THE EFFECT OF TREADMILL EXERCISE ON THE DEVELOPMENT OF PROSTATE CANCER IN RATS 1195

Abstract

It is now evident that both acute and chronic exercise have an effect on the immune system. Moderate exercise training has been shown to significantly increase serum immunoglobulins, monocytes, as well as NK cell number and activity. The influence of physical activity on prostate cancer is a topic which has not been well investigated. Therefore, the purpose of this study was to examine the effect of moderate treadmill exercise on the development of prostate cancer in rats. Forty male Lobund-Wistar rats were randomly assigned to aerobic exercise (AE: n=20) or control (C: n=20) groups. Aerobic exercise consisted of running on a motor-driven treadmill at 20 m/min (73.2 ± 12.6% VO2 max), 15 min/day, three times weekly for six weeks. Following exercise, all animals were inoculated with 1 × 106 transplantable rat prostate cancer (PA-III) subcutaneously on the back, above the sacral region (day = 0). The AE group exercised an additional 2 weeks post inoculation. Max VO2 did not change in either group during the initial six-week training period (AE: 65.52 ± 6.16 vs 65.72 ± 4.29; C: 65.79 ± 4.34 vs. 64.36 ± 4.86, ml/kg/min). At day 30, the number of rats displaying tumor (AE: 20 vs C: 18) and the total tumor volume (AE: 7305.2 ± 3313.4 vs C: 9134.9 ± 6509.6, mm3) did not differ between groups. Lung tissue collected from 10 AE and 10 C at day 30 showed no differences in metastatic lesions. In conclusion, the treadmill exercise protocol was not sufficient to elicit a training response and had no effect on the incidence or growth of prostate cancer in rats at day 30. Future studies need to consider a greater dose of exercise in order to determine its efficacy.