运动对大鼠骨骼肌CaMKⅡ磷酸化水平及核内PGC-1、HDAC5蛋白含量的影响

Effects of Exercise on CaMKⅡ Phosphorylation and Nuclear PGC-1α/HDAC5 Protein Expression in Rats Skeletal Muscle

目的:研究运动后不同时间大鼠骨骼肌CaMKⅡ磷酸化水平及核内PGC-1、HDAC5蛋白含量的变化,以探讨运动后PGC-1α基因表达时相性变化的调节机制。方法:9周龄的雄性Wistar大鼠(167±4)g 48只,随机分成安静对照组(C)和跑台运动后0 h、3 h、6 h、12 h、24 h取材组,共6组,每组8只。大鼠进行0坡度的1 h跑台运动,跑台速度34 m/min。Western blot法测定蛋白含量及磷酸化水平,RT-PCR法测定基因表达。结果:PGC-1αmRNA含量,运动后即刻变化不显著,运动后3 h、6 h显著增加,12 h虽仍高于对照组,但与6 h相比显著降低,24 h恢复至安静水平。核内PGC-1α蛋白含量运动后各取材点均无显著变化。核内HDAC5蛋白含量则在运动后3 h、6 h下降显著,12 h虽仍低于对照组,但与6h相比显著增加,24 h恢复到安静组水平。CaMKⅡ磷酸化水平,运动后0 h,3 h显著升高,6 h虽仍高于对照组,但与3 h相比显著降低,12 h恢复至安静水平。结论:运动后PGC-1α基因表达的时相性变化可能是由对应时相变化规律的CaMKⅡ通过调节核内HDAC5含量,解除了转录因子对PGC-1α基因转录的抑制而实现。

Objective： The phosphorylation activity of CaMK Ⅱ , nuclear PGC-1α and HDAC5 protein content was measured to explore the mechanism of the phasic change of PGC-1α gene expression after treadmill running. Methods： 48 nine week-old male Wister rats （167±4g） were randomly assigned to the Control group and five different groups that were measured at Oh, 3h, 6h, 12h and 24h after exercise. Rats undertook treadmill running for 1 hour at 0° slope. Results： Compared to the Control group, the expression of PGC-1α mRNA was greatly increased 3h and 6h after exercise. Though the abundance of PGC-1α mRNA decreased 12h after exercise, it＇s still higher than that in control group and it returns to normal at 24h after exercise. The expression of nuclear PGC-1α protein was unchanged after exercise. The expression of nuclear HDAC5 significantly decreased 3h and 6h after exercise, the 12h group increased greatly compared to the 6h group, though it＇s still lower than the control group and it returns to normal at 24h after exercise. Compared to the control group, the phosphorylation activity of CaMK Ⅱ was greatly increased Oh and 3h after exercise. Though the phosphorylation activity of CaMKⅡ de- creased 6h after exercise, it＇s still higher than the control group and it returns to normal at 12h after exercise. Conclusion： Phasic change of the expression of PGC-1α mRNA in rat skeletal muscle was observed in this study, and this is possibly induced by CaMKⅡ which lead the HDAC5 out of the nucleus.