The regeneration of stem cells after a bone marrow depression induced by thiamphenicol

Thiamphenicol (TAP) administered subcutaneously for 4 days via a dialysis bag to bled mice, caused a total inhibition of the differentiation of BFUE into CFUE. The femoral BFUE numbers remained constant whereas the CFUE compartment was virtually absent. The proliferation of CFUs and BFUE was inhibited as well. The granuloid cell line was hardly affected. Shortly after removal of the drug, proliferation of CFUs and BFUE was resumed and a specific time sequence in the regeneration of erythropoiesis in marrow and spleen was observed. A decline in the number in BFUE in the femoral marrow was followed by an increase in the total CFUE in the marrow and an increase in the number of BFUE in the femoral marrow was followed by an increase in the total CFUE in the marrow and an increase in the number of BFUE in the spleen. Maximal erythropoiesis in the spleen occurred 1-2 days later than in marrow. The first wave of erythropoiesis in marrow was followed by a second one leading to high normal values of femoral stem cells. Spleen erythropoiesis consisted of one wave of proliferation and differentiation. The experimental system offers a valuable model for studying certain aspects of erythropoiesis and provides good starting material for CFUE isolation.