Characterization of developing antler cartilage matrix. I. Selected histochemical and enzymatic assessment.

Biopsy samples of the main beams and tines were obtained from the antlers of mature Rocky Mountain mule deer (Odocoileus hemionus hemionus) during the rapid phase of the antler grow-th cycle. The samples were studied using histochemical and enzymatic techniques for the demonstration of mucosubstances. The reserve mesenchyme contained chondroitin 4- and 6-sulfates, hyaluronic acid and sialic acid. During prechondroblastic and chondroblastic differentiation, some strongly sulfated mucopolysaccharides were complemented by low molecular weight or incompletely sulfated chondroitin 4- and 6-sulfates. During maturation of the cartilage strongly anionic mucopolysaccharides (possibly heparin, keratan and/or dermatan sulfates) were present in the general matrix and especially prominent along the capsular margins. Calcification foci, beginning initially in the mid-trabecular regions and eventually extending to the trabecular margins, were highly reactive for mucosubstances and were enzyme-resistant. This histochemical study establishes the cartilaginous nature of the developing deer antler, defines some of the mucosubstance constituents involved in the chondrogenic and calcification process, and confirms the utility of the antler as a model for chondrogenic and calcification studies.