Isolation and Characterization of Mesenchymal Stem Cells

The Institutional Review Board (IRB) and Ethical Committee of Zhejiang University, Hangzhou, China, approved this study. Whole-bone marrow samples were collected from healthy donors at the First Affiliated Hospital, Zhejiang University. All donors provided the written informed consent. Bone marrow cells were isolated and purified from bone marrow according to the methods of Zhang et al. [3 (link)]. The harvested cells were seeded in a 10 cm dish with α-MEM culture medium (Gibco, Shanghai, China) supplemented with 10% FBS, 100 U/mL penicillin, 100 μg/mL streptomycin (Gibco), and 5 ng/mL basic fibroblast growth factor (BFGF; Life Technologies, Shanghai, China) and cultured at 37°C, 5% CO₂, and 95% humidity. Cells at approximately 80% confluency were trypsinized and reseeded at a density of 1 × 10⁵ cells/mL as passage 1. Cells at passage 3 were used for this study. These cells were characterized by surface markers CD19−, CD34−, CD14−, CD45−, HLA-DR−, CD105+, CD90+, CD73+, and CD29+ and showed the potentials of osteogenesis and adipogenesis.