Acidic fibroblast growth factor (FGF1) increases survival and haematopoietic recovery in total body irradiated C3H/HeNCr mice.

Basic fibroblast growth factor is known to stimulate the proliferation of bone marrow stem and/or progenitor cells in vitro and in vivo. We examined a similar cytokine, acidic fibroblast growth factor (FGF1), for its in vivo radiomodifying effects. Female C3H/HeNCr mice were given human recombinant FGF1 intravenously at doses ranging from 1 to 24 micrograms. FGF1 was delivered in two equal doses 24 and 4 h before or 24 h after otherwise lethal total body irradiation (TBI). In vivo FGF1 radioprotection of C3H mice was maximized at a total dose of 12 micrograms/mouse given before TBI. The radiomodification was 1.16 +/- 0.03 (+/- 1 SD) with an increase of LD50/30 from 736 +/- 9 to 854 +/- 16 cGy (P < 0.01). Some retroactive radiomodification was observed even when FGF1 was given 24 h after irradiation (P < 0.05). FGF1 radioprotected mice by improving the repopulation of haematopoietic progenitor cells of bone marrow. The radioprotection was not associated with an increase in S-phase fraction or detectable circulating IL-3, TNF-alpha or GM-CSF, suggesting that other mechanisms of protection were responsible.