Microscopic studies of achondroplastic rabbit cartilage

Abstract The cartilage of long bones in newborn achondroplastic (ac/ac) dwarf rabbits was compared with that of phenotypically normal littermates using histologic, histochemical, and electron‐microscopic procedures. The dwarf cartilages contained (1) dead chondrocytes (nuclear pyknosis and absence of surrounding moat) distributed with increasing frequency from the periphery to the center of the resting cartilage (littermate controls showed far fewer and a random distribution of dead chondrocytes); (2) fewer chondrocytes in the isogenous groups or capsules of central portion of the metaphyseal growth plate compared to controls; and (3) less cartilage matrix. Based on these observations it is suggested that a metabolic defect may become expressed specifically in achondroplastic cartilage cells when they are isolated from their vascular supply.