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In situ expression of collagen and proteoglycan genes during development of fibrocartilage in bovine deep flexor tendon
Author(s) -
PerezCastro Ana V.,
Vogel Kathryn G.
Publication year - 1999
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.1100170120
Subject(s) - fibrocartilage , decorin , aggrecan , tendon , biglycan , anatomy , type i collagen , type ii collagen , in situ hybridization , enthesis , microbiology and biotechnology , proteoglycan , chemistry , cartilage , biology , pathology , gene expression , medicine , osteoarthritis , gene , articular cartilage , biochemistry , alternative medicine
Abstract A region of fibrocartilage develops in bovine deep flexor tendon where the tissue wraps around bone and is subjected to compressive and shear forces in addition to tension. There is no fibrocartilage at this location in fetal tendon or in adjacent adult tendon that is subjected to tensional load only. We investigated the development of fibrocartilage in tendon using in situ hybridization to localize cells that express collagen and proteoglycan genes typical of either tendon or cartilage. The signal for type I collagen and decorin was high in cells throughout fetal and newborn tendon, as is expected in a growing tissue composed predominantly of type I collagen. No signal for aggrecan was seen in either fetal or newborn tendon. No hybridization with any of the probes for collagen or proteoglycan was detected in cells in the tensional region of adult tendon, indicating that the cells in this tissue are normally quiescent. However, the cells in the fibrocartilage of adult tendon displayed a high level of expression for types I and II collagen, decorin, biglycan, and aggrecan. This suggests that the fibrocartilage in adult tendon is a dynamic tissue. Expression of type IIA collagen is considered a marker of prechondrocytes. Type IIA collagen gene expression was present throughout both the tensional and compressed regions of fetal and newborn tendon but was absent in cartilaga and adult tendon. This suggests that cells located throught fetal tendon may have the capacity to develop as chondrocytes. Fibrocartilage signal was detected for type I collagen in 75% of the cells and for type II collagen in 50% of the cells at one location in adult tendon, suggesting that some cells in this tissue could have expressed mRNA for both type I and type II collagen.