EFFECTS OF LOW INTENSITY TREADMILL EXERCISE ON MUSCLE WASTING IN THE MALE TUMOR BEARING MOUSE

Abstract

Louisa Tichy, Jason T. Brantley, Traci L. Parry. University of North Carolina at Greensboro, Greensboro, NC. Background: Cancer cachexia is a multifactorial, metabolic wasting syndrome that is responsible for up to one-third of deaths in cancer patients. While research is growing, there are no clear diagnostic criteria and cancer cachexia remains an untreated condition. Current research shows that exercise interventions could have a positive impact on cancer cachexia by slowing its development. Questions remain regarding the most effective time, duration, and intensity of exercise as a preventative intervention against cancer cachexia. Purpose: The purpose of this study was to determine if low intensity treadmill exercise can act as a protective measure and treatment intervention against cancer-mediated muscle wasting in male mice. Methods: Male LC3 Tg+ mice and WT mice were randomly separated into four groups, sedentary non-tumor bearing (SED+NT), sedentary tumor bearing (SED+T), treadmill exercise non-tumor bearing (Low+NT), and treadmill exercise tumor bearing (Low+T). Mice were injected with tumor cells (T group; 5x105 LLC cells in flank) or remained non-tumor (NT) for 4 weeks. During the 4 weeks, mice underwent a low-intensity treadmill exercise training protocol (Low) or remained sedentary (SED). To examine the protective effects of exercise, grip strength, echocardiography and tumor growth evaluations were taken at baseline and the 4-week time points. Results: Sedentary tumor bearing mice (SED+T) exhibited the worst skeletal muscle function (grip strength) and cardiac function (fractional shortening) compared to all other groups. Low intensity treadmill appeared to protect the musculature since exercised tumor bearing mice (Low+T) showed a preservation of both grip strength and fractional shortening compared to their sedentary counterparts (SED+T). Additionally, treadmill exercise (Low+T) resulted in smaller tumor mass and volume (p=0.066) compared to the SED+T group. Conclusion: Low-intensity treadmill exercise shows potential to preserve skeletal and cardiac muscle function, as well as stunt tumor growth. Therefore, low-intensity treadmill exercise may be an effective, affordable, and accessible treatment intervention for cancer patients. This information is crucial in understanding the significance of exercise in cancer patients and elucidating the importance of timing and intensity of exercise as a protective measure against the detrimental effects of cancer cachexia