Cohen L A, Kendall M E, Meschter C, Epstein M A, Reinhardt J, Zang E
American Health Foundation, Valhalla, NY 10595.
In Vivo. 1993 Mar-Apr;7(2):151-8.
In this study, the anti-promoting effect of voluntary (wheel) exercise on 7, 12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumorigenesis was investigated. All rats were fed high fat diets (23% of calories as fat) to mimice the typical western diet. Two doses of DMBA were used to determine if the antipromoting effects of exercise were dependent on the strength of the initiating agent. In addition, tumor estrogen receptors were assayed to determined whether exercise, through an estrogen-suppressing mechanism, selects for estrogen receptor-negative tumors. Female Sprague-Dawley rats were fed a semi-purified 23% fat (corn oil) diet (AIN-76A) and, on day 50 of age administered DMBA by gavage at 5 or 10 mg/rat. Rats were then randomized into 4 groups (n = 30) as follows: 1) low DMBA/sedentary; 2) low DMBA/exercise; 3) high DMBA/-sedentary; and 4) high DMBA/exercise. Active rats were placed in wheel-cage units, which allowed voluntary access to an activity wheel for 133 (low DMBA) and 77 (high DMBA) days, respectively, Sedentary rats were placed in conventional cages. Both active groups exhibited significantly lower total tumor numbers than their sedentary controls: 75 vs 102 (low DMBA) (p < 0.05) and 90 vs 160 (high DMBA) (p < 0.001). Compared to sedentary controls, latency was significantly lengthened in the low but not the high DMBA active groups; multiplicity, in contrast, was significantly decreased in the high, but not the low DMBA exercised group. Exercise had no effect on overall tumor incidence. When segregated into exercise tertiles, total tumor active compared to the least active tertile, particularly in the high DMBA group.(ABSTRACT TRUNCATED AT 250 WORDS)
在本研究中，调查了自愿（转轮）运动对7,12 - 二甲基苯并(a)蒽（DMBA）诱导的乳腺肿瘤发生的抗促进作用。所有大鼠均喂食高脂肪饮食（热量的23%为脂肪）以模拟典型的西方饮食。使用两种剂量的DMBA来确定运动的抗促进作用是否依赖于起始剂的强度。此外，检测肿瘤雌激素受体以确定运动是否通过雌激素抑制机制选择雌激素受体阴性肿瘤。雌性斯普拉格 - 道利大鼠喂食半纯化的23%脂肪（玉米油）饮食（AIN - 76A），并在50日龄时通过灌胃给予DMBA，剂量为5或10 mg/只大鼠。然后将大鼠随机分为4组（每组n = 30），如下：1）低剂量DMBA/ sedentary；2）低剂量DMBA/运动；3）高剂量DMBA/ sedentary；4）高剂量DMBA/运动。活动组大鼠被置于转轮笼装置中，分别允许其自愿使用活动轮133天（低剂量DMBA组）和77天（高剂量DMBA组）， sedentary组大鼠置于常规笼中。两个活动组的肿瘤总数均显著低于其对应的 sedentary对照组：低剂量DMBA组为75个对102个（p < 0.05），高剂量DMBA组为90个对160个（p < 0.001）。与 sedentary对照组相比，低剂量DMBA活动组的潜伏期显著延长，而高剂量DMBA活动组则不然；相反，高剂量DMBA运动组的肿瘤多发性显著降低，而低剂量DMBA运动组则未降低。运动对总体肿瘤发生率没有影响。当按运动三分位数进行分类时，与最不活跃的三分位数相比，活动组的肿瘤总数，特别是在高剂量DMBA组中……（摘要截断于250字）
