A correlative immuno-light and electron microscopic study on the type I collagen in the bone morphogenetic protein-induced cartilage.
Bone morphogenetic protein (BMP) partially purified from bovine bone was implanted into the thigh muscles of AKR-strain mice to induce an ectopic endochondral ossification tissue. The extracellular matrix components around the hypertrophic chondrocytes in the induced tissue were examined by electron microscopy and immunohistochemistry for type I collagen. At 14 days after implantation, chondrocytes became hypertrophic with calcifying matrix around them. Some hypertrophic chondrocytes showed no degenerative appearances. They were ringed by a pericellular matrix with no metachromasia which was distinct from the metachromatic cartilage matrix. The localization of type I collagen was demonstrated by immuno-staining in this matrix. Ultrastructurally, ring-shaped matrix consisted of interwoven collagen fibrils on which a D-periodic banding pattern could be discerned. Immunoelectron microscopy demonstrated immunoreactivity of type I collagen on these fibrils. These results suggest that some of the BMP-induced hypertrophic chondrocytes maintain their activity and produce type I collagen-rich matrix before their lacunae are eroded.
Hattori
H
H
Department of Oral Surgery, Nagoya University School of Medicine, Japan.
Kawai
M
M
Yasue
K
K
Mizutani
H
H
Kobayashi
M
M
Kaneda
T
T
Hoshino
T
T
D000818:Animals; D019485:Bone Morphogenetic Proteins; D002356:Cartilage / Q000737:chemistry* / Q000187:drug effects / Q000648:ultrastructure; D003094:Collagen / Q000032:analysis*; D005109:Extracellular Matrix / Q000737:chemistry / Q000648:ultrastructure; D008297:Male; D051379:Mice; D008806:Mice, Inbred AKR; D016253:Microscopy, Immunoelectron; D009999:Ossification, Heterotopic / Q000139:chemically induced*; D011506:Proteins / Q000494:pharmacology*
D019485:Bone Morphogenetic Proteins; D011506:Proteins; D003094:Collagen