To induce chondrogenic differentiation, 200,000 MSCs were placed in a 15-mL polypropylene tube and centrifuged at 1,000 rpm for 5 min. Pellets were then cultured at 37°C in 5% CO2 and 300 μL of serum-free chondrogenic medium consisting of Dulbecco's modified Eagle medium-high glucose (DMEM-HG, JBI) supplemented with 10 ng/mL of transforming growth factor-β3 (TGF-β3, R&D Systems, Minneapolis, MN, USA), 100 nM dexamethasone (Sigma-Aldrich, St. Louis, MO, USA), 50 μg/mL ascorbate-2-phosphate, 100 μg/mL pyruvate, and 50 mg/mL ITS + Premix (Becton Dickinson Biosciences, Bedford, MA, USA; 6.25 μg/mL insulin, 6.25 μg/mL transferrin, 6.25 ng/mL selenious acid, 1.25 mg/mL bovine serum albumin [BSA], and 5.35 mg/ mL linolenic acid); the medium was replaced every 2-3 days for 3, 7, 14, or 21 days.