title: Changes in gene expression associated with matrix turnover, chondrocyte proliferation and hypertrophy in the bovine growth plate.
abstract: The aim of the study is to investigate the interrelationships between the expression of genes for structural extracellular matrix molecules, proteinases and their inhibitors in the bovine fetal growth plate. This was analyzed by RT-PCR in microsections of the proximal tibial growth plate of bovine fetuses in relationship to expression of genes associated with chondrocyte proliferation, apoptosis, and matrix vascularization. In the resting zone the genes for extracellular matrix molecule synthesis were expressed. Extracellular matrix degrading enzymes and their inhibitors were also expressed here. Onset of proliferation involved cyclic upregulation of cell division-associated activity and reduced expression of extracellular matrix molecules. Later in the proliferative zone we noted transient expression of proteinases and their inhibitors, extracellular matrix molecules, as well as activity associated with vascularization and apoptosis. With the onset of hypertrophy expression of proteinases and their inhibitors, extracellular matrix molecules, as well as activity associated with vascularization and apoptosis were significantly upregulated. Terminal differentiation was characterized by high expression of proteinases and their inhibitors, extracellular matrix molecules, as well as activity associated with apoptosis. This study reveals the complex interrelationships of gene expression in the physis that accompany matrix assembly, resorption, chondrocyte proliferation, hypertrophy, vascularization and cell death while principal zones of the growth plate are characterized by a distinct signature profile of gene expression.
authors.affiliation: Clinical Immunology Department, Research Institute of Rheumatology, Russian Academy of Sciences, Moscow, 115522, Russia.
authors.forename: E V
authors.initials: EV
authors.lastname: Tchetina
authors.affiliation: Orthopaedics Research Laboratory, Jewish General Hospital, Lady Davis Institute for Medical Research, Division of Orthopedic Surgery, McGill University, Montreal, Quebec, H3T 1E2, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Mwale
authors.affiliation: Department of Surgery, McGill University, McGill University, Montreal, Quebec, H3A 0G4, Canada.
authors.forename: A R
authors.initials: AR
authors.lastname: Poole
keywords: chondrocyte differentiation; gene expression; growth plate; proteinases