The effect of mechanical stress on cultured growth cartilage cells.

Mechanical stress seems to influence the growth of bone, but little is known about the transduction of mechanical forces into biochemical signals. The present study was done to resolve the important question of how a mechanical stimulus is transduced into a metabolic response by chondrocytes. Cultured growth cartilage cells isolated from rat ribs and subjected to mechanical stress (tensile force) showed a significant increase in intracellular cyclic AMP levels, but no increase in prostaglandin E2 levels. In glycosaminoglycan synthesis measured by radioactive sulfate incorporation, long-term exposure of chondrocytes to mechanical loading caused increased synthesis. Moreover, long-term exposure of chondrocytes exerted an alteration of responsiveness to parathyroid hormone and calcitonin measured as intracellular cyclic AMP content. These results suggest that mechanical stress can alter bone growth by modulating the metabolism of growth cartilage cells.