Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region, Kowloon, Hong Kong, PR China. rsgng@ polyu.edu.hk
Connect Tissue Res. 2011;52(6):466-71. doi: 10.3109/03008207.2011.562334. Epub 2011 May 18.
Enforced downhill running has been reported to induce tendinosis in the rat supraspinatus tendon but similar exercise failed to induce Achilles tendinosis in this animal. Due to the presence of acromial arch in the shoulder, accessing the supraspinatus tendon with physical modalities is difficult; thus this model may not be suitable for studying the treatment for tendinosis. To develop a rat model for Achilles tendinosis, we tested 14 mature Sprague-Dawley rats by dividing them into 2 groups of 7 each. The experimental group was subjected to a daily enforced downhill bipedal running program by suspending their upper bodies so that they ran with their hind limbs on a treadmill for 1 hr/day for 8 weeks. The downward inclination was 20 degrees and the speed was 17 m/min. The animals in the control group did not undergo any exercise. After 8 weeks, the Achilles tendons were harvested and subjected to histological and biomechanical analysis. Histological examination revealed tenocyte proliferation, change in tenocytes appearance, and collagen bundle disintegration in the running group. The biomechanical testing revealed significant decrease in stiffness (p = 0.002) and ultimate tensile strength (p = 0.016) in the running group than in the control group. Both the histological and biomechanical findings are suggestive of changes in the tendon of the running group that resembled the pathological changes of tendinosis in human. This new model of Achilles tendinosis in rat will be useful for studying the etiology and subsequent management strategies of this condition.
强制下坡跑已被报道可诱导大鼠冈上肌腱腱病，但类似的运动未能在这种动物中诱导跟腱腱病。由于肩部存在肩峰弓，使用物理疗法很难触及冈上肌腱；因此，这种模型可能不适合研究腱病的治疗方法。为了开发一种用于研究跟腱腱病的大鼠模型，我们将 14 只成熟的 Sprague-Dawley 大鼠分为两组，每组 7 只。实验组通过悬挂上半身，使它们用后腿在跑步机上以每天 1 小时、8 周的时间进行强制下坡双足跑步，每天进行下坡双足跑步。下坡角度为 20 度，速度为 17 m/min。对照组的动物不进行任何运动。8 周后，收获跟腱并进行组织学和生物力学分析。组织学检查显示实验组的腱细胞增殖、腱细胞形态改变和胶原纤维束解体。生物力学测试显示，实验组的刚度（p = 0.002）和最大拉伸强度（p = 0.016）明显低于对照组。实验组的组织学和生物力学发现均提示跟腱发生变化，类似于人类腱病的病理变化。这种新的大鼠跟腱腱病模型将有助于研究这种疾病的病因和后续的管理策略。
