Figure 5. Colony formation of human ADSCs was assayed. The clonogenic ability of primary ADSCs on the sixth day was analyzed by seeding cells in 35 mm dishes at an indicated cell density for two weeks of culture. Formed colonies were stained with crystal violet solution. Colony forming unit (CFU) containing at least ten cells was defined as a colony and counted under a microscope. (A) 100 cells/dish; (B) 300 cells/dish; (C) 400 cells/dish; (D) The quantities of CFU showed that colony formation of ADSCs increased in a cell concentration-dependent manner. Values were presented as means ± SD (n = 3). *P < 0.05 group B or C vs. group A.