Age-related Change in Endplate morphology and its regulatory factors in rat muscles

我们检测了衰老大鼠肌肉终板细胞核的数量、运动终板的形态学特征以及肌肉特异性激酶（MuSK）和两个SH2结构域酪氨酸磷酸酶（Shp2）的表达水平。在发育期间（1 ~ 25周），DIA和STM肌肉的肌纤维直径、终板体积和表面积以及终板细胞核数量均显著增加。在发育期间，麝香mRNA的表达水平下降了60%，并在出生后130周保持不变。而SHP2 mRNA的表达水平在发育期保持不变，并在130周时逐渐升高。与STM肌肉相比，DIA肌肉中MuSK和SHP2 mRNA的表达水平显著升高。这些结果表明，终板的增大主要受出生后发育过程中MuSK表达的调控，终板的破碎主要受衰老过程中SHP2表达的调控。

We examined the number of endplate nuclei, morphological properties of the motor endplate, and the expression level of muscle-specific kinase (MuSK) and tyrosine phosphatase with two SH2 domains (Shp2) in rat muscles with aging.During the developmental period (1 to 25 weeks), the muscle fiber diameter, endplate volume and surface area, and number of endplate nuclei were significantly increased in both DIA and STM muscles. The level of MuSK mRNA expression was decreased by 60% during the developmental period and kept constant values to 130 weeks after birth. While, the level of SHP2 mRNA expression kept constant value during the developmental period and increased to 130 weeks. There were significantly higher levels of MuSK and SHP2 mRNA expression in DIA than those in STM muscles. These results suggested that enlargement of endplate is mainly regulated by MuSK expression during postnatal development, and that fragmentation of endplate is mainly regulated by SHP2 expression with aging.