ABSTRACT
PURPOSE: Articular cartilage is under continuous mechanical stresses during daily activity. The mechanical force must also be applied during the culturing process to produce a phenotypically correct tissue. We have developed bioreactor, capable to apply the three main fluid-induced stresses: shear stress, compression, and hydrostatic pressure. The objective of this study was to investigate the effects of bioreactor on chondrocyte proliferation and matrix synthesis in articular chondrocytes and to determine the most appropiate chondrogenesis biomechanical environment. MATERIALS AND METHODS: Articular cartilage was harvested from the rabbit knee. Isolated chondrocytes from articular cartilage were cultured in static culture and bioreactor culture. Bioreactor culture condition was fluid rate of 0.2 cm/sec and shear stress of 0.6x10-3 dyn/cm2 After 3 days, the effects of fluid-induced shear stress were evaluated by measuring the cell proliferation, observation of cell morphology and expression of cartilage specitic ECM using Histology, and Immunocytochemistrical staining. RESULTS: We have developed bioreactor and subjected chondrocytes to fluid-induced shear stress of 0.6x10-3 dyn/cm2 for 3 days. We observed changes in chondrocyte shape, orientation, and nodule formation. In metabolic studies, the application of fluid-induced shear stress to articular chondrocytes resulted in a significant increase in the proliferation of chondrocytes and the synthesis of type II collagen compared to that of in the static culture. CONCLUSION: From these results, it was concluded that the bioreactor which we developed produced appropriate chondrogenesis biomechanical environment.