IMPROVEMENT OF ERYTHROID TOXICITY BY LENTINAN AND ERYTHROPOIETIN IN MICE TREATED WITH CHEMOTHERAPEUTIC-AGENTS

Lentinan, an antitumor polysaccharide, has been assessed for its poten tial in vivo to augment erythroid progenitor cells and protect them fr om the cytotoxic effects of antitumor chemotherapeutics. Lentinan augm ented the level of burst-forming units-erythroid (BFU-E) and accelerat ed the recovery of the reduced number of BFU-E in mice treated with 5- fluorouracil (5-FU); lentinan did not influence red blood cell counts or colony-forming unit-erythroid (CFU-E) numbers in the femoral marrow . A significant decrease in stem cell inhibitory factor (SCIF) activit ies in bone marrow and an increase in colony-forming unit-spleen (CFU- S) formation were observed in the lentinan-treated mice. The mechanism of augmented BFU-E formation may be partly due to augmented productio n of stem cells, giving rise to both CFU-GM and BFU-E. Furthermore, wh en lentinan administration was followed by administration of erythropo ietin (Epo) in 5-FU-treated mice, increases in femoral marrow and sple nic CFU-E formation and augmentation of reticulocyte counts were obser ved beyond the level observed in mice treated with Epo alone. These re sults suggest that lentinan may augment the effects of Epo on erythrop oiesis in the course of anemia and the decreased erythropoiesis in can cer patients receiving chemotherapy.