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Characterization of the development of ectopic chondroid/bone matrix and chondrogenic/osteogenic cells during osteoinduction by rhBMP‐2: a histochemical and ultrastructural study
Author(s) -
Nakagawa T,
Sugiyama T,
Shimizu K,
Murata T,
Narita M,
Nakamura S,
Tagawa T
Publication year - 2003
Publication title -
oral diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.953
H-Index - 87
eISSN - 1601-0825
pISSN - 1354-523X
DOI - 10.1034/j.1601-0825.2003.02912.x
Subject(s) - endochondral ossification , bone morphogenetic protein , chemistry , chondrogenesis , alkaline phosphatase , cartilage , matrix (chemical analysis) , bone morphogenetic protein 2 , demineralized bone matrix , type i collagen , anatomy , type ii collagen , microbiology and biotechnology , pathology , biology , materials science , dbm , biochemistry , in vitro , medicine , amplifier , optoelectronics , cmos , chromatography , gene , enzyme
Objective: To investigate the characteristics of ectopic chondroid/bone matrix and chondrogenic/osteogenic cells induced by recombinant human bone morphogenetic protein‐2 (rhBMP‐2). Materials and methods: rhBMP‐2 (5 μ g) combined with atelocollagen was implanted into calf muscles of rats and removed on days 7, 10, 14, 21, or 28. Tissue sections were examined using: (i) hematoxylin/Alcian blue/Sirius red stain, (ii) enzyme histochemistry for alkaline phosphatase (ALP) and tartrate‐resistant acid phosphatase activity, (iii) immunohistochemistry for types I, II, and X collagen, and (iv) electron microscopy. Results: On day 7, numerous fibroblast‐like cells with ALP activity were present on the pellet rim. On day 10, chondroid matrix (CM) had formed, contained both type I collagen and proteoglycans, and often continued into the BMP pellet. On day 14, bone‐like matrix formed around hypertrophic chondrocytes simultaneously with endochondral ossification. Coexpression of types I and II collagen within chondrocytes and osteocytes was observed throughout the time course of the experiment. Conclusion: These results suggest that fibroblast‐like cells invading the pellet differentiate into chondrocytes and form CM under the scaffold of the carrier component. It appears that some chondrocytes change their phenotype to produce the bone‐like matrix and remain within the endochondral bone. This process enables rapid osteogenesis to occur.