The possible applications of radon inhalation treatment as antioxidant therapy for hepatopathy

The possibility of antioxidant therapy has been reported for several diseases such as ischemic stroke. The therapy could also be applied for diseases caused by reactive oxygen species (ROS). It has been reported that ROS or free radicals may cause various types of hepatopathy, including alcoholic liver disease. Low dose (0.5 Gy) X- or γ- irradiation activates the antioxidative functions of the mouse liver and inhibits ROS- or free radical-induced hepatopathy. Radon therapy is performed mainly for pain-related diseases in Japan and Europe. Several clinical studies have been reported, but the possible mechanisms of the beneficial effects remain unknown. Recently, we have reported that the possible mechanism of radon therapy is the activation of antioxidative functions following radon inhalation. For example, radon inhalation inhibits and alleviates chronic constriction injury induced pain or inflammatory pain in mice due to the activation of antioxidative functions. In addition, although hepatopathy is not the main indication for radon therapy, our recent studies suggested that radon inhalation inhibits hepatopathy caused by ROS or free radicals. In this chapter, based on experiments with mice, we reviewed the possible applications of radon inhalation as an antioxidant therapy for hepatopathy from the viewpoints of recent antioxidant therapy, hepatopathy induced by ROS or free radicals, and the beneficial effects of radon inhalation for hepatopathy.