Effects of medium perfusion on matrix production by bovine chondrocytes inthree-dimensional collagen sponges

Various culture systems have been used for examining the anabolic and catab olic functions of isolated chondrocytes as well as for tissue engineering p urposes. Perfusion or frequent medium change is beneficial for three-dimens ional (3D) cultures of many cell types. In this study, bovine articular cho ndrocytes (bACs) were grown in 3D collagen sponges with or without medium p erfusion (0.33 mL/min) for up to 15 days. The influence of medium perfusion was evaluated using markers of cartilage matrix accumulation, synthesis, a nd gene expression. Metachromatic matrix, collagen type II, and hyaluronan accumulated around the cells within the collagen sponges. Sulfated glycosam inoglycans (S-GAGs) that accumulated in the sponge exposed to nonperfused c ontrol were 130% of that in the perfused sponge at day 7. S-GAG accumulatio n after 15 days in the nonperfused control was 230% more than at day 7 (p < 0.01). S-35-sulfate incorporation during the final 18 h of culture in the sponge exposed to nonperfusion was 180% greater than that in the perfused s ponge (p < 0.01). Quantitative analyses show that at day 7, aggrecan and co llagen type II gene expression were 350% and 240% greater, respectively, in the nonperfused culture than in the perfused one. These results indicate t hat perfused conditions that are beneficial for other cell types inhibit ch ondrogenesis by articular chondrocytes in 3D culture. (C) 2001 John Wiley & Sons, Inc.