Inhibitory effects of pretreatment with radon on acute alcohol-induced hepatopathy in mice

Abstract

We previously reported that radon inhalation activates antioxidative functions in the liver and inhibits carbon tetrachloride-induced hepatopathy in mice. In addition, it has been reported that reactive oxygen species contribute to alcohol-induced hepatopathy. In this study, we examined the inhibitory effects of radon inhalation on acute alcohol-induced hepatopathy in mice. C57BL/6J mice were subjected to intraperitoneal injection of 50% alcohol (5 g/kg bodyweight) after inhaling approximately 4000 Bq/m(3) radon for 24 h. Alcohol administration significantly increased the activities of glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) in serum, and the levels of triglyceride and lipid peroxide in the liver, suggesting acute alcohol-induced hepatopathy. Radon inhalation activated antioxidative functions in the liver. Furthermore, pretreatment with radon inhibited the depression of hepatic functions and antioxidative functions. These findings suggested that radon inhalation activated antioxidative functions in the liver and inhibited acute alcohol-induced hepatopathy in mice.

Figure 1

Schematic diagram of the radon exposure system (a). Changes in the radon concentration in the mouse cage over the period of sham (b) or radon inhalation (c).

Figure 2

Effects of radon inhalation on hepatic function-associated parameters in the serum of alcohol-administrated mice. Each value indicates the mean ± SEM. The number of mice per experimental point is 4–6. *P < 0.05, **P < 0.01, ***P < 0.001 versus each saline administrated mice. ^# P < 0.05, ^## P < 0.01 versus sham-inhaled and alcohol-administrated mice.

Figure 3

Effects of radon inhalation on TG level in liver (a) and histological changes in mouse liver after 24 hours following alcohol administration. (b), (c) sham inhalation before saline administration; (d), (e) sham inhalation before alcohol administration; (f), (g) radon inhalation before alcohol administration. The length of the scale bar is 20 μm. All samples were stained with HE. The area of the vacuole formations surrounding the central vein (cv) and portal vein (pv). Each value indicates the mean ± SEM. The number of mice per experimental point is 4–6. *P < 0.05, ***P < 0.001 versus each saline-administrated mice.

Figure 4

Effects of radon inhalation on lipid peroxide level in liver after alcohol administration. Each value indicates the mean ± SEM. The number of mice per experimental point is 5-6. *P < 0.05, **P < 0.01 versus each saline-administrated mice, ^# P < 0.05 versus sham inhaled and alcohol-administrated mice.

Figure 5

Effects of radon inhalation on antioxidative-associated parameters in mouse liver after alcohol administration. Each value indicates the mean ± SEM. The number of mice per experimental point was 5-6. *P < 0.05, **P < 0.01, and ***P < 0.001 versus each saline-administrated mice, ^# P < 0.05, versus sham inhaled and alcohol-administrated mice, and ⁺ P < 0.05, ⁺⁺ P < 0.01 versus sham-inhaled and saline-administrated mice.