Membrane abnormalities and Ca homeostasis in muscles of the mdx mouse, an animal model of the Duchenne muscular dystrophy: A review
Membrane abnormalities and Ca homeostasis in muscles of the mdx mouse, an animal model of the Duchenne muscular dystrophy: A review
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DOI：
10.1046/j.1365-201x.1996.201000.x
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发表时间：
1996-03-01
期刊：
影响因子：
--
通讯作者：
Gillis, JM
中科院分区：
文献类型：
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作者：
Gillis, JM
MDX小鼠的肌肉缺乏肌营养不良蛋白，这是一种细胞骨架蛋白。MDX纤维对低渗休克和强迫伸长表现出更大的脆性。拉伸敏感型钙通道的异常开放时间。[Ca~(2+)](I)值的慢性升高是一个有争议的问题。我们分析了成年MDX小鼠肌肉和骨骼肌中钙的动态平衡。输精管壁内含钙荧光指示剂Fura-P-AM(细胞可扩散)。测定静息[Ca~(2+)](I)变化后、KCI或电刺激后[Ca~(2+)](I)的变化。用胶原酶处理指短屈肌分离出单条横纹纤维，并用Fura-2-AM负载。静息[Ca~(2+)](I)用Fura-2考虑钙缓冲的原位校准程序测量。未证实细胞内钙离子的慢性升高。细胞内钙结合蛋白小白蛋白的表达。是经过测量的。在快速的MDX肌肉(胫骨前肌)中，它增加了大约三倍，但在比目鱼肌中仍然检测不到。据推测，小白蛋白有助于将[Ca~(2+)](I)维持在正常值内。这一假说将结合突变犬和人类患者的营养不良表型进行讨论。
Muscles of ?he mdx mouse lack dystrophin, a cytoskeletal protein. Mdx fibres exhibit an increased fragility to hypo-osmotic shock and to forced lengthening. an abnormal opening time of stretch-sensitive calcium channels. The question of a chronic elevated [Ca2+](i) value is a matter of controversy.We have analysed Ca homeostasis in smooth and skeletal muscles from the adult mdx mouse. The wall of the vas deferens was loaded with the fluorescent Ca indicator Fura-P-AM (cell-diffusible). Resting [Ca2+](i) was measured after changes of the electrochemical potential for Ca2+ and after KCI or electrical stimulations. In no instance was a difference observed between these and similar muscles from control mice.Single striated fibres were isolated by collagenase treatment of the flexor digitorum brevis muscle and loaded with Fura-2-AM. The value of resting [Ca2+](i) was measured using an in situ calibration procedure which took account of Ca buffering by Fura-2. A chronic increase of cytosolic Ca2+ was not confirmed.The expression of the intracellular Ca-binding protein, parvalbumin. was measured. It increased by about threefold in fast mdx muscles (tibialis anterior) but remained undetectable in the soleus. It is hypothesized that parvalbumin helps to maintain [Ca2+](i) within normal values. This hypothesis will be discussed in connection with dystrophy phenotypes in mutant dogs and in human patients.