The influence of cyclic concentric and eccentric submaximal muscle loading on cell viability in the rabbit knee joint
The influence of cyclic concentric and eccentric submaximal muscle loading on cell viability in the rabbit knee joint
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DOI：
10.1016/j.clinbiomech.2011.09.012
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发表时间：
2012-03-01
影响因子：
1.8
通讯作者：
Herzog, Walter
中科院分区：
文献类型：
--
作者：
Horisberger, Monika;Fortuna, Rafael;Herzog, Walter
背景资料：骨关节炎的发生和发展与骨钙素负荷有关，细胞死亡可能在这些过程中起重要作用。虽然对关节冲击负荷中的细胞死亡有很多了解，但没有关于肌肉收缩负荷的关节的信息。本研究的目的是评估肌肉产生的偏心和同心次最大关节负荷对软骨细胞活力的影响。我们假设，偏心肌肉激活导致增加细胞死亡率相比，同心负荷和controls.Methods：16只兔子接受50分钟的单侧，循环偏心（n = 8）或同心（n = 8）膝关节负荷。这些动态条件下的肌肉激活相当于产生20%最大等长力的激活水平。外侧关节作为未加载对照。细胞活力进行了评估，使用共聚焦microscopics.Findings：偏心收缩产生更大的膝关节负荷比同心收缩。与未加载的对照组相比，次最大收缩导致加载膝关节中细胞死亡显着增加，而偏心加载导致的细胞死亡显着多于同心加载。解释：膝关节的循环次最大肌肉加载导致兔软骨细胞死亡增加。这些发现表明，长期低水平的关节负荷，如耐力运动或体力劳动，可能会导致软骨细胞死亡，从而使关节容易退化。(C)2011爱思唯尔有限公司版权所有。
Background: Cartilage loading is associated with the onset and progression of osteoarthritis and cell death may play an important role in these processes. Although much is known about cell death in joint impact loading, there is no information on joints loaded by muscular contractions. The aim of this study was to evaluate the influence of muscle generated eccentric and concentric submaximal joint loading on chondrocyte viability. We hypothesised that eccentric muscle activation leads to increased cell death rates compared to concentric loading and to controls.Methods: 16 rabbits received either 50 min of uni-lateral, cyclic eccentric (n = 8) or concentric (n = 8) knee loading. Muscle activation for these dynamic conditions was equivalent to an activation level that produced 20% of maximum isometric force. Contralateral joints served as unloaded controls. Cell viability was assessed using confocal microscopy.Findings: Eccentric contractions produced greater knee loading than concentric contractions. Sub-maximal contractions caused a significant increase in cell death in the loaded knees compared to the unloaded controls, and eccentric loading caused significantly more cell death than concentric loading.Interpretation: Cyclic sub-maximal muscle loading of the knee caused increased chondrocyte death in rabbits. These findings suggest that low levels of joint loading for prolonged periods, as occurs in endurance exercise or physical labour, may cause chondrocyte death, thereby predisposing joints to degeneration. (C) 2011 Elsevier Ltd. All rights reserved.