Morphology and proliferation differences among three types of MSCs. a–c BM-MSCs, AD-MSCs, and SM-MSCs were isolated from the bone marrow, adipose tissue, and synovium, respectively. Images show the MSCs at passage 3. Magnification ×10, bar 50 µm. d All three types of MSCs were seeded in a 96-well plate at 5 × 103 per well and were cultured for 1, 2, 3, 4, 5, and 6 days. The cell numbers at each day were measured using CCK-8 assay. The cells on day 0 were used as control. The data were obtained from three independent experiments, each performed in triplicate. Each bar represents mean ± SD (*p < 0.05, vs. BM-MSCs, at the same time point, ANOVA).