Organ-specific modulation of antioxidant functions by combined voluntary exercise and radon inhalation in mice

Radon inhalation as well as voluntary exercise increase anti­oxidant function in experimental animals. However, the combined effects of radon inhalation and exercise on antioxidant functions have not yet been investigated. In this study, we examined the effects of combined voluntary wheel running (VWR) and radon inhalation on antioxidant functions in various organs of mice. Mice were individually housed in cages equipped with running wheels, and allowed voluntary exercise for 5, 15, or 25 days, followed by radon inhalation at 2,000 Bq/m3 for 24 ‍‍h. Antioxidant function was enhanced by the combined treatment in the kidneys, pancreas, spleen, and stomach, with responses varying according to exercise duration. In contrast, antioxidant function was reduced in the lungs and heart. No clear interaction effects of the combined treatment were observed in the liver, small intestine, colon, and brain. These findings suggest that the combined effects of voluntary exercise and radon inhalation on antioxidant functions are organ-specific and can be categorized into distinct response patterns across tissues.