Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.
J Appl Physiol (1985). 2013 Aug 1;115(3):394-402. doi: 10.1152/japplphysiol.01272.2012. Epub 2013 May 23.
All of the adaptations acquired through physical training are reversible with inactivity. Although significant reductions in maximal oxygen uptake (Vo2max) can be observed within 2 to 4 wk of detraining, the consequences of detraining on the physiology of adipose tissue are poorly known. Our aim was therefore to investigate the effects of discontinuing training (physical detraining) on the metabolism and adipocyte cellularity of rat periepididymal (PE) adipose tissue. Male Wistar rats, aged 6 wk, were divided into three groups and studied for 12 wk under the following conditions: 1) trained (T) throughout the period; 2) detrained (D), trained during the first 8 wk and detrained during the remaining 4 wk; and 3) age-matched sedentary (S). Training consisted of treadmill running sessions (1 h/day, 5 days/wk, 50-60% Vo2max). The PE adipocyte size analysis revealed significant differences between the groups. The adipocyte cross-sectional area (in μm(2)) was significantly larger in D than in the T and S groups (3,474 ± 68.8; 1,945.7 ± 45.6; 2,492.4 ± 49.08, respectively, P < 0.05). Compared with T, the isolated adipose cells (of the D rats) showed a 48% increase in the ability to perform lipogenesis (both basal and maximally insulin-stimulated) and isoproterenol-stimulated lipolysis. No changes were observed with respect to unstimulated lipolysis. A 15% reduction in the proportion of apoptotic adipocytes was observed in groups T and D compared with group S. The gene expression levels of adiponectin and PPAR-gamma were upregulated by factors of 3 and 2 in D vs. S, respectively. PREF-1 gene expression was 3-fold higher in T vs. S. From these results, we hypothesize that adipogenesis was stimulated in group D and accompanied by significant adipocyte hypertrophy and an increase in the lipogenic capacity of the adipocytes. The occurrence of apoptotic nuclei in PE fat cells was reduced in the D and T rats; these results raise the possibility that the adipose tissue changes after detraining are obesogenic.
所有通过体育锻炼获得的适应性变化在不活动时都是可逆的。虽然在停止训练后的 2 到 4 周内可以明显观察到最大摄氧量（Vo2max）的显著降低，但停止训练对脂肪组织生理学的影响知之甚少。因此，我们的目的是研究停止训练（身体脱训）对大鼠附睾周围（PE）脂肪组织代谢和脂肪细胞细胞密度的影响。6 周龄雄性 Wistar 大鼠分为三组，在以下条件下研究 12 周：1）整个时期均进行训练（T）；2）脱训（D），前 8 周进行训练，后 4 周脱训；3）年龄匹配的久坐（S）。训练包括跑步机跑步课程（每天 1 小时，每周 5 天，50-60%Vo2max）。PE 脂肪细胞大小分析显示各组之间存在显著差异。D 组的脂肪细胞横截面积（μm2）明显大于 T 组和 S 组（分别为 3474±68.8；1945.7±45.6；2492.4±49.08，P<0.05）。与 T 组相比，D 组分离的脂肪细胞进行脂肪生成（基础和最大胰岛素刺激）和异丙肾上腺素刺激脂肪分解的能力分别增加了 48%。未观察到未刺激脂肪分解的变化。与 S 组相比，T 组和 D 组的凋亡脂肪细胞比例分别降低了 15%。与 S 组相比，D 组的脂联素和 PPAR-γ基因表达水平分别上调了 3 倍和 2 倍。与 S 组相比，T 组的 Pref-1 基因表达水平升高了 3 倍。从这些结果中，我们假设 D 组的脂肪生成受到刺激，并伴有明显的脂肪细胞肥大和脂肪细胞脂肪生成能力增加。在 D 和 T 组中，PE 脂肪细胞中的凋亡核数量减少；这些结果表明，脱训后脂肪组织的变化可能是肥胖的。
