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 x10(6) Da (group H), 8.0 x10(5) Da (group M), and 2.3 x10(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.