Parathyroid hormone-related peptide and indian hedgehog expression patterns in naturally acquired equine osteochondrosis.

TitleParathyroid hormone-related peptide and indian hedgehog expression patterns in naturally acquired equine osteochondrosis.
Publication TypeJournal Article
Year of Publication2002
AuthorsSemevolos SA, Brower-Toland BD, Bent SJ, Nixon AJ
JournalJournal of orthopaedic research : official publication of the Orthopaedic Research Society
Volume20
Issue6
Pagination1290-7
Date Published2002 Nov
ISSN0736-0266
KeywordsAnimals, Cartilage, Articular, Disease Models, Animal, Gene Expression, Hedgehog Proteins, Horse Diseases, Horses, Hypertrophy, Osteochondritis, Osteochondrodysplasias, Parathyroid Hormone-Related Protein, Peptide Hormones, RNA, Messenger, Trans-Activators
Abstract

Early changes in parathyroid hormone-related peptide (PTH-rP) and Indian hedgehog (Ihh) expression were examined in equine articular osteochondrosis (OC) as a model of a naturally acquired dyschondroplasia. Cartilage was harvested from OC-affected femoropatellar or scapulohumeral joints from immature horses and normal control horses of similar age. PTH-rP expression levels were assessed by semi-quantitative PCR, in situ hybridization, and immunohistochemistry. Ihh protein expression levels were assessed by immunohistochemistry. Elevated PTH-rP protein and mRNA expression were identified in the deeper layers of affected articular cartilage and the fibrous tissue of interposing clefts. These changes were confined to the chondrocytes in the OC-affected cartilage, which had significantly increased PTH-rP protein and mRNA expression when compared to control cartilages. Ihh protein expression showed similar distribution as PTH-rP in the deeper layers of articular cartilage; however, only a trend for increased Ihh immunostaining was evident in the OC cartilage when compared to the normal cartilage. Increased PTH-rP expression in prehypertrophic chondrocytes of diseased OC cartilage suggests a possible link between this peptide and the delayed ossification, which is a consistent histologic alteration in OC. More evidence is necessary to determine the role of Ihh in articular cartilage and if a similar feedback cycle exists as previously described for the growth plate.

DOI10.1016/S0736-0266(02)00055-4
Alternate JournalJ. Orthop. Res.