During hematopoiesis of mammalian animals, an erythroblastic island in the bone marrow has been reported to contain a central macrophage surrounded by many erythroblasts. Fetal mouse livers and spleens, which are treated with collagenase, have been used to get the erythroblastic island in tissue cultures. In this study, we have cultured some stamped cells obtained from spleens of anemic mice and examined their structures by scanning electron microscopy.

Hemolytic anemia of female BALB/c mice was induced by acetylphenylhydrazine (4mg/g body weight) injection for 5 days. Spleens were resected on the second day after the last injection and a “spleen-stamp culture“ method was performed. Briefly, they were cut with razor blades (Fig. 1a) and splenic cells on the cut tissue surface were stamped on collagen-coated coverslips (Fig.1b). The stamped splenic cells were covered with dialysis membranes (Fig. 1c). They were cultured with 55% IMDM, 20% L-15 and 25% FBS, containing 2U/ml erythropoietin (EPO) in humidified atmosphere of 5% CO2 at 37°C for 1-3 days.