Electron Microscopy of Cartilage Resorption by Chondroclasts

¹ Department of Pathology, Tokyo Dental College, Kanda-Misakicho, Chiyoda-ku, Tokyo

Cartilage resorption by the chondroclasts that appears during the intracartilagenous bone formation in the phalanges of young mice was studied with the electron microscope.

The occurrence of the cartilage matrix fibrils denuded of crystals, as well as free crystals liberated from the matrix, were indicated in the chondroclasts and at the edge of the resorbing cartilage. A remarkable increase in the electron density of the cartilage was consistently observed beneath the area that had been changed into a porous structure because of active resorption. This increased density was suggested to be the result of an alteration in the organic matrix of the cartilage.