Zlatkovic Jovana, Bellman Jakob, Hägg Daniel, Magnusson Mathilda, Ohlsson Claes, DiBona Gerald, Anesten Fredrik, Jansson John-Olov
Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Medicinaregatan 11, 41390, Gothenburg, Sweden.
Sahlgrenska Osteoporosis Centre, Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, 41345, Gothenburg, Sweden.
Pflugers Arch. 2025 Sep 2. doi: 10.1007/s00424-025-03114-3.
Increased weight-bearing load has previously been shown to reduce body weight in obese rodents, primarily by lowering food intake. However, it remains unclear whether increased loading also affects body weight through acute changes in extracellular water. This study aimed to determine whether increased weight-bearing load acutely produces negative sodium and water balances, as indicators of changes in whole-body extracellular sodium and water content. Diet-induced obese (DIO) rats were housed in metabolic cages with free access to hypotonic 0.5% NaCl solution and a low-sodium, high-fat diet. A novel, less traumatic loading method was used, where intra-abdominal capsules implanted two weeks earlier were either filled in vivo with wolfram granulate (Load group) or sham-filled (Control group), resulting in 15% and 2% increases in body weight, respectively. Compared to controls, increased weight-bearing load decreased body weight by 4.2% (95% CI -6.3, -2.0; P = 0.001) and reduced food intake by 1.6 percentage points (95% CI -2.6, -0.6; P = 0.003). No significant differences in sodium or water balance were observed. These findings suggest that load-induced reductions in body weight are not mediated by changes in whole-body extracellular sodium or water content, indicating that fluid homeostasis does not contribute to the homeostatic regulation of body weight.
先前的研究表明，增加负重负荷可降低肥胖啮齿动物的体重，主要是通过减少食物摄入量来实现。然而，增加负荷是否也通过细胞外液的急性变化影响体重仍不清楚。本研究旨在确定增加负重负荷是否会急性导致负钠平衡和水平衡，作为全身细胞外钠和水含量变化的指标。饮食诱导肥胖（DIO）大鼠饲养在代谢笼中，可自由饮用低渗0.5%氯化钠溶液并食用低钠高脂饮食。采用了一种新的、创伤较小的负荷方法，即两周前植入的腹腔内胶囊在体内要么填充钨粒（负荷组），要么进行假填充（对照组），体重分别增加了15%和2%。与对照组相比，增加负重负荷使体重降低了4.2%（95%CI -6.3，-2.0；P = 0.001），食物摄入量减少了1.6个百分点（95%CI -2.6，-0.6；P = 0.003）。未观察到钠平衡或水平衡的显著差异。这些发现表明，负荷诱导的体重减轻不是由全身细胞外钠或水含量的变化介导的，这表明液体稳态对体重的稳态调节没有贡献。
