Effect of Voluntary Exercise on Azoxymethane-induced Colon Carcinogenesis in Male F344 Rats

The effect of voluntary exercise on azoxymethane (AOM; CAS: 25843-45-2)-induced colon carcinogenesis was investigated in male F344 rats. Beginning at 5 wk of age, all animals were divided into two groups (sedentary and exercise) and fed AIN-76A semipurified diet ad libitum. At 7 wk of age, animals were given AOM s.c. at a dose level of 15 mg/kg of body weight, once weekly for 2 wk. Four days after the second dose of AOM, all animals in the exercise group were housed in individual wheel-cage units, and the animals in the sedentary group were housed in plastic cages. The experiment was terminated at 38 wk post-AOM treatment. Body weights of animals in the exercise and sedentary groups were comparable. The incidence (percentage of animals with tumors) and multiplicity (tumors/animal) of colon adenocarcinomas were significantly inhibited in the exercise group, but the incidence and multiplicity of colon adenomas were unaffected by the exercise. The incidence of small intestinal adenocarcinomas and liver foci was also inhibited in the exercise group.