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-OHd G) 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-OHd G and MDA in the 6 Gy irradiation group were higher than those in the0 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-OHd G,MDA, TNF-α, TGF-β and IL-6 can be used as effective evaluation indicators.