Weight-bearing exercise prevents skeletal muscle atrophy in ovariectomized rats

Skeletal muscle atrophy (SMA) is a dominant symptom induced by estrogen deficiency which can lead to severe health problems of postmenopausal women. Furthermore, estrogen deficiency has severely compromised the maintenance of muscle stem cells as well as impairs self-renewal and differentiation into muscle fibers. Resistance training is commonly considered as a positive and useful intervention in accelerating the rate of muscle growth. As one of the resistance training, whether the weight-bearing exercise can alleviate SMA induced by estrogen deficiency has not been investigated. The rats were divided into 3 groups randomly: sham group, ovariectomized (OVX) group, and weight-bearing exercise (WBE) therapeutic group. The weight that rats were loaded was 35% of their body weight, and the rats were trained by treadmill training (5° slope, 20 m/min, 30 min/day, 6 days/week) for 8 weeks. After training, the quality and strength of skeletal muscle of the WBE rats were improved; meanwhile, the cross-sectional areas of the skeletal muscle were also increased. Moreover, the WBE activated Akt significantly, upregulated the expression of mTOR, and downregulated the expression of MSTN and its receptor ActRIIB and FoxO1, respectively. The SMA phenomena of rats which induced by estrogen deficiency were prevented effectively via WBE, and the MSTN/Akt/mTOR and FoxO1 signaling pathway may be the predominant way in this improvement.