The effects of tensile load on the metabolism of cultured chondrocytes.

The effect of cyclic tensile load on articular cartilage metabolism was investigated experimentally using 12 Japanese White rabbits. Chondrocytes obtained from the knee joints were cultured on plates with flexible silicone rubber bases. They were subjected to a cyclic (3 seconds on and 3 seconds off) tensile load for 24 hours with a maximum increase in area of 17%. Proteoglycan synthesis, collagen synthesis, and tissue inhibitors of metalloproteinases production by the chondrocytes under the load were quantified and compared with those produced by the control cells in an unloaded condition. The cultured chondrocytes under the cyclic tensile load perpendicularly aligned to the direction of the tensile load. Collagen synthesis and tissue inhibitors of metalloproteinases production increased significantly under the cyclic tensile load, although no significant change in proteoglycan synthesis was observed. These results suggested that the cyclic tensile load on the chondrocytes contribute to the regulation of articular cartilage metabolism in part.