Physical actvity in pregnant rat dams reduces mammary tumor formation in offspring
Breast cancer is the most frequently diagnosed cancer and a leading cause of cancer death among women. Lifestyle factors such as physical activity and diet play a role in attenuating the incidence of breast cancer. Current research is beginning to show that exercise during pregnancy can convey long term health benefits to offspring. In light of these studies, the goal of this project was to determine if maternal physical activity during pregnancy could lead to reduced mammary tumor development in female offspring. Towards this goal, female Sprague Dawley rats were divided into two groups, sedentary and exercise, with the exercise group given access to a running wheel during pregnancy and the extent of physical activity was monitored. The resulting female pups from Sedentary and Exercised Dams were weaned at 21 days of age and fed a high fat (HF) diet. None of the pups from either of the groups had access to an exercise wheel at any time. At 6-weeks of age, pups were given a single injection of N-Methyl-N-nitrosourea (MNU) intraperitonealy at 50 mg/kg. The study was conducted for 15-weeks and the developing tumors were palpated and measured with calipers. Endpoint analyses revealed that pups from dams that were allowed physical activity (Exercise) had a substantially lower tumor incidence (42.86%), as compared to pups from sedentary dams (Sedentary), having 100% tumor incidence. Interestingly, Exercise pups and the Sedentary pups had no histological difference in tumor grading. Collectively, these are the first data to demonstrate that short-term physical activity during pregnancy can lead to reduced tumor development in offspring. This study provides an important foundation towards the possibility of developing additional and more effective modes of behavior modification for the prevention of cancers.
Camarillo, Purdue University.
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