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研究运动激活的CaMK Ⅱ对骨骼肌细胞核内MEF2/GLUT4 DNA结合活性及骨骼肌细胞内GLUT4基因表达量的调节作用。方法:两月龄C57BL/6J小鼠40只,按体重随机分为安静对照(control,C)、运动组(exercise,E)、运动+KN93组(KN93,93)、运动+KN92(KN92,92)组。Western Blotting法测CaMK II THR286磷酸化水平。EMSA法测MEF2/GLUT4 DNA结合活性。实时荧光定量PCR法测骨骼肌GLUT4 mRNA表达量。结果:1)运动+KN93组小鼠1 h跑台运动后,其骨骼肌细胞核内MEF2/GLUT4 DNA结合活性及骨骼肌细胞内GLUT4基因表达量,均显著低于单纯运动组。运动+KN92组小鼠1 h跑台运动后,骨骼肌CaMKⅡ活性,MEF2/GLUT4 DNA结合活性及骨骼肌细胞内GLUT4基因表达量与单纯跑台运动组相比均无显著差异。2)虽然运动+KN93组小鼠1 h跑台运动后骨骼肌GLUT4基因表达量显著低于单纯运动组,但与安静对照组相比,仍显著增加。结论:虽然CaMK Ⅱ参与调节运动诱导的MEF2/GLUT4 DNA结合活性及骨骼肌细胞内GLUT4基因表达量的升高,但CaMKⅡ并不是调节运动诱导的GLUT4基因和蛋白表达增多的唯一信号通路,机体还存在其他的调节信号机制。
To investigate the modulation of MEF2 / GLUT4 DNA binding activity in the nucleus of skeletal muscle cells and the expression of GLUT4 gene in skeletal muscle cells by exercise-activated CaMKII. METHODS: Forty two-month-old C57BL / 6J mice were randomly divided into control, C, exercise, E, KN93, KN92, KN92, 92) group. The phosphorylation level of CaMK II THR286 was measured by Western Blotting. EMSA assay MEF2 / GLUT4 DNA binding activity. Real - time quantitative PCR method for measuring GLUT4 mRNA expression in skeletal muscle. Results: 1) MEF2 / GLUT4 DNA binding activity in skeletal muscle nuclei and GLUT4 gene expression in skeletal muscle cells were significantly lower in exercise + KN93 group than those in simple exercise group after 1 h treadmill exercise. Exercise + KN92 group 1 h treadmill exercise, skeletal muscle CaMK Ⅱ activity, MEF2 / GLUT4 DNA binding activity and skeletal muscle cells GLUT4 gene expression levels compared with simple treadmill exercise group were no significant differences. 2) Although the expression of GLUT4 gene in skeletal muscle was significantly lower in exercise + KN93 group than that in simple exercise group at 1 h treadmill exercise, it still increased significantly compared with that in control group. Conclusions Although CaMK Ⅱ is involved in the regulation of MEF2 / GLUT4 DNA-binding activity and the expression of GLUT4 in skeletal muscle cells, CaMKⅡ is not the only signal pathway that regulates exercise-induced GLUT4 gene and protein expression. There are other regulatory signaling mechanisms.