BASIC FIBROBLAST GROWTH-FACTOR RADIOPROTECTS BONE-MARROW AND NOT RIF1TUMOR

We examined the potential of bFGF to function as a radioprotector of b one marrow (BM). Total intravenous doses of bFGF ranged from 1 to 24 m u g/mouse, in 2 divided doses. Whole body radiation (WBI) was given in a single fraction to C3H mice. Histologic observations were performed on femur BM at various times after bFGF (or placebo) treatment. Thigh radiation in thigh-tumor bearing mice was delivered in a single fract ion, bFGF increased the LD(50/30) of mice in a dose dependent fashion, with an apparent maximum protection obtained with greater than or equ al to 6 mu g given half 24 h and half 4 h before irradiation. BM histo logy shows prominent recovery of megakaryocytes and all cell lineages along with less loss in cellularity compared to control irradiated ani mals. No radioprotection of RIF1 tumors after bFGF was detected. These results indicate that bFGF may be a selective radioprotector of norma l tissue.