rehabil. 2010 Dec;89(12):976-85. doi: 10.1097/PHM.0b013e3181fc7c9e.
Contractures are a major clinical issue for patients with muscular dystrophies. However, it is unknown whether contractures are present in the widely used mdx mouse model of Duchenne muscular dystrophy. Therefore, the objectives of this study were to develop methods to measure muscle contractures in mice, to determine whether plantarflexion contractures are present in mdx mice, and to analyze the composition of the major muscles involved.
Hindlimbs of eight wild type and six mdx mice were assessed every 2 wks during the course of a 12-wk study. Assessments included range of motion and in vivo torques about the ankle. At the end of the study, mice were euthanized, and muscles were analyzed for composition.
The mdx mice had ∼10 degrees less dorsiflexion, increased passive torque moving the ankle into dorsiflexion, and an increased passive-to-active torque ratio relative to wild type mice. Gastrocnemius muscle composition alterations included increased wet mass, decreased protein content, and increased collagen.
The results indicate that mdx mice have plantarflexion contractures similar to those seen in children with Duchenne muscular dystrophy. In future studies, these measures can be used to assess strategies to slow the progression of contractures that occur with muscular dystrophies.
肌肉萎缩症患者存在严重的临床挛缩问题。但目前尚不清楚杜氏肌营养不良症的常用 mdx 小鼠模型是否存在挛缩。因此，本研究的目的是开发测量小鼠肌肉挛缩的方法，确定 mdx 小鼠是否存在跖屈挛缩，并分析主要受累肌肉的组成。
在为期 12 周的研究过程中，每隔 2 周评估 8 只野生型和 6 只 mdx 小鼠的后肢。评估包括踝关节的运动范围和体内扭矩。研究结束时，处死小鼠并分析肌肉组成。
mdx 小鼠的背屈度减少约 10 度，被动扭矩使踝关节进入背屈增加，与野生型小鼠相比，被动到主动扭矩比增加。比目鱼肌的组成变化包括湿重增加、蛋白含量减少和胶原增加。
结果表明，mdx 小鼠存在类似杜氏肌营养不良症患儿的跖屈挛缩。在未来的研究中，这些措施可用于评估减缓与肌肉萎缩症相关的挛缩进展的策略。
