IN-VIVO EFFECT OF PLATELET FACTOR-4 (PF4) AND TETRAPEPTIDE ACSDKP ON HEMATOPOIESIS OF MICE TREATED WITH 5-FLUOROURACIL

In vivo effects of platelet factor 4 (PF4) and tetrapeptide N-acetyl-S er-Asp-Lys-Pro (AcSDKP) on haemopoietic progenitors were studied in mi ce treated with 5-fluorouracil (5-FU), The mice were injected with PF4 (40 mu g/kg) or AcSDKP (4 mu g/kg) twice at 6 h intervals, and 20 h a fter the second injection they were given one injection of 5-FU (150 m g/kg). 6, 8 and 13 d later the high proliferative potential-colony for ming cell (HPP-CFC), burst-forming unit erythroid (BFU-E), colony form ing unit granulocyte-macrophage (CFU-GM) colony forming unit megakaryo cyte (CFU-MK), and megakaryocytes (MK) were examined. The results show ed that the administration of PF4 or AcSDKP resulted in a significant increase in the number of HPP-CFC on days 6-8 and BFU-E and CFU-GM on day 8 when compared to 5-FU alone. Furthermore, PF4 was found to incre ase significantly the number of CFU-MK and MK on day 8, which was not observed with AcSDKP. However, both molecules had no obvious effect on peripheral blood cells, These data indicate that PF4 or AcSDKP accele rate the recovery in vivo of HPP-CFC, CFU-GM and BFU-E after 5-FU trea tment but their effect may be different on megakaryocytic progenitors and suggests that both molecules may have a haemoprotective effect aga inst chemotherapeutic agents.