Weber Ramona E, Schulze Kiana M, Kenney Nathan J, Scheuermann Britton C, Kunkel Olivia N, Ade Carl J, Musch Timothy I, Behnke Brad J, Poole David C
Department of Kinesiology, Kansas State University Manhattan, KS 66506, USA.
Department of Anatomy and Physiology, Kansas State University Manhattan, KS 66506, USA.
Am J Cancer Res. 2025 Feb 15;15(2):487-500. doi: 10.62347/QCCZ2316. eCollection 2025.
Breast cancer patients' maximal O uptake (V̇Omax) values average 60-80% of age-predicted values which is often attributed to adjuvant therapy rather than risk factors, comorbidities, or the tumor and associated factors (e.g., pro-inflammatory cytokines). It is crucial to understand the physiological mechanisms behind exercise intolerance in breast cancer patients to enhance targeted interventions; however, the effect of breast cancer, as an isolated condition on V̇Omax, exercise tolerance, and resting cardiac function has not been investigated. We hypothesized that breast cancer, in the absence of underlying conditions or chemotherapy, would lower V̇Omax, exercise tolerance, and cardiac function in proportion to tumor mass. Female Fischer-344 rats (6-8 months, n = 8) were acclimatized to treadmill running for 5 days at 25 m/min for 5 min/day. To measure V̇Omax, rats were placed within a plexiglass metabolic chamber connected to CO and O analyzers. Tests began at 25 m/min and increased (5 m/min) until exhaustion. Cardiac function was determined by echocardiography before rats received a mammary intraductal injection of rat adenocarcinoma cells (MATBIII, 6 × 10 in 50 µl saline). Tumor growth was monitored daily and ~7 days following palpation (24 days post-injection), V̇Omax and echocardiography measurements were repeated. Tumor mass and volume were 2.1 ± 0.6 g and 1685 ± 428 (range 256-3749) mm, respectively. Body mass (217 ± 6 vs 218 ± 6 g), V̇Omax (72.1 ± 2.7 vs 70.0 ± 2.8 ml/kg·min; P > 0.05), and all measures of cardiac function were unchanged following tumor formation, with no significant correlation between tumor mass and V̇Omax (P > 0.05). However, time to exhaustion (376 ± 20 vs 297 ± 25 s), final treadmill speed (48 ± 1 vs 42 ± 2 m/s), distance run (209 ± 16 vs 152 ± 18 m), and total work (45 ± 3 vs 32 ± 4 m·kg) were significantly reduced with tumor bearing. Contrary to our hypothesis, breast cancer did not affect V̇Omax or cardiac function, but reduced exercise tolerance.
乳腺癌患者的最大摄氧量（V̇Omax）值平均为年龄预测值的60 - 80%，这通常归因于辅助治疗，而非风险因素、合并症或肿瘤及相关因素（如促炎细胞因子）。了解乳腺癌患者运动不耐受背后的生理机制对于加强针对性干预至关重要；然而，乳腺癌作为一种独立病症对V̇Omax、运动耐力和静息心功能的影响尚未得到研究。我们假设，在没有基础疾病或化疗的情况下，乳腺癌会按肿瘤大小成比例降低V̇Omax、运动耐力和心功能。雌性Fischer - 344大鼠（约6 - 8个月，n = 8）以25米/分钟速度适应跑步机跑步5天，每天跑5分钟。为测量V̇Omax，将大鼠置于连接CO和O分析仪的有机玻璃代谢室中。测试从25米/分钟开始，然后以（5米/分钟）递增直至大鼠精疲力竭。在大鼠接受乳腺导管内注射大鼠腺癌细胞（MATBIII，50微升盐水中含6×10个）前，通过超声心动图测定心功能。每天监测肿瘤生长情况，在触诊后约7天（注射后约24天），重复测量V̇Omax和超声心动图。肿瘤质量和体积分别为2.1±0.6克和1685±428（范围256 - 3749）立方毫米。肿瘤形成后，体重（217±6对218±6克）、V̇Omax（72.1±2.7对70.0±2.8毫升/千克·分钟；P>0.05）以及所有心功能指标均未改变，肿瘤质量与V̇Omax之间无显著相关性（P>0.05）。然而，荷瘤大鼠的运动至疲劳时间（376±20对297±25秒）、最终跑步机速度（48±1对42±2米/秒）、跑步距离（209±16对152±18米）和总功（45±3对32±4米·千克）均显著降低。与我们的假设相反，乳腺癌并未影响V̇Omax或心功能，但降低了运动耐力。
