Isolation and Expansion of Osteoarthritic Chondrocytes

Cartilage tissue was obtained from three patients suffering from end stage OA and undergoing total knee arthroplasty (ages 47, 60 and 82 years; all female) at the university hospital of Basel under ethical agreement (Ethikkommission beider Basel, Ref.Nr. EK: 78/07, 20. March 2007). The cells were isolated as described elsewhere [69 (link)]. Briefly, tissue samples were minced with a scalpel into small pieces and were digested overnight in 0.2% collagenase II (300 U/mg, Worthington Biochemical Corp, Lakewood, NJ, USA) on an orbital shaker at 37 °C. Then, the isolated chondrocytes were expanded for three passages to 80% confluency in basal medium (BM, Dulbecco’s modified Eagle medium, high glucose (DMEM)), 10 mM HEPES, 1 mM sodium pyruvate, 1% penicillin/streptomycin (P/S), 100 μg/mL streptomycin, and 0.29 mg/mL glutamate (all from Gibco, Paisley, UK), supplemented with 10% fetal bovine serum (FBS), 5 ng/mL fibroblast growth factor-2 (FGF-2) and 1 ng/mL transforming growth factor (TGF)ß1 (both from Fitzgerald, Acton, MO, USA) in a humidified incubator (37 °C, 5% CO₂).