Both moderate exercise and the soluble fiber
beta-glucan can have beneficial effects on the initiation and growth of
tumors, but the data are limited, and there is no information on their combined effects. This study tested the independent and combined effects of short-term moderate-exercise training and the soluble oat fiber
beta-glucan (ObetaG) on the metatastic spread of injected
tumor cells and macrophage antitumor cytotoxicity. Male C57BL/6 mice were assigned to one of four groups: exercise (Ex)-H2O, Ex-ObetaG, control (Con)-H2O, or Con-ObetaG. ObetaG was fed in the
drinking water for 10 days before
tumor administration and death. Exercise consisted of treadmill running (1 h/day) for 6 days. After rest or exercise on the last day of training, syngeneic
B16 melanoma cells (2 x 10(5)) were administered via
intravenous injection (n = 8-11 per group). Lungs were removed 14 days later, and
tumor foci were counted. Additional mice (n = 8 per group) were killed, and peritoneal macrophages were assayed for cytotoxicity against the same mouse tumor cell line at various effector-to-target ratios. Both moderate exercise and ObetaG decreased lung
tumor foci and increased macrophage cytotoxicity. However, there were no differences in lung
tumor foci and macrophage cytotoxicity between Ex-ObetaG and either Ex-H2O or Con-ObetaG. These data suggest that, although not additive in their effects, both short-term moderate-exercise training and consumption of the soluble ObetaG can decrease the metatastic spread of injected
B16 melanoma cells, and these effects may be mediated in part by an increase in macrophage cytotoxicity to
B16 melanoma.