Isolation of SP cells from murine bone marrow and skeletal muscle.

<p>A – Representative FACS plots of bone marrow cells stained with Hoechst 33342 and PI. All plots show 20,000 events. Addition of verapamil eliminated the SP. The linear X and Y axes show PI and Hoechst staining, respectively. B – Representative FACS plots of skeletal muscle cells stained with Hoechst 33342 and PI (20,000 events per plot) in the absence (left) or presence (right) of verapamil. C – The appearance of bone marrow (left) and skeletal muscle (right) SP cells under combined bright field and fluorescence illumination. EGFP-expressing SP cells are shown on a hemocytometer grid and scale bars represent 50 µm (left) and 10 µm (right). D – Representative intrinsic fluorescence in C2C12 cells and unfractionated bone marrow from EGFP-expressing mice. The X axis depicts forward scatter (FSC-H) using a linear scale and the Y axis shows fluorescence using a logarithmic scale. E – Representative fluorescence in MP and SP fractions in enzymatically-digested skeletal muscle from ACTB-EGFP transgenic mice.