NEGLIGIBLE CONTRIBUTION OF SPLENIC ERYTHROPOIESIS TO RECOVERY FROM ANEMIA IN RATS

Abstract

The contribution of extramedullary erythropoiesis in the spleen during recovery from anemia was examined in rats. Six- and 18-week-old female Wistar rats were subjected to a total splenectomy or sham-splenectomy, and anemia was induced by bleeding the next day. Removing approximately 20% of the total volume of blood in the body resulted in a 9-26% reduction in erythrocyte count, hematocrit, and hemoglobin 3 days after bleeding, but the values returned to normal within 8 days of bleeding in young rats and within 14 days of bleeding in adult rats. Histology, image analysis, and differential cell counts revealed a marked increase in erythropoiesis in the spleen and femoral bone marrow in shamsplenectomy rats after bleeding; however, there were no statistical differences in hematology or bone marrow histology between the splenectomy and sham-splenectomy groups. These results indicate that the contribution of splenic erythropoiesis to the recovery from anemia was negligible in both young and adult rats.