Developmental failure of the intra-articular ligaments in mice with absence of growth differentiation factor 5

Objective: To show the phenotypic characteristics of the knee joints in brachypodism mice (bp mice), which carry a functional null mutation of the growth differentiation factor 5 (GDF5) gene, we investigated the adult and embryonic by mice. Method: Radiographic and macroscopic examinations of the knee joint of adult by mice were performed. A histological examination of the knee joint of by mice from E12.5 to E18.5 was also performed. Results: Radiographic and macroscopic examinations of the adult by mice showed anterior dislocation, hypoplastic condyles, and absence of the intra-articular ligaments. Safranin O staining of knee joints of the embryonic by mice showed severe hypoplasty of the chondroepiphyses and intra-articular ligaments at E16.5. There was no difference in the number and location of 5-bromo-2'-deoxyuridine (BrdU)-positive cells between wild-type and by mice through E12.5 to E14.5. A terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL) study showed excessive cell death of mesenchymal cells of the future knee joint in by mice at E12.5 and E13.5. Conclusion: by mice exhibit developmental failure of the condyles and intra-articular ligament of the knee joints. (C) 2006 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.