Inhibitory effects of radon inhalation on CCl4-induced mouse liver damage and its best inhalation condition

Abstract

We previously reported that radon inhalation or low-dose X-irradiation activated antioxidative functions and inhibited alcohol-induced or carbon tetrachloride (CCl₄)-induced oxidative damage in mouse liver. However, there are no reports on the best radon inhalation condition of these inhibitory effects. In the present study, we examined the inhibitory effects of radon inhalation on CCl₄-induced hepatopathy in mice and its best inhalation condition. BALB/c mice (age: eight weeks; body weight: approximately 25 g) were intraperitoneally injected CCl₄. Before or after CCl₄ injection, mice were inhaled approximately 20,000 Bq/m³ radon for 6 hours. We investigated the various biochemical parameters, such as the activities of transaminase and antioxidation in these hepatopathic mice. In result, the activities of glutamic oxaloacetic transaminase and glutamic pyruvic transaminase in serum were significantly increased by CCl₄ injection, suggesting that CCl₄ injection induced hepatopathy. Histological examination also showed hepatopathy of these mice. Radon inhalation increased total glutathione content in liver, suggesting that radon inhalation activates antioxidative function. We will report the best radon inhalation condition of the inhibitory effects of hepatopathy in comparison with the other radon inhalation conditions.