Objective: To investigate the effects of aerobic versus resistance exercise on soleus muscle contractile properties and the expressions of MuRF1, PGC-1α and FNDC5 in amyotrophic rats after unloading, and the possible molecular biological mechanisms. Methods: Male Wistar rats were randomly divided into recovery group (CT), aerobic exercise group (A), resistance exercise group (R) and control group (C), with 6 rats in each group. The control group did not receive any treatment. The other three groups underwent tail suspension for 2 weeks, and then the recovery group recovered quietly. The aerobic group and the resistance group underwent a 2-week exercise intervention. Exercise plan: the aerobic group rats were treated with treadmill speed corresponding to 65% maximum oxygen uptake (VO2max), 60 min/d, 5 d/w; the rats in the resistance group were allowed to climb the ladder with 65% of the maximum voluntary weight-bearing (MVCC) for 3 times, with a total of 5 sets. Each time had a rest of 1 min, with an interval of 2 min among sets, and 5 d/w. Fasting for 24 hours after the last exercise, the soleus muscle samples were collected to observe the histological changes, test the contractility, and detect MuRF1 and PGC-1α and FNDC5 expressions. Results: compared with the control group, the body weight, soleus muscle wet weight, average cross-sectional area of muscle fibers and muscle contractility of the recovery group were decreased significantly(P<0.01), and the expression of MuRF1 was increased significantly(P<0.01). Compared with the recovery group, the body weight, wet weight of soleus muscle, the average cross-sectional area of muscle fiber and muscle contractility of rats in aerobic group and resistance group were increased (P<0.01), the expression of PGC-1α/FNDC5 was increased (P<0.01) and the expression of MuRF1 was decreased significantly (P<0.01). Compared with the aerobic group, the expression of PGC-1α in soleus muscle of rats in the resistance group was increased (P<0.05), while the expression of MuRF1 was decreased (P<0.05). Conclusion: Aerobic and resistance exercise can significantly improve muscle contractility, upregulate the expression of PGC-1α/FNDC5, and inhibit the expression of MuRF1, indicating that the molecular mechanisms of aerobic and resistance exercise to improve unloaded muscular atrophy may be related to PGC-1α and MuRF1.
目的: 探究有氧与抗阻运动对去负荷性肌萎缩大鼠比目鱼肌收缩特性及蛋白MuRF1,PGC-1α和FNDC5表达的影响以及可能的分子生物学机制。方法: 将雄性Wistar大鼠随机分为恢复组(CT)、有氧运动组(A)、抗阻运动组(R)和对照组(C),每组6只。对照组不作任何实验处理,其余3组先进行2周尾部悬吊,而后恢复组安静恢复,有氧组与抗阻组进行2周运动干预。运动方案:有氧组大鼠采用65%最大摄氧量(VO2max)对应的跑台速度,60 min/d,5 日/周;抗阻组大鼠负重65%最大有意负重(MVCC)爬梯,3次为一组,共5组,每次休息1 min,每组间歇2 min,5 日/周。最后一次运动后禁食24 h,取比目鱼肌观察组织学变化、测试收缩性能并检测MuRF1,PGC-1α和FNDC5表达情况。结果: 与对照组相比,恢复组大鼠体重、比目鱼肌湿重、肌纤维平均横截面积与肌收缩性能都明显降低(P<0.01),PGC-1α/FNDC5表达明显降低(P<0.01)和MuRF1表达明显升高(P<0.01);与恢复组相比,有氧组和抗阻组大鼠体重、比目鱼肌湿重、肌纤维平均横截面积与肌收缩性能都明显升高(P<0.01),PGC-1α/FNDC5表达明显升高(P<0.01)和MuRF1表达明显降低(P<0.01)。与有氧组相比,抗阻组大鼠比目鱼肌PGC-1α表达显著升高(P<0.05)且MuRF1表达显著降低(P<0.05)。结论: 有氧和抗阻运动可明显提高肌收缩性能,上调PGC-1α/FNDC5的表达,抑制MuRF1蛋白表达,表明有氧与抗阻运动改善去负荷性肌萎缩的分子机制可能与PGC-1α和MuRF1蛋白相关。.
Keywords: aerobics; contractile properties; rats; resistance training; soleus; unloaded.