title: Distribution of Basement Membrane Molecules, Laminin and Collagen Type IV, in Normal and Degenerated Cartilage Tissues.
abstract: OBJECTIVE
  The objective of the present study was to investigate the presence and distribution of 2 basement membrane (BM) molecules, laminin and collagen type IV, in healthy and degenerative cartilage tissues.
  
  
  METHODS
  Normal and degenerated tissues were obtained from goats and humans, including articular knee cartilage, the intervertebral disc, and meniscus. Normal tissue was also obtained from patella-tibial enthesis in goats. Immunohistochemical analysis was performed using anti-laminin and anti-collagen type IV antibodies. Human and goat skin were used as positive controls. The percentage of cells displaying the pericellular presence of the protein was graded semiquantitatively.
  
  
  RESULTS
  When present, laminin and collagen type IV were exclusively found in the pericellular matrix, and in a discrete layer on the articulating surface of normal articular cartilage. In normal articular (hyaline) cartilage in the human and goat, the proteins were found co-localized pericellularly. In contrast, in human osteoarthritic articular cartilage, collagen type IV but not laminin was found in the pericellular region. Nonpathological fibrocartilaginous tissues from the goat, including the menisci and the enthesis, were also positive for both laminin and collagen type IV pericellularly. In degenerated fibrocartilage, including intervertebral disc, as in degenerated hyaline cartilage only collagen type IV was found pericellularly around chondrocytes but with less intense staining than in non-degenerated tissue. In calcified cartilage, some cells were positive for laminin but not type IV collagen.
  
  
  CONCLUSIONS
  We report differences in expression of the BM molecules, laminin and collagen type IV, in normal and degenerative cartilaginous tissues from adult humans and goats. In degenerative tissues laminin is depleted from the pericellular matrix before collagen type IV. The findings may inform future studies of the processes underlying cartilage degeneration and the functional roles of these 2 extracellular matrix proteins, normally associated with BM.
authors.affiliation: Department of Orthopedics, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA ; Tissue Engineering Labs, VA Boston Healthcare System, Boston, MA, USA ; Orthopaedic Research Laboratory, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Casper Bindzus
authors.initials: CB
authors.lastname: Foldager
authors.affiliation: Department of Orthopedics, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA ; Tissue Engineering Labs, VA Boston Healthcare System, Boston, MA, USA ; Discipline of Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore.
authors.forename: Wei Seong
authors.initials: WS
authors.lastname: Toh
authors.affiliation: Cartilage Repair Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Gomoll
authors.affiliation: Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA.
authors.forename: Bjørn Reino
authors.initials: BR
authors.lastname: Olsen
authors.affiliation: Department of Orthopedics, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA ; Tissue Engineering Labs, VA Boston Healthcare System, Boston, MA, USA.
authors.forename: Myron
authors.initials: M
authors.lastname: Spector
keywords: cartilage; collagen type IV; immunohistochemistry; laminin; pericellular matrix