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 microg/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.