Abstract

Fasting improves health, but can cause muscle weakness. We assessed body composition in 21-week old males of Berlin high (BEH+/+) and Berlin low (BEL) strains after two bouts of 48-h or 40-h of fasting with 5-day refeeding in between, respectively. BEH+/+ mice tended to loose less weight than BEL in bout 1 and 2 (16.0 ± 2.7 versus 23.5 ± 2.9%, p < 0.001 and 17.1 ± 3.4 versus 20.4 ± 3.4%, p = 0.17, respectively). In spite of greater serum IGF-1 and body fat levels, BEH+/+ mice showed more severe muscle atrophy, but less marked liver wasting and fat depletion than BEL mice. BEH+/+ mice also showed smaller increases in expression of p62, Atrogin-1, and Mstn genes in skeletal muscles. In summary, BEL mice show resistance to fasting-induced muscle wasting in spite of low serum IGF-1 levels and high expression of genes associated with muscle atrophy.

摘要

禁食可以改善健康，但会导致肌肉无力。我们评估了柏林高 (BEH+/+) 和柏林低 (BEL) 品系 21 周龄雄性的身体成分，分别在禁食 48 小时或 40 小时两次，中间再喂食 5 天。在第 1 轮和第 2 轮中，BEH+/+ 小鼠的体重往往比 BEL 减轻（分别为 16.0 ± 2.7 对 23.5 ± 2.9%，p  < 0.001 和 17.1 ± 3.4 对 20.4 ± 3.4%，p  = 0.17）。尽管血清 IGF-1 和体脂水平更高，但与 BEL 小鼠相比，BEH+/+ 小鼠表现出更严重的肌肉萎缩，但肝脏消耗和脂肪消耗较少。BEH+/+ 小鼠也显示p62、Atrogin-1和Mstn表达的较小增加骨骼肌中的基因。总之，尽管血清 IGF-1 水平低且与肌肉萎缩相关的基因表达高，但 BEL 小鼠对禁食诱导的肌肉萎缩表现出抵抗力。