Cellular responses of embryonic hyaline cartilage to experimental wounding in vitro

Abstract

It is well established that thc rcparativc potential of many tissues is greatest during embryonic development. Despite the extensive literature documenting repair in nonembryonic cartilage models, there is no cornparablc wealth of experience relating to embryonic cartilage repair. With the embryonic chick sternum as a model of hyaline cartilagc. this paper accounts cellular responses arid alterations in extracellular matrix composition in response Lo cxpcrimental wounding in virro. Creation of an experimental lesion induced a rapid (<20 minutes) apoptolic response in chondrocytes adjacent to the lesion edge; the presence of perichondrium delayed this response. Alteralions in thc cxtracellular matrix included immediate mechanical damage to type-TI collagen fibrils and an increase in the expression of chondroitin-4 sulphate next to the lesion. Creation of the lesion induced an increased proliferative response in chondrocytes behind the zone of apoptosis and lhe expression of u5 and a6 integrin subunits. © 2000 Orthopaedic Research Society.