Fig 2.

FACS-purification yields a myoblast population expressing a defined rVEGF level. Control rICD8 cells (A), primary transduced rVICD8 myoblasts (B) and clones expressing moderate (C, clone 2) or high VEGF levels (D, clone 8) were implanted in the posterior auricularis muscle of SCID mice. Four weeks later, vascular morphology was analszed in tissue whole-mounts by lectin staining (brown) and myoblast engraftment was revealed by X-Gal staining (blue). Size bars 50 m. (E) Clone 2, producing 53.5 ± 2.1 ng of rVEGF/10⁶ cells/day, was chosen as the reference clone. Its range of fluorescence intensity (pink shade) was divided into eight equal parts, shown by the vertical lines on the logarithmic scale of the FACS plot, and the middle two octiles (25%) defined the sorting gate (red shade). (F) This gate (black segment bar) was applied to the heterogeneous rVICD8 population (red curve) to yield the purified population (blue curve). The reference clone (black curve) and the negative control cells (grey-tinted curve) are also shown.