EXERCISE EFFECTS ON LUNG-TUMOR METASTASES AND IN-VITRO ALVEOLAR MACROPHAGE ANTITUMOR CYTOTOXICITY

This study examined the effects of moderate and prolonged exercise on 1) lung tumor metastases and 2) alveolar macrophage antitumor response in vitro. C57B1/6 mice were assigned to either Ex-30 (30-min run), Ex -F (run to fatigue), Ex-F-24 h (run to fatigue 24 h before tumor injec tion), or Con (rested in lanes above the treadmill). Mice received int ravenous injections of syngeneic B16 melanoma cells 30 min postexercis e. Lungs were removed 7 or 10 days later, and tumor foci were counted. Ex-F had fewer tumors than either Ex-30 or Con, whereas Ex-F-24 h als o showed a strong trend toward fewer tumors. The initial localization of tumor cells in the lungs after injection was not different among gr oups. For the in vitro experiment, mice were killed immediately after exercise or 8 h later. Alveolar macrophages were removed and cultured in vitro with B16 melanoma cells. The growth of the tumors cultured wi th macrophages from Ex-F was lower than Con after exercise and, to a l esser extent, 8 h later. In Ex-30, this effect was only found immediat ely after exercise. The data suggest that prolonged exercise has a pro tective effect on lung tumor metastases and enhances alveolar macropha ge antitumor cytotoxicity.