Department of Medical Physiology, Faculty of Medicine, Universitas Indonesia, Jakarta 10430, Indonesia.
Master Program in Biomedical Sciences, Faculty of Medicine, Universitas Indonesia, Jakarta 10430, Indonesia.
Biomed Res Int. 2018 Dec 27;2018:4708287. doi: 10.1155/2018/4708287. eCollection 2018.
Recently, high-intensity intermittent training (HIIT) appears to have the same beneficial effects or even superior to those of continuous moderate-intensity training (CMIT) on body fat mass reduction. Exercise may induce myokine secretion such as irisin, which plays a role as a mediator of beiging process, and thus might contribute as treatment of obesity. However, the effects of those exercise formulas on irisin level changes as beiging agent are not known. In addition, metabolic states may affect the irisin responses to those exercise formulas. Therefore, this study was aimed to determine the different effects of exercises using HIIT and CMIT on circulating and tissue irisin levels in normal and abnormal metabolic conditions (obese).
Sixteen male Sprague-Dawley rats (8 weeks of age) were randomized to 4 groups according to training regimens (HIIT and CMIT) and metabolic conditions (normal and abnormal/obese). The groups are (1) HIIT on normal metabolic (n=4), (2) CMIT on normal metabolic (n=4), (3) HIIT on abnormal metabolic (n=4), and (4) CMIT on abnormal metabolic (n=4). Abnormal metabolic condition was induced with high fat diet (19% fat) for 8 weeks in obese rats. Irisin levels in serum, skeletal muscle, and white adipose tissue were evaluated by ELISA.
Serum irisin levels were shown significantly higher in normal metabolic compared to abnormal metabolic condition (P<0.001). The effect of interaction between metabolic condition and exercise formula was found (P<0.01) on adipose irisin levels. The effect of HIIT was shown significantly more effective on adipose irisin levels, compared with CMIT in abnormal metabolic conditions. However, no significant differences of skeletal muscle irisin levels were found in both normal and abnormal metabolic subjects (P>0.05). Regarding exercise formula, no different effects were found between HIIT and CMIT on skeletal muscle irisin levels in both metabolic conditions (P>0.05). The similar findings were observed in serum irisin levels (P>0.05).
The exercise effects in abnormal metabolic condition might be more adaptable in maintaining the irisin levels in skeletal muscle and induce the irisin uptake from circulation into adipose tissue. In addition, HIIT might be more involved to induce irisin uptake into adipose tissue; thus it might have the significant role in beiging process. However, further research about how the HIIT formula affects the regulation mechanisms of irisin uptake into adipose tissue is still warranted.
最近，高强度间歇训练（HIIT）似乎在减少体脂肪质量方面具有与持续中等强度训练（CMIT）相同的有益效果，甚至更优。运动可能会诱导肌因子（如鸢尾素）的分泌，其作为褐色化过程的介质发挥作用，因此可能作为肥胖症的治疗方法。然而，尚不清楚这些运动方案作为褐色化剂对鸢尾素水平变化的影响。此外，代谢状态可能会影响鸢尾素对这些运动方案的反应。因此，本研究旨在确定 HIIT 和 CMIT 对正常和异常代谢状态（肥胖）中循环和组织鸢尾素水平的不同影响。
将 16 只 8 周龄雄性 Sprague-Dawley 大鼠随机分为 4 组，根据训练方案（HIIT 和 CMIT）和代谢状态（正常和异常/肥胖）分组。各组为（1）正常代谢的 HIIT（n=4），（2）正常代谢的 CMIT（n=4），（3）异常代谢的 HIIT（n=4）和（4）异常代谢的 CMIT（n=4）。肥胖大鼠用高脂肪饮食（19%脂肪）诱导 8 周以建立异常代谢状态。通过 ELISA 评估血清、骨骼肌和白色脂肪组织中的鸢尾素水平。
与异常代谢状态相比，正常代谢状态下血清鸢尾素水平显著升高（P<0.001）。还发现代谢状态和运动方案之间的交互作用的影响（P<0.01）对脂肪组织鸢尾素水平有影响。与 CMIT 相比，HIIT 在异常代谢状态下对脂肪组织鸢尾素水平的影响更显著。然而，在正常和异常代谢受试者中均未发现骨骼肌鸢尾素水平的显著差异（P>0.05）。关于运动方案，在两种代谢状态下，HIIT 和 CMIT 对骨骼肌鸢尾素水平均无不同影响（P>0.05）。在血清鸢尾素水平方面也观察到类似的结果（P>0.05）。
异常代谢状态下的运动效应可能更适合维持骨骼肌中的鸢尾素水平，并将鸢尾素从循环中摄取到脂肪组织中。此外，HIIT 可能更有助于诱导鸢尾素摄取到脂肪组织中；因此，它可能在褐色化过程中具有重要作用。然而，仍需要进一步研究 HIIT 方案如何影响鸢尾素摄取到脂肪组织的调节机制。
