title: Knee joint immobility induces Mcl-1 gene expression in articular chondrocytes.
abstract: The capacity of chondrocytes to synthesize and remodel the extracellular matrix of the articular cartilage is influenced by mechanical forces applied to joints. Either abnormally high or low loads are detrimental to articular cartilage. Experimental work on animals suggests that immobilization can alter proteoglycan synthesis and result in thinning and softening of the articular cartilage. Little is known of the effects of joint immobility on the pattern of genes expressed by chondrocytes. This study focused on the induction of Mcl-1 gene expression in a rat model of knee joint immobilization by the method of differential display PCR. Increase in Mcl-1 gene expression in chondrocytes induced by joint immobilization was confirmed by RT-PCR, Northern blotting, and immunohistochemistry. Our results indicate that chondrocytes respond to the complete absence of joint motion by expressing Mcl-1 gene. This expression may be part of a defense strategy by chondrocytes to overcome the impending chondrocyte death and cartilage degeneration induced by joint immobility.
authors.affiliation: Bone and Joint Research Laboratory, Department of Medicine, Faculty of Medicine, University of Ottawa, ON, Canada.
authors.forename: G
authors.initials: G
authors.lastname: Trudel
authors.forename: H
authors.initials: H
authors.lastname: Uhthoff
authors.forename: O
authors.initials: O
authors.lastname: Laneuville
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism*; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology*; D007103:Immobilization / Q000379:methods*; D007719:Knee Joint / Q000378:metabolism*; D008297:Male; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2