TY - JOUR
T1 - Zonal variations in the three-dimensional morphology of the chondron measured in situ using confocal microscopy
AU - Youn, I.
AU - Choi, J. B.
AU - Cao, L.
AU - Setton, L. A.
AU - Guilak, F.
N1 - Funding Information:
Supported by NIH grants AR48182, AR50245, AG15768, and AR47442.
PY - 2006/9
Y1 - 2006/9
N2 - Objective: Chondrocytes in articular cartilage are surrounded by a narrow pericellular matrix (PCM), which together with the enclosed cell(s) are termed the "chondron". Although the precise function of this tissue region is unknown, previous studies provide indirect evidence that the PCM plays an important role in governing the local mechanical environment of chondrocytes. In particular, theoretical models of the chondron under mechanical loading suggest that the shape, size, and biomechanical properties of the PCM significantly influence the stress-strain and fluid flow environment of the cell. The goal of this study was to quantify the three-dimensional morphology of chondron in situ using en bloc immunolabeling of type VI collagen coupled with fluorescence confocal microscopy. Methods: Three-dimensional reconstructions of intact, fluorescently labeled chondrons were made from stacks of confocal images recorded in situ from the superficial, middle, and deep zones of porcine articular cartilage of the medial femoral condyle. Results: Significant variations in the shape, size, and orientation of chondrocytes and chondrons were observed with depth from the tissue surface, revealing flattened discoidal chondrons in the superficial zone, rounded chondrons in the middle zone, and elongated, multicellular chondrons in the deep zone. Conclusions: The shape and orientation of the chondron appear to reflect the local collagen architecture of the interterritorial matrix, which varies significantly with depth. Quantitative measurements of morphology of the chondron and its variation with site, disease, or aging may provide new insights into the influence of this structure on physiology and the pathology of articular cartilage.
AB - Objective: Chondrocytes in articular cartilage are surrounded by a narrow pericellular matrix (PCM), which together with the enclosed cell(s) are termed the "chondron". Although the precise function of this tissue region is unknown, previous studies provide indirect evidence that the PCM plays an important role in governing the local mechanical environment of chondrocytes. In particular, theoretical models of the chondron under mechanical loading suggest that the shape, size, and biomechanical properties of the PCM significantly influence the stress-strain and fluid flow environment of the cell. The goal of this study was to quantify the three-dimensional morphology of chondron in situ using en bloc immunolabeling of type VI collagen coupled with fluorescence confocal microscopy. Methods: Three-dimensional reconstructions of intact, fluorescently labeled chondrons were made from stacks of confocal images recorded in situ from the superficial, middle, and deep zones of porcine articular cartilage of the medial femoral condyle. Results: Significant variations in the shape, size, and orientation of chondrocytes and chondrons were observed with depth from the tissue surface, revealing flattened discoidal chondrons in the superficial zone, rounded chondrons in the middle zone, and elongated, multicellular chondrons in the deep zone. Conclusions: The shape and orientation of the chondron appear to reflect the local collagen architecture of the interterritorial matrix, which varies significantly with depth. Quantitative measurements of morphology of the chondron and its variation with site, disease, or aging may provide new insights into the influence of this structure on physiology and the pathology of articular cartilage.
KW - Articular cartilage
KW - Chondrocyte
KW - Collagen
KW - Extracellular matrix
KW - Immunohistochemistry
KW - Pericellular matrix
KW - Three-dimensional reconstruction
KW - Type VI collagen
UR - http://www.scopus.com/inward/record.url?scp=33746509137&partnerID=8YFLogxK
U2 - 10.1016/j.joca.2006.02.017
DO - 10.1016/j.joca.2006.02.017
M3 - Article
C2 - 16626979
AN - SCOPUS:33746509137
SN - 1063-4584
VL - 14
SP - 889
EP - 897
JO - Osteoarthritis and Cartilage
JF - Osteoarthritis and Cartilage
IS - 9
ER -