A Novel Role for Subcutaneous Adipose Tissue in Exercise-Induced Improvements in Glucose Homeostasis.. Mus musculus

Exercise training improves whole body glucose homeostasis through effects largely attributed to adaptations in skeletal muscle; however, training also affects other tissues including adipose tissue. To determine if exercise-induced adaptations to adipose tissue contribute to training-induced improvements in glucose homeostasis, subcutaneous white adipose tissue (scWAT) from trained or sedentary donor mice was transplanted into the visceral cavity of sedentary recipients. Remarkably, nine days post-transplantation, mice receiving trained scWAT had improved glucose tolerance and enhanced insulin sensitivity compared to mice transplanted with sedentary scWAT or sham-treated mice. Mice transplanted with trained scWAT had increased insulin-stimulated glucose uptake in tibialis anterior and soleus muscles and brown adipose tissue, suggesting that the transplanted scWAT exerted endocrine effects. Furthermore, the deleterious effects of high-fat feeding on glucose tolerance and insulin sensitivity were completely reversed if high-fat fed recipient mice were transplanted with trained scWAT. In additional experiments, voluntary exercise training by wheel running for only 11 days resulted in profound changes in scWAT including increased expression of ∼1550 genes involved in numerous cellular functions, including metabolism. Exercise training causes adaptations to scWAT that elicit metabolic improvements in other tissues, demonstrating a previously unrecognized role for adipose tissue in the beneficial effects of exercise on systemic glucose homeostasis. Overall design: Microarray analysis of scWAT obtained from a cohort of mice that were housed in wheel cages for 11 days compared to sedentary control mice.

运动训练可改善全身葡萄糖稳态，其效应主要归因于骨骼肌的适应性改变；然而，训练同时也会影响包括脂肪组织在内的其他组织。为明确运动诱导的脂肪组织适应性改变是否可助力训练介导的葡萄糖稳态改善，研究人员将来自训练组或久坐组供体小鼠的皮下白色脂肪组织（subcutaneous white adipose tissue，scWAT）移植至久坐受体小鼠的腹腔内。值得注意的是，移植后9天，与接受久坐组scWAT移植或假手术处理的小鼠相比，接受训练组scWAT移植的小鼠葡萄糖耐量显著改善，胰岛素敏感性亦明显提升。接受训练组scWAT移植的小鼠，其胫骨前肌、比目鱼肌以及棕色脂肪组织中胰岛素刺激的葡萄糖摄取量均有所升高，这表明移植的scWAT发挥了内分泌效应。此外，若向高脂饮食喂养的受体小鼠移植训练组scWAT，高脂饮食对葡萄糖耐量和胰岛素敏感性造成的有害效应可完全逆转。在额外实验中，仅通过转轮运动开展11天的自愿性训练，即可使scWAT发生显著改变，其中约1550个参与多种细胞功能（包括代谢过程）的基因表达水平上调。运动训练可诱导scWAT产生适应性改变，进而促使其他组织的代谢功能得到改善，这表明脂肪组织在运动对全身葡萄糖稳态的有益影响中，发挥了此前未被认知的作用。整体实验设计：对饲养于转轮笼11天的小鼠队列与久坐对照组小鼠的scWAT开展基因微阵列分析。