Effects of Basic Fibroblast Growth Factor on Radiation-Induced Proliferation Inhibition and Apoptosis in Thymocytes and Splenocytes

Fibroblast growth factors (FGFs) stimulate the proliferation of a variety of cells and protect against stress-induced apoptosis. We have demonstrated that basic FGF (bFGF) significantly stimulates intestinal cell proliferation and protects against dexamethasone-induced apoptosis. In this study, we further investigate the effects of bFGF on radiation-induced inhibition of thymocyte and splenocyte proliferation and apoptotic cell death. Mice were subjected to whole-body X-rays irradiation by at a dose of 0.5 Gy or 1.0 Gy and 14 hr later thymocytes and splenocytes were collected for in vitro culture with or without bFGF. Radiation induced a significant decrease in the cell proliferation of both thymocytes and splenocytes, which was not significantly inhibited by incubation with bFGF. Radiation with 0.5 and 1.0 Gy also significantly increased apoptotic cell death in both thymocytes and splenocytes, and incubation with bFGF did not significantly affect the apoptotic effects of radiation. These results suggest that incubation of bFGF in vitro with thymocytes and splenocytes from irradiated mice did not significantly prevent radiation-induced inhibition of cell proliferation and apoptotic effects.