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

结果表明，在发育过程中（1 ~ 25周），DIA和STM肌纤维直径、终板体积、终板面积和终板核数均显著增加，终板核数、终板面积和终板核数均显著增加。MuSK mRNA的表达水平在发育过程中下降60%，并在出生后130周内保持恒定值。而SHP 2 mRNA的表达水平在整个发育过程中基本保持不变，到130周时逐渐增加。DIA组MuSK和SHP 2 mRNA表达水平显著高于STM组。这些结果表明，在出生后发育过程中，终板的扩大主要受MuSK表达的调控，而终板的碎裂主要受SHP 2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.