OBJECTIVE: To establish an in vitro model of radiation-induced lung injury using rat lung alveolar macrophages (NR8383).METHODS: Using a medical electronic linear accelerator,cells were irradiated with either 0 Gy or 6 Gy X-rays.At 6,12,24,30 and 48 h,the DNA damage index (8-OHdG) and lipid damage index (MDA) were measured in the two groups.We also determined the levels of tumor necrosis factor-alpha (TNF-α),interleukin-6 (IL-6) and transforming growth factor-β (TGF-β).RESULTS: The levels of 8-OHdG and MDA in the 6 Gy irradiation group were higher than those in the 0 Gy group at 6,12,24,30 and 48 h after irradiation.The levels reached the highest value-6 h after irradiation,and then gradually decreased.The levels of the inflammatory factors TNF-α,TGF-β and IL-6 were higher in the 6 Gy irradiation group than those in the 0 Gy group at 6,12,24,30 and 48 h after irradiation.CONCLUSION: Six Gy X-ray irradiated NR8383 cells can be used to establish an in-vitro model of radiation-induced lung injury.The levels of 8-OHdG,MDA,TNF-α,TGF-β and IL-6 can be used as effective evaluation indicators.