Search for aquaporin molecules at the plasma membrane of normal skeletal myofibers and their alterations in myopathic muscles.

我们研究了正常骨骼肌中有哪些水通道蛋白分子表达，并将研究扩展到分析这些水通道蛋白分子在患病人体肌肉中的表达变化。对于正常骨骼肌中水通道蛋白分子的表达，分别在RNA和蛋白水平上对水通道蛋白0 ~ 10分子进行了搜索。RT - PCR检测RNA水平，免疫印迹和免疫细胞化学检测蛋白水平，结果证实AQP3、AQP4、AQP7分子在正常人骨骼肌纤维的RNA和蛋白水平均存在。AQP4分子在2型白色纤维（快抽动纤维）中比在1型红色纤维（慢抽动纤维）中表达更丰富，而AQP3分子在1型红色纤维中比在2型白色纤维中表达更丰富。AQP7分子在1型和2型人骨骼肌纤维中表达相同；而在正常小鼠骨骼肌中，AQP7…More在2型快肌纤维中的表达量高于1型慢肌纤维。aqp1据报道存在于骨骼肌组织的内皮细胞中；我们注意到aqp1存在于骨骼肌组织的肌纤维表面。正常骨骼肌骨折标签复制品电镜显示，AQP4的金信号位于肌纤维P面正交阵列，AQP3的金信号位于肌纤维P面颗粒簇。颗粒团簇是膜内颗粒的不规则聚集体，不同于正交阵列，正交阵列是4个以上颗粒形成矩形的规则颗粒聚集体。关于患病人体骨骼肌水通道蛋白分子表达的改变，在Fukuyama型先天性肌营养不良患者肌纤维表面蛋白水平上AQP4表达降低，AQP4 mRNA含量降低；在肌萎缩性侧索硬化症等神经源性萎缩肌的散在肌纤维中，AQP4表达也降低。少

We investigated what kind of aquaporin molecule is expressed in normal skeletal muscle and the investigation was extended to analyze the alteration of the expression of these aquaporin molecule in the diseased human muscles. With regard to the expression of aquaporin molecule in normal skeletal muscle, each of aquaporin 0〜10 molecule was searched at RNA and protein levels. The investigation of RNA level was carried out by RT PCR and that of protein level was performed by immunoblot and immunocytochemistry As the result, AQP3, AQP4 AQP7 molecules were confirmed to be present at RNA and protein levels in normal human skeletal myofibers. AQP4 molecule was more abundantly expressed in type 2 white fiber (fast twitch fiber) than in type 1 red fiber (slow twitch fiber): whereas AQP3 molecule was more abundantly expressed in type 1 red fiber than in type 2 white fiber. AQP7 molecule was equally expressed in type 1 and type 2 human skeletal myofibers; while in normal mouse skeletal muscle AQP7 … More was more abundantly expressed in type 2 fast twitch fiber than type 1 slow twitch fiber. AQP 1 is reported to be present at the endothelial cell within skeletal muscle tissue, however; we noticed that AQP 1 is present at the myofiber surface of skeletal muscle tissue. Electron microscopy of fracture label replica of normal skeletal muscle showed that gold signal of AQP4 was located in the orthogonal array of myofiber P face and that of AQP3 was located in the particle cluster of myofiber P face. Particle cluster is the irregular aggregate of intramembranous particles and is different from orthogonal array which is the regular particle aggregate more than 4 particles forming rectangular shape. With respect to the altered expression of aquaporin molecule in diseased human skeletal muscles, expression of AQP4 in muscles with Fukuyama type congenital muscular dystrophy was reduced in their myofiber surface at protein levels and the content of AQP4 mRNA was reduced AQP4 expression was also decreased in the scattered myofibers with neurogenic atrophy muscles such as muscles with amyotrophic lateral sclerosis. Less