Department of Physical Therapy, School of Rehabilitation Sciences, Health Sciences University of Hokkaido, Tobetsu 061-0293, Japan.
Graduate School of Sport and Health Science, Ritsumeikan University, Kusatsu 525-8577, Japan.
Nutrients. 2024 Jul 23;16(15):2390. doi: 10.3390/nu16152390.
Leucine is a branched-chain amino acid that is present in protein, and it is an essential factor in activating the mechanistic target of the rapamycin complex 1 signaling pathway and increasing muscle protein synthesis. However, the loss of digestive function after total gastrectomy leads to impaired protein absorption, potentially failing to stimulate muscle protein synthesis. Therefore, this study aimed to investigate whether muscle protein synthesis is enhanced by oral skim milk administration after total gastrectomy. Male Sprague Dawley rats were divided into total gastrectomy (TG) and sham surgery (S) groups. After five weeks postoperatively, we orally administered skim milk to achieve 3.1 g protein/kg body weight and collected blood and gastrocnemius muscle. The gastrocnemius muscle weight was significantly lower in the TG group than in the S group ( < 0.05). The increase in plasma leucine concentration was significantly lower in the TG group than in the S group ( < 0.05). The skeletal muscle protein synthesis and the phosphorylation of p70S6K and 4E-BP1 showed a similar increase in both groups. Even after TG, muscle protein synthesis was stimulated by consuming skim milk, accompanied by a sufficient rise in plasma leucine concentration.
亮氨酸是一种存在于蛋白质中的支链氨基酸，它是激活雷帕霉素靶蛋白复合物 1 信号通路和增加肌肉蛋白质合成的必需因素。然而，全胃切除术后消化功能的丧失导致蛋白质吸收受损，可能无法刺激肌肉蛋白质合成。因此，本研究旨在探讨全胃切除术后口服脱脂牛奶是否能增强肌肉蛋白质合成。雄性 Sprague Dawley 大鼠分为全胃切除（TG）和假手术（S）组。术后五周，我们经口给予脱脂牛奶，使体重达到 3.1 g 蛋白质/kg，采集血液和比目鱼肌。TG 组的比目鱼肌重量明显低于 S 组（<0.05）。TG 组的血浆亮氨酸浓度升高明显低于 S 组（<0.05）。两组的骨骼肌蛋白质合成和 p70S6K 和 4E-BP1 的磷酸化均呈相似增加。即使在 TG 后，摄入脱脂牛奶也能刺激肌肉蛋白质合成，并伴有血浆亮氨酸浓度的充分升高。
