Fig. 1.

Initial cell isolation and colony forming unit (CFU) potential. Synovium, marrow, and adipose tissues were obtained from five canine donors presenting for rupture of the cranial cruciate ligament. Cells were isolated using Ficoll™ centrifugation (marrow) or enzymatic digestion (synovium, adipose) and plated at clonal density. a Initial nucleated cell yield for all 15 donors, normalized to tissue weight. b Representative 10× objective phase-contrast microscopy images 7 days post isolation (bar = 100 μm). c CFU potential of primary cell populations for all 15 donors: 1 × 10³ total cells (synovium and adipose) or 4.5 × 10⁵ total cells (marrow) were seeded on 55-cm² plates and incubated for 21 days. Plates were stained with 0.3% crystal violet and colony counts were performed on each plate. CFU potential is defined as the number of colonies present divided by total number of seeded cells, expressed as a percentage of the total seeded cells. Data reported as mean ± SD (n = 3 plates/tissue). a, b, c denote significant differences between tissue sources of cMSCs (p < 0.0001). d Photographs of CFU plates from a single representative donor. For a and c, data are reported in descending order for each tissue type