Membrane surface properties of rat bone marrow cells as determined by partition in two-polymer aqueous phase systems: Cells containing hemoglobin

Partition of cells in two-polymer aqueous phase systems is a sensitive indicator of cell surface properties (primarily surface charge [13]). In general, a higher partition coefficient reflects a higher surface charge. Hemoglobin-containing bone marrow cells from normal and from phenylhydrazine-injected rats were studied by this method. Changes in partition of reticulocytes [7] and erythrocytes [16] with increasing age have previously been described. 1. 1. The countercurrent distribution of hemoglobin-containing bone marrow cell populations from normal and erythroid cell stressed (i.e., phenylhydrazine-injected) rats consists of two peaks. Normal rats have a small left (lower partition) peak and a larger one to the right (higher partition); in stressed rats the relative peak sizes are reversed. Furthermore, the normal marrow distribution curve is virtually identical to that obtained with peripheral red blood cells from stressed rats. 2. 2. Microscopic examination of hemoglobin-containing bone marrow cells after countercurrent distribution reveals that the cells that are nucleated and contain less hemoglobin are to the left; cells that are non-nucleated and contain more hemoglobin are to the right. 59Fe-ferrous citrate is incorporated (both in vivo and in vitro) to a greater extent by the cells to the left in both normal and stressed rats. 3. 3. The countercurrent distribution pattern of bone marrow cells other than those containing hemoglobin appears unchanged in both normal and phenylhydrazine-injected rats indicating that the most obvious effect of phenylhydrazine is on erythroid cells. The distribution pattern of hemoglobin-containing bone marrow cells in stressed rats returns to normal within a week after phenylhydrazine injection stops reflecting recovery of the rats (but not recovery of normal surface properties by abnormal cells [8]). 4. 4. Based on the above data and on those previously obtained with reticulocytes [7, 8] and erythrocytes [16] a discussion is presented on the surface properties, as determined by partition of nucleated, hemoglobin-containing bone marrow cells and the changes they undergo from their appearance to erythrocyte disappearance from the peripheral blood (i.e., during the maturation and aging process).