Faustino-Rocha Ana I, Gama Adelina, Oliveira Paula A, Alvarado Antonieta, Neuparth Maria J, Ferreira Rita, Ginja Mário
Department of Veterinary Sciences, School of Agrarian and Veterinary Sciences, University of Trás-os-Montes and Alto Douro, UTAD, 5001-911, Vila Real, Portugal.
Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes and Alto Douro, UTAD, 5001-911, Vila Real, Portugal.
Clin Exp Med. 2017 May;17(2):151-160. doi: 10.1007/s10238-016-0419-0. Epub 2016 Apr 19.
Breast cancer is the most common malignancy in women worldwide. Several studies have suggested that exercise training may decrease the risk of breast cancer development. This study aimed to evaluate the effects of long-term exercise training on mammary tumorigenesis in an animal model of mammary cancer. Fifty female Sprague-Dawley rats were randomly divided into four groups: MNU sedentary, MNU exercised, control sedentary and control exercised. Animals from MNU groups received an intraperitoneal administration of N-methyl-N-nitrosourea (MNU). Animals were exercised on a treadmill during 35 weeks. When animals were killed, blood samples were collected to determine the hematocrit and to perform the biochemical analysis. Mammary tumors were collected and histologically evaluated; the expression of ERs α and β was evaluated in tumor sections by immunohistochemistry. All survived animals from both MNU groups developed mammary tumors. The number of mammary tumors (p > 0.05) and lesions (p = 0.056) was lower in MNU exercised than in MNU sedentary animals. MNU exercised animals showed lower number of malignant lesions than MNU sedentary animals (p = 0.020). C-reactive protein serum concentration was lower in exercised animals; however, the levels of 17-β estradiol were higher in exercised animals. Tumors from exercised animals exhibited higher expression of ER α than tumors from sedentary animals (p < 0.05). This study analyzes the impact of the longest exercise training protocol on mammary tumorigenesis ever performed. We concluded that the lifelong endurance training has beneficial effects on mammary tumorigenesis in female rats (reduced the inflammation, the number of mammary tumors and lesions, and histological grade of malignancy). Additionally, the mammary tumors from MNU exercised group exhibited higher immunoexpression of ER α that is an indicator of well-differentiated tumors and better response to hormone therapy.
乳腺癌是全球女性中最常见的恶性肿瘤。多项研究表明，运动训练可能会降低患乳腺癌的风险。本研究旨在评估长期运动训练对乳腺癌动物模型中乳腺肿瘤发生的影响。将50只雌性斯普拉格-道利大鼠随机分为四组：MNU静息组、MNU运动组、对照静息组和对照运动组。MNU组的动物腹腔注射N-甲基-N-亚硝基脲（MNU）。动物在跑步机上运动35周。处死动物时，采集血样以测定血细胞比容并进行生化分析。收集乳腺肿瘤并进行组织学评估；通过免疫组织化学评估肿瘤切片中雌激素受体α和β的表达。两个MNU组的所有存活动物均发生了乳腺肿瘤。MNU运动组的乳腺肿瘤数量（p>0.05）和病变数量（p=0.056）低于MNU静息组动物。MNU运动组动物的恶性病变数量低于MNU静息组动物（p=0.020）。运动动物的血清C反应蛋白浓度较低；然而，运动动物的17-β雌二醇水平较高。运动动物的肿瘤比静息动物的肿瘤表现出更高的雌激素受体α表达（p<0.05）。本研究分析了有史以来最长的运动训练方案对乳腺肿瘤发生的影响。我们得出结论，终身耐力训练对雌性大鼠的乳腺肿瘤发生具有有益作用（减少炎症、乳腺肿瘤和病变数量以及恶性组织学分级）。此外，MNU运动组的乳腺肿瘤表现出更高的雌激素受体α免疫表达，这是肿瘤分化良好和对激素治疗反应更好的指标。
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