Transgenic mouse models for studying the role of cartilage macromolecules in osteoarthritis

The development of transgenic technology has made possible thegeneration of targeted gene-mutated mouse lines suitable foruse in experimental osteoarthritis (OA) research. Transgenicmice harbouring mutations in cartilage collagen types II andIX develop early-onset OA and are therefore promising modelsof age-related OA, even though the mice often show signs ofchondrodysplasia. Also, mouse lines harbouring other engineeredmutations of the extracellular molecules have given rise toearly OA. The molecular background of a few spontaneous mutationsin mice has also been clarified and the characterization ofthe OA phenotype is now in progress. These mutations cause severechondrodysplasia and death in homozygous mice, but the heterozygousoffspring develop the early-onset OA phenotype. Correspondence to: H. J. Helminen, Department of Anatomy, Universityof Kuopio, PO Box 1627, FIN-70211 Kuopio, Finland.