Yin Li-Qin, Li Fan-Ling, Tang Chang-Fa, Tao Xia, Liu Wen-Feng, Huang Hong-Bo, Deng Yong, Tang Lin
Physical Education, Hunan Norma University Changsha 410012.
Physical Education, Hunan University of Technology, Zhuzhou 412008.
Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2017 Apr 8;33(4):360-364. doi: 10.12047/j.cjap.5462.2017.087.
To study the effect of different intensity exercise on skeletal muscle fiber myosin heavy chain(MHC) subtype transformation and CaN/NFATc1 signaling pathways.
Twenty-four Male SD rats (2-month old) were randomly divided into normal control group (NC), moderate intensity exercise group (ME, grade 5°, speed 18 m/min), heavy intensity exercise group (HE, grade 10°, 26.8 m/min). The rats in exercise groups were treated with treadmill training for eight weeks. The type I and type Ⅱ muscle fibers were determined by ATPase staining method. MHC subtype was separated by SDS-PAGE. The activity of CaN was determined by colorimetric method. The content of NFATc1 protein in skeletal muscle was detected by immune imprinting technology.
①Skeletal muscle fiber density changes:the type I and Ⅱ fiber number density of quadriceps in ME group were increased significantly (<0.05), but in HE group, only the type Ⅱ fiber surface density was increased significantly (<0.05). The type I fiber number density of soleus in ME and HE group was increased significantly (<0.05). ②The changes of fibers MHC subtype percentage in skeletal muscle:the percentages of MHC I and type Ⅱa of quadriceps in ME group were increased (<0.05), while the percentage of MHC Ⅱb was decrease (<0.05). The percentage of MHC I in soleus was increased, while the percentages of MHCⅡa and Ⅱb were decreased. ③The activity of CaN and the content of NFATc1 protein in ME group were increased significantly (<0.05).
The heavy and moderate intensity exercise may induce skeletal muscle MHC type transforming from fast to slow. At the same time, the activity of CaN and the expression of NFATc1 protein are increased accompanying the changes of skeletal muscle fibers subtype.
研究不同强度运动对骨骼肌纤维肌球蛋白重链（MHC）亚型转化及CaN/NFATc1信号通路的影响。
将24只2月龄雄性SD大鼠随机分为正常对照组（NC）、中等强度运动组（ME，坡度5°，速度18米/分钟）、高强度运动组（HE，坡度10°，速度26.8米/分钟）。运动组大鼠进行为期8周的跑台训练。采用ATP酶染色法测定Ⅰ型和Ⅱ型肌纤维。通过SDS-PAGE分离MHC亚型。采用比色法测定CaN活性。用免疫印迹技术检测骨骼肌中NFATc1蛋白含量。
①骨骼肌纤维密度变化：ME组股四头肌Ⅰ型和Ⅱ型纤维数量密度显著增加（<0.05），而HE组仅Ⅱ型纤维面密度显著增加（<0.05）。ME组和HE组比目鱼肌Ⅰ型纤维数量密度显著增加（<0.05）。②骨骼肌纤维MHC亚型百分比变化：ME组股四头肌MHCⅠ型和Ⅱa型百分比增加（<0.05），而MHCⅡb型百分比降低（<0.05）。比目鱼肌MHCⅠ型百分比增加，而MHCⅡa型和Ⅱb型百分比降低。③ME组CaN活性和NFATc1蛋白含量显著增加（<0.05）。
高强度和中等强度运动可能诱导骨骼肌MHC类型由快向慢转变。同时，随着骨骼肌纤维亚型的变化，CaN活性及NFATc1蛋白表达增加。
