Caloric restriction (CR) can improve health, but the benefits are age-dependant. We studied effects of ten-week 30 % CR on skeletal muscles of adult (7-month old) and old (24-month old) C57BL/6 J mice. Old mice were heavier than adult mice (36.1 ± 4.0 g versus 32.9 ± 2.3 g, p < 0.05, respectively), but lost more weight (34.7 ± 6.0 % versus 23.9 ± 3.3 %, p < 0.001, respectively) during CR. Old mice did not differ from adult mice in extent of hind-limb muscle wasting or improvement in glucose tolerance after CR. Ageing and CR had an additive effect on increase in percentage of type 1 fibres in the soleus (SOL) muscle. CR was associated with greater atrophy of fast-twitch extensor digitorum longus (EDL) compared to slow-twitch SOL muscle. Old mice showed reduced gene expression of lysosomal markers, p62 and LC3B, while CR tended to upregulate the proteolysis genes. CR was also associated with increase in specific force of EDL muscle, but did not affect it in SOL muscle. In summary, ten-week CR induces only limited improvements in skeletal muscle function, but leads to significant muscle wasting and weakness in both adult and old mice.

热量限制 (CR) 可以改善健康，但其益处取决于年龄。我们研究了 10 周 30% CR 对成年（7 个月大）和大（24 个月大）C57BL/6 J 小鼠骨骼肌的影响。老年小鼠比成年小鼠重（分别为 36.1 ± 4.0 克和 32.9 ± 2.3 克，p < 0.05），但体重减轻更多（34.7 ± 6.0 % 对 23.9 ± 3.3 %，p< 0.001，分别）在 CR 期间。老年小鼠在 CR 后后肢肌肉萎缩或葡萄糖耐量改善的程度与成年小鼠没有区别。衰老和 CR 对比目鱼肌 (SOL) 肌肉中 1 型纤维百分比的增加具有累加作用。与慢速收缩 SOL 肌肉相比，CR 与快收缩趾长伸肌 (EDL) 的更大程度的萎缩有关。老年小鼠显示溶酶体标志物 p62 和 LC3B 的基因表达降低，而 CR 倾向于上调蛋白水解基因。CR 也与 EDL 肌肉的比力增加有关，但在 SOL 肌肉中没有影响。总之，10 周的 CR 仅诱导骨骼肌功能的有限改善，但会导致成年小鼠和老年小鼠的显着肌肉萎缩和虚弱。