<正>Objective: To explore the effect of gamma irradiation on nuclear factor-kappa B in cultured bone marrow stromal cells. Methods: Immunocytochemistry

Western blot and electrophoretic mobility shift assay （EMSA） were used. Results: The expression of NF-kB in cultured mouse bone marrow stromal cells （BM-SCs） on the level of protein was elevated after exposure to 60Co in the dosage of 8. 0 Gy with the use of im-munocytochemistry and Western blot. The activity of nuclear factor-kappa B in cultured BMSCs was significantly increased after exposure to gamma irradiation by using EMSA. The activity peak was at the 4th h after irradiation. Conclusion: Our results suggest that the activation of nuclear factor-kappa B in the BMSCs after irradiation may be involved in the protection of BMSCs against apoptosis and in the recovery of hematopoiesis after radiation.