The experimental study for the explication of mechanism and therapy on the joint contracture

研究一：阐明关节收缩机制的实验研究制动往往与肌肉弹性下降有关。这种情况被称为肌肉痉挛，但其机制尚不清楚。我们检测了大鼠比目鱼肌缩短位后1周、2周、4周、8周和12周的踝关节活动度、被动张力、肌节长度、肌内膜胶原纤维排列和肌肉组织中透明质酸的变化。踝关节活动度随制动时间的延长而降低。固定肌肉上的被动张力增加了。固定后1周肌节长度缩短，固定后2、4、8、12周肌节长度无进一步变化。制动后1周和2周，肌内膜胶原原纤维排列呈纵轴排列，而制动后4、8和12周则呈环状排列。肌内膜透明质酸呈…More在制动后1周升高，在2、4、8、12周保持在同一水平。组织化学显示，制动后肌肉组织内膜透明质酸染色较对照组织更深、更广。肌肉组织中透明质酸的增加可能会导致肌肉僵硬，但透明质酸与肌肉痉挛机制的关系尚不清楚。研究结果提示垫肌挛缩症在制动后1周开始，并随着制动时间的延长而加重。因此，肌挛缩在固定的早期阶段受到缩短的肌肉纤维的影响，之后胶原蛋白通过肌内膜中的纤维排列变得更圆周而适应。这种胶原纤维排列的变化可能导致在制动后期的肌肉痉挛。研究2：解释关节痉挛的治疗方法的实验研究1)确定延长拉伸是否能预防小鼠关节痉挛。研究发现，拉伸10分钟不能预防关节痉挛的进展，而拉伸20分钟或更长时间则可以防止关节痉挛的进展。但持续30分钟的拉伸并不能完全防止关节痉挛的进展。2)为了确定延长拉伸时间是否能改善固定的大鼠比目鱼肌的废用性肌肉萎缩。18只雄性Wistar大鼠随机分为对照组(n=3)和固定组(n=15)。制动组大鼠踝关节制动4周，随机分为3组：单纯制动组(I组，n=3)、活动后30min/d的拉伸训练1~3周组(S组，n=6)、活动后自然恢复1~3周组(NS组，n=6)。再通1周后，S组I型肌纤维直径较NS组明显增大。再通3周后，S组I、II型肌纤维直径较NS组明显增大。我们的研究结果表明，长时间的伸展可以从关节痉挛后的废用性肌肉萎缩中恢复。较少

Study 1 : The experimental study for the explication of mechanism on the joint contractureImmobilization is often associated with a decrease in muscle elasticity. This condition is called muscle contracture, but the mechanism is not yet clear. We examined changes in ankle joint mobility, passive tension, sarcomere length, collagen fibril arrangement in the endomysium, and hyaluronic acid in muscular tissue 1, 2, 4, 8, and 12 weeks after immobilization of rat soleus muscles in shortened position. Ankle joint mobility decreased with the duration of immobilization. Passive tension on immobilized muscles had increased. Sarcomere length had shortened 1 week after immobilization, but did not show further change 2, 4, 8, and 12 weeks after immobilization. Collagen fibril arrangement in the endomysium 1 and 2 weeks after immobilization was longitudinal to the axis of the muscle fibers, whereas 4, 8, and 12 weeks after immobilization it was circumferential.Hyaluronic acid in muscular tissue had … More increased 1 week after immobilization but remained at the same level at weeks 2, 4, 8, and 12. Histochemically, hyaluronic acid in the endomysium of immobilized muscular tissue was stained more strongly and widely than that in the control tissue. Increased hyaluronic acid in muscular tissue may induce muscle stiffness, but the significance of how hyaluronic acid is related to the mechanism of muscle contracture was not clear. The findings suggest mat muscle contracture started 1 week after immobilization and increased with the length of immobilization. Consequently, muscle contracture is affected by the shortening muscle fibers during the early stage of immobilization, after which the collagen adapts by the fibril arrangement in the endomysium becoming more circumferential. This change in collagen fibril arrangement may cause advanced muscle contracture in the late stage of immobilization.Study 2 : The experimental study for the explication of therapy on the joint contracture1) To determine whether prolonged stretching is preventing for joint contracture in mice. It was found that progression of joint contracture can not be prevented in periods of stretch lasting 10 min, and can prevent in periods of stretch lasting 20 min or more. But the progression of joint contracture can not completely prevented in periods of stretch lasting 30 min.2) To determine whether prolonged stretching is ameliorating for disuse muscle atrophy in immobilized rat soleus muscles. Eighteen male Wistar rats were divided randomly into control (n=3) and immobilization (n=15) groups. The immobilization groups rats were immobilized on ankle joint for 4 weeks, animals were divided into three groups : immobilization alone (group I, n=3), stretch training for 30 min/day for 1or 3 weeks after remobilization (group S, n=6), and spontaneous recovery (non stretch training) for 1 or 3 weeks after remobilization (group NS, n=6). After 1 week of remobilization, muscle fiber diameters for type I fibers in group S had increased significantly compared with group NS. After 3 weeks of remobilization, muscle fiber diameters for types I and II fibers in group S had increased significantly compared with group NS. Our findings suggest that prolonged stretching induces recovery from disuse muscle atrophy after joint contracture. Less