抄録
The pathogenesis of aplastic anemia has not been clarified, but stem cell failure has been considered as the basis of development of the disease.
Chloramphenicol (CP) has been suggested to be one of causative agents for aplastic anemia.
We have studied the in vivo effect of CP on hemopoietic stem cells in normal mice. Numbers of in vitro colony-forming cells (CFU-C) and spleen colony-forming cells (CFU-S) were not significantly changed in femur or spleen of the mice injected with large dose of CP for long period, notwithstanding an inhibitory effect of CP on colony growth in vitro. Then, we investigated the effect of CP on CFU-C in W-anemic mice in which number of CFU-S is extremely reduced, and produced the various hemopoietic states to observe the effect of CP administration on the stem cell.
In in vivo experiments using W-anemic mice, CFU-C of the femur and spleen was not influenced by CP administrations.
A remarkable increase of CFU-C in the spleen was observed after endotoxin injections, in which CP worked as an inhibiting agent. Both CFU-C and CFU-S were reduced by CP administration in mice which received syngeneic bone marrow transplantation after lethal irradiation. A mode of action of CP on hemopoietic stem cells in vivo was discussed on the bases of these results.
