Effect of pressure on bone resorption

Abstract

Laminaria, a hygroscopic seaweed material, was capable of absorbing fluid, and gradually swelled up to four times its diameter within 24 hours. Laminaria was used to induce pressure within the rat tympanic cavity. Resorption of bulla and cochlear walls occurred in all animals within two weeks. Preswelled laminaria inserted in the same area induced minimal bone resorption after two and three weeks. We also studied the effect of indomethacin, a specific inhibitor of prostaglandin synthesis, on bone resorption induced by physical force. In animals given indomethacine following insertion of laminaria, both granulation tissue formation and bone resorption were inhibited. Acid phosphatase activity appeared localized in the inflammatory granulation tissue in the bone resorption area, especially in osteoclasts, mononuclear cells and fibroblasts. Results of this study suggested that pressure created by laminaria caused bone resorption by stimulating osteoclasts and granulation tissue through biochemichal events. Pressure did not cause bone resorption directly.