Synergistic effect of chondroitin sulfate and cyclic pressure on biochemical and morphological properties of chondrocytes from articular cartilage

Objective: To investigate the synergistic effect of chondroitin sulfate (CS) and cyclic pressure on the biochemical and morphological properties of chondrocytes isolated from articular cartilage and cultured in alginate matrix. Methods: The chondrocytes obtained from articular cartilage of goat femoropatellar joint were isolated and cultured in alginate matrix. The cells were exposed to CS (100 mu g/ml) along with cyclic pressure of 1.2 MPa and 2.4 MPa and biochemical analysis of DNA, proteoglycan. collagen and protease activity was carried out in different matrix fractions, i.e., cellular matrix (CM) and further removed matrix (FRM) and in culture medium. The morphological studies of chondrocytes were carried out using transmission electron microscopy (TEM). Results: The treatment of chondrocytes with CS along with cyclic pressure increased the rate of cell proliferation relative to control (without load and in the absence of CS) and CS alone (P < 0.001). The proteoglycan content in CM increased in the presence of CS alone (P < 0.05) as well as CS with cyclic pressure (P < 0.001). The specific activity of protease in CM and FRM decreased in the presence of CS with cyclic pressure relative to control (P < 0.001). The TEM images showed abundant CM, improved cell morphology and matrix organization in the presence of CS and cyclic load treatment. Conclusions: The results of this study suggested that in the presence of CS along with cyclic loading, the cellular ability to utilize and incorporate exogenous CS as extracellular matrix improved, as compared to CS alone. (C) 2008 Osteoartritis Research Society International. Published by Elsevier Ltd. All rights reserved.