Tendon cell contraction of collagen-GAG matrices in vitro: effect of cross-linking

The contraction of connective tissue cells can play important roles in woun d healing and pathological contractures. The effects of this contractile be havior on cell-seeded constructs for tissue engineering have not yet been i nvestigated. The goal of this work was to investigate in vitro tendon cell- mediated contraction of collagen-glycosaminoglycan (GAG) matrices cross-lin ked using selected methods. Highly porous collagen-GAG sponges were seeded with calf tendon cells and the projected area and DNA content of the sponge s measured at 3, 7, 14, and 21 days post-seeding. Immunohistochemistry was performed to determine if cc-smooth muscle actin (SMA) was associated with the cell contraction of the matrices. Dehydrothermal (DHT) treatment alone was not sufficient to resist contraction by the seeded tendon fibroblasts. Cross-linking of the collagen-GAG sponges to the extent that the modulus wa s three times that of sponges treated by DHT alone was necessary to resist contraction. SMA was seen in the cytoplasm of most cells in all sponges at all time periods. The results provide a rational basis for the determinatio n of the mechanical properties of collagen matrices required for engineerin g certain connective tissues. (C) 2000 Elsevier Science Ltd. All rights res erved.