The effect of calorie restriction and exercise on cell proliferation rates in female mice

Abstract

Calorie restriction (CR) inhibits tumor growth, which is associated with reduced cell proliferation in tumorigenic tissues. Exercise also slows tumor growth, however, the effect of exercise on cell proliferation has not been systematically investigated. Accordingly, the purpose of this study was to compare the effects of voluntary wheel running (EX) and CR on cell proliferation in tumorigenic tissues. In this study, mice were randomized into four groups; ad libitum‐fed, sedentary (AL/SED), ad libitum‐fed, exercise (AL/EX), pair‐fed to AL/SED, exercise (PF/EX) or calorie restricted, sedentary (CR/SED). We found that cell proliferation was significantly lower in liver tissue, skin epidermis and splenic T‐cells in CR/SED as compared to AL/SED. In contrast, cell proliferation was not different in any of the tissues in either of the exercise groups compared to AL/SED, despite higher food intake and energy expenditure in AL/EX and lower body weight in PF/EX. In addition, serum IGF‐1 was significantly lower in CR/SED compared to AL/SED while there was no difference in either exercise group. We conclude that the effect of CR on cell proliferation in tumorigenic tissues cannot be mimicked by exercise despite its associated increase in energy expenditure and comparable reduction in body weight. These data have implications for understanding the mechanism by which CR and EX inhibit tumor growth and promote longevity.Grant Funding Source: NIH