title: Expression of chondro-osteogenic BMPs in ossified failed tendon healing model of tendinopathy.
abstract: Chondrocytes phenotype/markers were expressed in clinical samples of tendinopathy and calcifying tendinopathy. This study examined the spatial-temporal expression of chondro-osteogenic Bone Morphogenetic Proteins (BMPs), which might contribute to ectopic chondro-osteogenesis and failed healing process in tendinopathy. Collagenase was injected into patellar tendon of rats to induce ossified failed tendon healing. At week 2, 4, 8, 12, and 16, the patella tendon was harvested for immunohistochemical staining and analysis of BMP-2/4/7. BMP-4/7 showed similar expression patterns, which was different from BMP-2. The expression of BMP-2 in the tendon matrix increased at week 2 and was reduced to nearly undetectable level afterwards except at the chondro-ossification sites. However, the expression of BMP-4/7 in the healing tendon fibroblast-like cells and matrix increased at week 2, reduced at week 4 and 8 and increased again at week 12 and 16, consistent with transient healing at week 8 in this animal model. There was increasing strong expression of BMP-4/7 in the chondrocyte-like cells in the un-ossified and ossified areas from week 8-16. BMP-4/7, besides BMP-2, might also contribute to ectopic chondro-osteogenesis and failed healing in tendon injuries. BMP-4/7, but not BMP-2, might be involved in regulating late events in ossified failed tendon healing.
authors.affiliation: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR, China. pauline@ort.cuhk.edu.hk
authors.forename: Pauline Po
authors.initials: PP
authors.lastname: Yee Lui
authors.forename: Yin Mei
authors.initials: YM
authors.lastname: Wong
authors.forename: Yun Feng
authors.initials: YF
authors.lastname: Rui
authors.forename: Yuk Wa
authors.initials: YW
authors.lastname: Lee
authors.forename: Lai Shan
authors.initials: LS
authors.lastname: Chan
authors.forename: Kai Ming
authors.initials: KM
authors.lastname: Chan
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002114:Calcinosis / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D052256:Tendinopathy / Q000378:metabolism*
chemical_list: D019485:Bone Morphogenetic Proteins