Characterization of bone marrow mononuclear cells. (A) The identity of BMMC subpopulation was investigated by fluorescent-activated cell sorting (FACS) with antibodies recognizing Sca-1, Mac-1, GR-1, CD45, CD34, and CD133. (B) After Ficoll gradient (an isolation procedure as seen in clinical trials), the db/db group has significantly lower mononuclear (MN) cell fraction and Sca-1 population but higher Mac-11+/Gr-1+ fraction. This indicates that the db/db BMMC injections used have a significantly lower fraction of MN cells than the control BMMC injections. Moreover, within the db/db group there is a higher contamination of granulocytes. No significant differences in CD45negCD34+ or CD45negCD133+ were found (data not shown). Graphs represent 3 independent experiments. Abbreviations: BMMCs, bone marrow mononuclear cells.