Preliminary study of protective effects of flavonoids against radiation-induced lung injury in mice.

BACKGROUND Radiation therapy plays an important role in lung carcinoma treatment. However, the incidence of symptomatic radiation-induced lung injury is high. This study aimed to evaluate radioprotective effects of flavonoids extracted from Astragalus complanatus and mechanisms of action against radiation damage. METHODS Alteration in antioxidant status and levles of several cytokines were investigated in BABL/C mice treated with 4 mg/kg b.wt. flavonoids after exposure to 10Gy thoracic radiation. RESULTS Serum levels of SOD in the flavonoids+radiation group were significantly higher compared to the radiation control group, while TGF-β1 and IL-6 were lower. Mice in the radiation control group displayed more severe lung damage compared with the flavonoids+radiation group. The expression of TGF-β1 and TNF-α in the radiation control group was markedly increased in alveolar epithelial cells and macrophages of the alveolar septum. CONCLUSIONS From the results of the present study, flavonoids could be excellent candidates as protective agents against radiation-induced lung injury.