The effect of hyaluronic acid with different molecular weights on collagen crosslink synthesis in cultured chondrocytes embedded in collagen gels

Hyaluronic acid (HA) is a component of the extracellular matrix of cartilage and has various effects on three-dimensional cultured chondrocytes. We measured Pyridinoline (Pyr), which is a crosslink of collagen in cultured chondrocyte-collagen composites treated with HA of different molecular weights to investigate the effects of the various molecular weights on collagen crosslink synthesis. The control group was collagen gel without cells; group N was treated without HA; and the others were treated with HA with an average molecular weight of 2.3 X 10(6) Da (group H), 8.0 X 10(5) Da (group M), and 2.3 X 10(4) Da (group L). In the control group, the Pyr content decreased, at week 4, being one-tenth that of preculture levels. In groups H and M, it was significantly greater than that in groups L and N at week 4. Pyr/hydroxyproline, which indicates the concentration of Pyr per collagen, decreased greatly in the control group at week 3. In groups H and M, it was significantly higher than that in groups L and N at week 4 and increased to 80 and 76% of normal rabbit articular cartilage, respectively. The concentration of Pyr per collagen in cultured chondrocyte-collagen composites was similar to that of normal articular cartilage in vivo, and higher molecular weight HA may have a greater effect on the maturation of collagen in the composite. (c) 2005 Wiley Periodicals, Inc.