Altered muscle force and stiffness of skeletal muscles in alpha-sarcoglycan-deficient mice.
Altered muscle force and stiffness of skeletal muscles in alpha-sarcoglycan-deficient mice.
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α-肌聚糖缺陷小鼠的肌肉力量和骨骼肌硬度发生改变。
DOI：
10.1152/ajpcell.00326.2002
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Boriek,AladinM
中科院分区：
文献类型：
--
作者：
Patel,NishaD;Jannapureddy,SunealR;Hwang,Willy;Chaudhry,Imran;Boriek,AladinM
α-葡聚糖(Asg)是抗肌营养不良蛋白相关复合体的跨膜蛋白，缺乏Asg会导致四肢带状肌营养不良。我们推测，肌聚糖复合体的破坏可能会改变肌肉的延伸性，并破坏横轴收缩元件在隔膜中的偶联。我们测定了幼年ASG缺陷小鼠和对照小鼠在单轴和双轴加载过程中横隔膜的长度-张力关系。我们还测定了在没有和存在被动横向应力的情况下，突变小鼠和正常小鼠的横隔肌的等长收缩特性。我们发现，ASG蛋白缺失突变体的横隔肌表现为：1)肌纤维方向和横向的肌肉延伸性显著降低，2)力量产生能力显著降低，3)纵向和横向特性之间的耦合显著降低。因此，这些发现表明，肌聚糖复合体通过促进肌肉被动僵硬和调节肌肉的收缩特性，在横隔膜中发挥机械功能。
α-Sarcoglycan (ASG) is a transmembrane protein of the dystrophin-associated complex, and absence of ASG causes limb-girdle muscular dystrophy. We hypothesize that disruption of the sarcoglycan complex may alter muscle extensibility and disrupt the coupling between passive transverse and axial contractile elements in the diaphragm. We determined the length-tension relationships of the diaphragm of young ASG-deficient mice and their controls during uniaxial and biaxial loading. We also determined the isometric contractile properties of the diaphragm muscles from mutant and normal mice in the absence and presence of passive transverse stress. We found that the diaphragm muscles of the null mutants for the protein ASG show1) significant decrease in muscle extensibility in the directions of the muscle fibers and transverse to fibers,2) significant reductions in force-generating capacity, and3) significant reductions in coupling between longitudinal and transverse properties. Thus these findings suggest that the sarcoglycan complex serves a mechanical function in the diaphragm by contributing to muscle passive stiffness and to the modulation of the contractile properties of the muscle.