Effects of lifelong exercise training on mammary tumorigenesis induced by MNU in female Sprague-Dawley rats.
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.
Department of Veterinary Sciences, School of Agrarian and Veterinary Sciences, University of Trás-os-Montes and Alto Douro, UTAD, 5001-911, Vila Real, Portugal. anafaustino.faustino@sapo.pt.|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. anafaustino.faustino@sapo.pt.|Animal and Veterinary Research Center (CECAV), University of Trás-os-Montes and Alto Douro, UTAD, 5001-911, Vila Real, Portugal. anafaustino.faustino@sapo.pt.|Department of Chemistry, Organic Chemistry, Natural Products and Foodstuffs (QOPNA), Mass Spectrometry Center, University of Aveiro, 3810-193, Aveiro, Portugal. anafaustino.faustino@sapo.pt.
Ana I
AI
Faustino-Rocha
Department of Veterinary Sciences, School of Agrarian and Veterinary Sciences, University of Trás-os-Montes and Alto Douro, UTAD, 5001-911, Vila Real, Portugal.|Animal and Veterinary Research Center (CECAV), University of Trás-os-Montes and Alto Douro, UTAD, 5001-911, Vila Real, Portugal.
Adelina
A
Gama
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.
Paula A
PA
Oliveira
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.|Área de Patología, Decanato de Ciencias Veterinarias, Universidad Centroccidental "Lisandro Alvarado", UCLA, 3023, Lara, Venezuela.
Antonieta
A
Alvarado
Institute of Research and Advanced Training in Health Sciences and Technologies (IINFACTS), CESPU, 4585-116, Gandra, Portugal.|Faculty of Sports, Research Centre in Physical Activity, Health and Leisure (CIAFEL), University of Porto, 4200-450, Porto, Portugal.
Maria J
MJ
Neuparth
Department of Chemistry, Organic Chemistry, Natural Products and Foodstuffs (QOPNA), Mass Spectrometry Center, University of Aveiro, 3810-193, Aveiro, Portugal.
Rita
R
Ferreira
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.
Mário
M
Ginja
D000818:Animals; D063646:Carcinogenesis; D047628:Estrogen Receptor alpha / Q000032:analysis; D005260:Female; D015674:Mammary Neoplasms, Animal / Q000453:epidemiology* / Q000473:pathology; D010805:Physical Conditioning, Animal; D017207:Rats, Sprague-Dawley
D047628:Estrogen Receptor alpha
Estradiol; Estrogen receptors; Exercise; MNU; Mammary tumors