Department of Exercise Science, University of South Carolina, Columbia, SC.
Department of Physical Therapy, College of Health Professions, The University of Tennessee Health Sciences Center, Memphis, TN.
Med Sci Sports Exerc. 2020 Nov;52(11):2320-2330. doi: 10.1249/MSS.0000000000002393.
Cancer-related fatigue and muscle wasting have received significant attention over the last few decades with the goal of establishing interventions that can improve cancer patient life quality and survival. Increased physical activity has shown to reduce cancer-associated fatigue and has been proposed as a promising therapeutic to attenuate cancer-induced wasting. However, significant gaps remain in our understanding of how physical activity affects the compositional and functional changes that initiate muscle wasting. The purpose of the current study was to determine the effect of wheel exercise on body composition and functional indices of cancer cachexia before the development of significant wasting.
Thirteen-week-old male Apc (MIN) and C57BL/6 (B6) mice were given free wheel access (W) or a locked wheel (Sed) for 5 wk.
Wheel activity was reduced in the MIN compared with B6; however, wheel access increased complex II expression in isolated skeletal muscle mitochondria regardless of genotype. Wheel access had no effect on tumor burden or plasma interleukin-6 in the MIN. MIN-W increased body weight and lean mass compared with MIN-Sed, and there was a direct correlation between wheel distance and lean mass change. MIN-W increased grip strength and treadmill time to fatigue compared with MIN-Sed. Within MIN-W mice, skeletal muscle fatigability was only improved in high runners (>60 min·d).
Our results suggest that there were therapeutic benefits of increased activity related to body composition, behavior, and whole-body function that were not dependent on exercise duration; however, there was an exercise threshold needed to improve skeletal muscle fatigability in tumor-bearing mice. Interestingly, wheel access was able to improve compositional and functional outcomes without mitigating tumor number or size.
在过去几十年中，癌症相关性疲劳和肌肉减少症受到了广泛关注，其目的是建立能够改善癌症患者生活质量和生存率的干预措施。增加身体活动已被证明可以减轻癌症相关性疲劳，并被提出作为一种有前途的治疗方法来减轻癌症引起的消瘦。然而，我们对身体活动如何影响引发肌肉减少症的组成和功能变化的理解仍存在很大差距。本研究的目的是确定在发生明显消瘦之前，轮式运动对癌症恶病质的身体成分和功能指标的影响。
13 周龄雄性 Apc（MIN）和 C57BL/6（B6）小鼠给予自由轮式活动（W）或锁定轮式活动（Sed）5 周。
MIN 中的轮式活动减少，但无论基因型如何，轮式活动均可增加分离骨骼肌线粒体中的复合物 II 表达。轮式活动对 MIN 中的肿瘤负担或血浆白细胞介素-6 没有影响。MIN-W 组的体重和瘦体重均高于 MIN-Sed 组，并且轮距与瘦体重变化之间存在直接相关性。MIN-W 组的握力和跑步机疲劳时间均高于 MIN-Sed 组。在 MIN-W 组中，只有高跑步者（>60 min·d）的骨骼肌疲劳性得到改善。
我们的结果表明，增加活动与身体成分、行为和全身功能相关的治疗益处与运动时间无关；然而，在荷瘤小鼠中，改善骨骼肌疲劳性需要运动阈值。有趣的是，轮式活动无需减轻肿瘤数量或大小，就能改善成分和功能结果。
