MacNeil B, Hoffman-Goetz L
Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Ontario, Canada.
Med Sci Sports Exerc. 1993 Aug;25(8):922-8.
Exercise has been demonstrated to reduce experimental tumor formation in rodents when the exercise is present during the tumor initiation or promotion phases. This study evaluated whether exercise influenced the process of tumor metastasis and subsequent growth in a secondary implant site. Male C3H mice remained sedentary, were given free access to running wheels, ran on a treadmill (15 m.min-1, 30 min.d-1), or walked on a treadmill (5 m.min-1, 5 min.d-1)(N = 20/group). Following 9 wk of this protocol, exercise was discontinued. At this time all animals received a tumor cell dose (CIRAS 1, 3 x 10(5)) i.v., and remained sedentary until sacrificed 3 wk later. Splenic natural killer (NK) cell activity was elevated in the wheel running mice compared with sedentary controls 3 wk after cessation of exercise (F(3,74) = 6.266, P < 0.002). Exercised mice displayed lower tumor cell retention in the lungs relative to nonexercised mice (F(1,37) = 6.593, P < 0.02). Tumor incidence was not different across activity groups whereas tumor multiplicity was higher in mice that had been previously exposed to exercise. (However, it should be noted that the significant exercise-tumor effect was due to a small number of exercised mice with extreme multiplicity, > 200 foci/lung.) More extensive tumor colony formation was present in wheel-trained mice that displayed the greatest volumes of daily running. The results from this study suggest that exercise was able to augment natural immune cytotoxic function for up to 3 wk after cessation of activity. However, this augmentation of natural immune function was not associated with reduced tumor incidence in the exercised animals.
当运动出现在肿瘤起始或促进阶段时，已证明运动可减少啮齿动物实验性肿瘤的形成。本研究评估了运动是否会影响肿瘤转移过程以及在二次植入部位的后续生长。雄性C3H小鼠保持 sedentary（久坐不动）、可自由使用跑轮、在跑步机上跑步（15米/分钟，每天30分钟）或在跑步机上行走（5米/分钟，每天5分钟）（每组N = 20只）。按照此方案进行9周后，停止运动。此时，所有动物静脉注射肿瘤细胞剂量（CIRAS 1，3×10⁵），并保持 sedentary 状态直至3周后处死。与久坐对照组相比，在停止运动3周后，跑轮运动小鼠的脾脏自然杀伤（NK）细胞活性升高（F(3,74) = 6.266，P < 0.002）。与未运动的小鼠相比，运动小鼠肺部的肿瘤细胞滞留率较低（F(1,37) = 6.593，P < 0.02）。各活动组的肿瘤发生率无差异，而先前接受运动的小鼠肿瘤 multiplicity（多发性）更高。（然而，应注意的是，显著的运动 - 肿瘤效应是由于少数运动小鼠具有极高的多发性，> 200个病灶/肺。）在显示每日跑步量最大的跑轮训练小鼠中，存在更广泛的肿瘤集落形成。本研究结果表明，运动能够在停止活动后长达3周的时间内增强自然免疫细胞毒性功能。然而，这种自然免疫功能的增强与运动动物肿瘤发生率的降低无关。
