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Matrix metalloproteinase‐9 expression, tartrate‐resistant acid phosphatase activity, and DNA fragmentation in vascular and cellular invasion into cartilage preceding primary endochondral ossification in long bones
Author(s) -
Takahara Masatoshi,
Naruse Takuji,
Takagi Michiaki,
Orui Hiroshi,
Ogino Toshihiko
Publication year - 2004
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 - 10.1016/j.orthres.2004.01.011
Subject(s) - endochondral ossification , cartilage , angiogenesis , matrix metalloproteinase , biology , pathology , cd31 , microbiology and biotechnology , chemistry , anatomy , medicine , cancer research , biochemistry
Vascular and cellular invasion into cartilage are essential for endochondral ossification. Recently it has been shown that matrix metalloproteinase‐9 (MMP‐9)/gelatinase B is a key regulator of growth plate angiogenesis and apoptosis of hypertrophic chondrocytes. To study vascular and cellular invasion into cartilage preceding primary endochondral ossification in long bones, precursor femurs from 13‐ to 16‐day‐old murine embryos were sectioned. Tartrate‐resistant acid phosphatase (TRAP) activity, in situ hybridization for matrix metalloproteinase‐9 (MMP‐9), immunostaining for CD31, and in situ detection of apoptosis (TUNEL) were studied. TRAP activity, MMP‐9 mRNA, and CD31 expression were initially detected in the intertrabecular spaces of the perichondral collar, and then in cells migrating into the cartilage. The first cells involved in the primary invasion into cartilage were CD31‐positive vascular endothelial cells and MMP‐9‐positive cells, followed by TRAP‐positive cells. At the cartilage‐marrow interface, CD31‐positive vascular endothelial cells and MMP‐9‐positive cells were predominant. These results suggest that MMP‐9‐positive cells cooperate with vascular endothelial cells in cartilage angiogenesis. TUNEL‐positive staining was detected on chondrocytes attached to the inner surface of the perichondral collar, and also detected in the area where cartilage was removed. These results suggest that chondrocytes separated from the cartilage matrix may undergo apoptosis. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.