Nucleoprotein supplementation enhances the recovery of rat soleus mass with reloading after hindlimb unloading-induced atrophy via myonuclei accretion and increased protein synthesis
Nucleoprotein supplementation enhances the recovery of rat soleus mass with reloading after hindlimb unloading-induced atrophy via myonuclei accretion and increased protein synthesis
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DOI：
10.1016/j.nutres.2016.10.007
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发表时间：
2016-12-01
影响因子：
4.5
通讯作者：
Fujino, Hidemi
中科院分区：
文献类型：
--
作者：
Nakanishi, Ryosuke;Hirayama, Yusuke;Fujino, Hidemi
后肢去负荷导致肌肉萎缩，一段时间的再负荷已被证明可以部分恢复失去的肌肉质量。肌肉质量恢复的两个机制是蛋白质合成途径的激活和肌核数量的增加。额外的肌核由卫星细胞提供，卫星细胞被与肌肉重新加载相关的机械应力激活，并最终并入肌纤维。运动时补充氨基酸也可以通过增强蛋白质合成来增加骨骼肌质量，补充核苷酸可以促进细胞周期活性。因此，我们假设补充核蛋白，氨基酸和核苷酸的组合，将在更大程度上提高肌肉质量的恢复比卸载一段时间后单独重新加载。成年大鼠分为4组：对照组、后肢卸载组（HU; 14天）、后肢卸载后再加载组（HUR）和后肢卸载后再加载加核蛋白补充组（HUR + NP）。与HUR组相比，HUR + NP组比目鱼肌和纤维横截面积更大，磷酸化rpS6水平更高，肌核和肌细胞生成素阳性细胞数量更高。这些结果表明，核蛋白补充剂具有协同作用，通过rpS6激活和卫星细胞分化和纳入肌纤维的卸载一段时间后，在恢复骨骼肌性能的再加载。因此，这种补充剂可能是一种有效的治疗方案，包括在各种肌肉萎缩状况的康复策略中，如衰老，癌症恶病质，肌肉萎缩症，卧床休息和石膏固定。(C)2016 Elsevier Inc. All rights reserved.
Hindlimb unloading results in muscle atrophy and a period of reloading has been shown to partially recover the lost muscle mass. Two of the mechanisms involved in this recovery of muscle mass are the activation of protein synthesis pathways and an increase in myonuclei number. The additional myonuclei are provided by satellite cells that are activated by the mechanical stress associated with the reloading of the muscles and eventually incorporated into the muscle fibers. Amino acid supplementation with exercise also can increase skeletal muscle mass through enhancement of protein synthesis and nucleotide supplements can promote cell cycle activity. Therefore, we hypothesized that nucleoprotein supplementation, a combination of amino acids and nucleotides, would enhance the recovery of muscle mass to a greater extent than reloading alone after a period of unloading. Adult rats were assigned to 4 groups: control, hindlimb unloaded (HU; 14 days), reloaded (5 days) after hindlimb unloading (HUR), and reloaded after hindlimb unloading with nucleoprotein supplementation (HUR + NP). Compared with the HUR group, the HUR + NP group had larger soleus muscles and fiber cross-sectional areas, higher levels of phosphorylated rpS6, and higher numbers of myonuclei and myogenin-positive cells. These results suggest that nucleoprotein supplementation has a synergistic effect with reloading in recovering skeletal muscle properties after a period of unloading via rpS6 activation and satellite cell differentiation and incorporation into the muscle fibers. Therefore, this supplement maybe an effective therapeutic regimen to include in rehabilitative strategies for a variety of muscle wasting conditions such as aging, cancer cachexia, muscular dystrophy, bed rest, and cast immobilization. (C) 2016 Elsevier Inc. All rights reserved.