Characterisation of pre-osseus tissues in the antlers of red deer (cervus elaphus)
Abstract (summary)
As part of the characterisation of the developmental process in the pre-osseus tissues of the antler, the spatial expression of mRNAs for collagen types I, IIA, IIB, and the cartilage-specific proteoglycan aggrecan, was studied by in situ hybridisation. Type I procollagen messenger RNA (mRNA) was expressed by mesenchymal cells, chondroprogenitors and a cell population in the cartilage zone that was distinct from the differentiated chondrocytes. mRNA transcripts for both isoforms of type II collagen, types IIA and IIB, and for the core protein of aggrecan were expressed in chondrocytes in the developing antler tip. The distribution of type X collagen was shown to be more extensive than in other models of chondrogenesis; synthesis was initiated in recently differentiating chondrocytes away from the calcifying matrix, which raises intriguing questions as to the function of this molecule. These data indicate that distinct and temporal patterns of extracellular matrix gene expression during antler growth resemble, in part, those observed during chondrogenesis in other mammalian models.
The studies described in this thesis have partially characterised the pre-osseus tissues of the developing antler, and suggest that this is a potentially useful model for the study of normal and pathological bone growth. The data presented provide the foundation for future studies of how this accelerated bone growth may be regulated.