Fig. 1. Isolation and characterisation of SP cells from bone marrow. SP cells were isolated from hoechst 33342 stained ROSA26 bone marrow by flow cytometry sorting. (A) SP cells from bone marrow were identified and sorted as defined by gate R2. (B) Bone marrow-derived SP cells were found to be a defined population of cells that exhibited low side scatter. (C) Analysis of SP cells shows that 69.16% of the cells expressed Sca-1 whereas 4.20% expressed Gr-1. (D) Analysis of hematoxylin stained SP cells showed them to have low cytoplasm to nuclear ratios.