Ultraviolet B (UVB)-pretreated SKH-1 mice were treated with water,
caffeine (0.1 mg/ml), voluntary running wheel exercise (RW) or
caffeine together with RW for 14 wk. Treatment of the mice with
caffeine, RW, or
caffeine plus RW decreased skin
tumors per mouse by 27%, 35%, and 62%, respectively, and the
tumor volume per mouse was decreased by 61%, 70%, and 85%, respectively. In mechanistic studies, mice were treated with water,
caffeine, RW, or
caffeine plus RW for 2 wk prior to a single irradiation with UVB.
Caffeine plus RW increased RW activity by 22% when compared with RW alone.
Caffeine ingestion was not significantly different between groups. Treatment of mice with
caffeine plus RW for 2 wk decreased the weight of the parametrial fat pads and stimulated the formation of UVB-induced apoptosis to a greater extent than treatment with
caffeine or RW alone. An antibody array revealed that
caffeine plus RW administered to mice fed a high-fat diet and irradiated with UVB decreased the epidermal levels of
lipopolysaccharide-induced
CXC chemokine, soluble
TNF alpha receptor-1, and macrophage inflammatory protein-1γ. Overall,
caffeine during RW exerts a stronger effect than either treatment alone for decreasing tissue fat, increasing UVB-induced apoptosis, lowering the levels of
cytokines associated with
inflammation and for inhibiting UVB-induced
carcinogenesis.