Evaluation of mouse whole body bone marrow cellularity and distribution of hematopoietic progenitors

In order to perform murine transplant experiments, marrow cells are usually harvested from hind legs bones either by bone marrow flushing or bone crushing. We examined the feasibility of harvesting whole skeleton marrow in regards to cell numbers and progenitor potential. Bones of BALB/c mice were dissected and flushed with cold HBSS or crushed in a mortar with cold HBSS buffer. The obtained solution was filtered on a 40 μm strainer, then washed once. Cells were counted with a hemocytometer. For HPP analysis, 20,000 cells were plated in soft agar with 7 factors. Total marrow cell counts averaged 525 ± 34 × 106 cells/mouse (n = 7). Comparison of flushed hind legs (2 tibias, femurs, iliac) with crushed hind legs gave 114 and 96 × 106 cells, respectively. Crushed spine gave 170 × 106 cells. The progenitor content of each region, compared by HPP, is shown in the table (colonies/20,000 plated). Significant increase of progenitors was found between flushed and crushed legs and between legs and spine. Despite showing more total colonies, whole body showed equal percentages of HPP compared to crushed legs. The difference observed between flushed and crushed legs may indicate a cortical localization of progenitors. Total marrow harvest is feasible, economical and provides high numbers of hematopoietic cells rich in progenitors.