FGF-2 signaling mediates expansion of HSPCs. C57BL/6 mice were treated with either PBS or FGF-2 (n > 7). (A,D) BM cellularity per femur and tibia or spleen cellularity. (B,E) Frequency of CFU-Cs in the BM or spleen. The total number of colonies per 1.5 × 104 BM or 2 × 105 spleen seeded cells is presented. (C,F) Representative flow cytometric dot plot analysis of BM or spleen SKL cells, numbers indicate mean percentage ± SEM of BM or spleen SKL cells. (G) Percentage of CD34− SKL cells determined by flow cytometry. (H) Representative flow cytometric analysis of CD34 expression on SKL cells. Numbers indicate mean percentage ± SEM. (I) B6.SJL recipient mice were lethally irradiated (n > 15 per time point per treatment) and transplanted with 2 × 105 BM cells from either PB- or FGF-2–treated donors (n > 5) together with recipient 4 × 105 BM cells. Mice were killed at the indicated time points and the levels of engraftment were determined. (J) CRU frequency and numbers were determined after sacrificing B6.SJL recipient mice transplanted with PBS- or FGF-2–treated donor-derived BM cells in limiting dilution (2.5 × 104 to 2 × 105) and measuring donor-derived myelolymphoid contribution among PB cells. *P < .05; **P < .01. Data shown are means ± SEM.
