Chondrogenesis on BMP‐6 loaded chitosan scaffolds in stationary and dynamic cultures

We originally investigated the suitability of chitosan scaffolds loaded with bone morphogenetic protein 6 (BMP‐6) in both stationary and dynamic conditions for cartilage tissue engineering. In the first part of the present study, ATDC5 murine chondrogenic cells were seeded in chitosan and BMP‐6 loaded chitosan scaffolds and cultured for 28 days under static conditions. In the following part, we examined the influence of dynamic cultivation conditions over BMP‐6 loaded chitosan scaffolds by using rotating bioreactor with perfusion (RCMW?). Tissue engineered constructs were characterized by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐tetrazoliumbromide (MTT) assay, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and biochemical assays for glycosaminoglycans (GAG) deoxyribonucleic acid (DNA) and collagen Type II quantification. At the end of 4 weeks static incubation period high levels of GAG (21.22 mg/g dry weight), DNA amounts (1.37 mg/g dry weight) and collagen Type II amounts (1.94 µg/g dry weight) were achieved for BMP‐6 loaded chitosan scaffolds compared to chitosan scaffolds. However, the results obtained from morphological observations suggested hypertrophic differentiation of ATDC5 cells in the presence of BMP‐6 under stationary conditions. The influence of mechanical stimulation appeared significantly with differentiated cells, cultured under dynamic conditions, showing the effect of retaining their phenotypes without hypertrophy. Biotechnol. Bioeng. 2009; 104: 601–610 © 2009 Wiley Periodicals, Inc.