Research on change of FL expression in mice irradiated with gamma rays

Objective: FL is a growth factor acting on hematopoietic progenitors. To further study the relationship between FL level and hematopoietic injury caused by radiation, the expression of FL in mice after whole body irradiation was observed. Methods: C57BL/6J mice were irradiated with 2 Gy to 10 Gy of 60Co gamma rays. The expression level of FL in blood, bone, marrow, thymus and spleen of mice was quantified by methods of ELISA, FACS and Western blot. Results: (1) Following irradiation with 2 Gy to 10 Gy, mice showed a gradual increase of serum FL level beginning from the first day after irradiation. At the doses from 2 Gy to 6 Gy, the increase of serum FL level in mice after irradiation was correlated to radiation dose; (2)At the first day after 6 Gy irradiation, membrane-bound FL on white blood cells in the peripheral blood of mice increased slightly, but on the following days it was not higher in the irradiated mice than that in the normal controls; (3) The membrane-bound FL level in bone marrow, thrums and spleen of mice increased on the first day after 6 Gy irradiation ,so did the FL level in protein extraced from these three tissues as measured by Western blot. Conclusion: The expression level of soluble and membrane-bound FL in mice was significantly increased at the early stage following irradiation, and the level of serum FL was correlated with radiation dose and the time after irradiation. (authors)