骨骼肌内源性生肌因子成肌活性随衰老下降  

Myogenic Activity of Intrinsic Myogenic Factor Decreases with the Aging of Skeletal Muscle

作　　者：蔡冬青[1] 李明[2] 陈启明[3] 沈晓涛[1] 李震 陈美翩 曹亮 李嘉豪[4] 

机构地区：[1]暨南大学生物医学工程系,广州510632 [2]香港中文大学医学院内科与治疗系 [3]香港中文大学医学院矫形外科和创伤学系 [4]香港中文大学医学院解剖系

出　　处：《中国运动医学杂志》2005年第3期273-278,共6页Chinese Journal of Sports Medicine

基　　金：国家自然科学基金项目 (30 340 0 38) ;暨南大学引进人才基金项目 (6 92 0 36 );香港政府创新科学基金项目(GrantNo .UIM/ 12 1;ProjectNo .6 90 16 0 7)资助。

摘　　要：目的:观察和探讨骨骼肌内源性生肌因子(39kDa)成肌活性随衰老而发生的改变。方法:应用等电聚焦结合聚丙稀酰胺凝胶电泳多步功能测试分筛法对青年和老年大鼠骨骼肌内源性39kDa生肌因子进行分离,利用体外培养和体内模型对青年和老年大鼠骨骼肌生肌因子的成肌活性进行比较,采用增殖细胞抗原(PCNA)免疫组织化学技术观察生肌因子对骨骼肌干细胞—卫星细胞的增殖作用。结果:处理组大鼠骨骼肌内源性39kDa生肌因子C2C12细胞数目显著多于对照组,处理组39kDa生肌因子MTT值显著高于对照组(P <0 . 0 5 )。青年和老年生肌因子处理组都有相当一部分C2C12细胞融合形成肌管,但青年大鼠骨骼肌生肌因子融合形成的肌管数目显著多于老年大鼠。体内研究发现:注射39kDa生肌因子的青年大鼠胫骨前肌中有许多PCNA阳性细胞核,但在对照组中未发现PCNA阳性细胞核。然而,在经注射的老年大鼠胫骨前肌中只发现少量PCNA阳性细胞核。PCNA阳性细胞核半定量计数结果表明:经生肌因子注射的青年大鼠胫骨前肌PCNA阳性细胞核显著多于老年大鼠(P <0 .0 5 )。本研究结果提示:39kDa生肌因子能诱导骨骼肌干细胞—卫星细胞的增殖和分化,青年大鼠骨骼肌中39kDa生肌因子的成肌活性高于老年大鼠。Objective To investigate the changes in myogenic activity of an intrinsic myogenic facotor （39kDa） in vitro and in vivo with aging of skeletal muscle. Methods The young and old intrinsic myogenic factors （39kDa） were isolated by isoelectric focusing and sodium dodecyl sulfate - polyacrylimide gel electrophoresis combing with functional activity assay. The myogenic activities between the young and old were compared in C2C12 cell culture and in vivo injection. The immunostaining of proliferating cell nuclear antigen （PCNA） was applied to investigate the proliferation of skeletal muscle stem cell - satellite cell. Results In vitro studies showed that the C2C12 cell number in 39kDa myogenic factor treated group was significantly higher than that in control. However, the myogenic activity of 39kDa myogenic factor originated from young muscle was higher than that from the old muscle. This finding was also confirmed quantitatively by MTT assay （ P 〈 0.05 ）. In addition, myotubes were found in the young and old 39kDa myogenic factor treated groups, but not in the control. The number of myotube in the young myogenic factor treated group was higher than that in the old myogenic factor treated group. In vivo studies showed that there were many PCNA - positive nuclei in the young tibialis anterior （TIA） muscle injected with 39kDa, while there is no detectable PCNA - positive nuclei in the young control. In contrast, only a few PCNA - positive nuclei were found in the old TIA muscle injected with 39kDa, like in the young control, there is no detectable PCNA - positive nuclei in the old control. Num- ber count analysis demonstrated that PCNA - positive nuclei in the young treated TIA muscle was higher than that in the old treated TIA muscle （ P 〈 0. 05）. Conclusion 39kDa intrinsic myogenic factor could trigger the proliferation and differentiation of satellite cells. The young 39kDa myogenic factor possessed higher myogenic activity than that of the old 39kDa myogenic factor. The reduction of myogen

关 键 词：骨骼肌 内源性生肌因子 老化 骨骼肌干细胞 生肌因子 内源性 活性 衰老 免疫组织化学技术 老年大鼠 

分 类 号：R33[医药卫生—人体生理学]