The role of mesenchyme in embryonic long bones as early deposition site for osteoclast progenitor cells

Osteoclast formation from mononuclear phagocytes: role of bone-forming cells.

“…A descendance from the stripped rudiment itself is highly unlikely, in view of the absence of cartilage labeling in the autoradiographs and the absence of osteoclast formation in live, stripped bones cultured without added cells. Quail mouse chimera studies, which made use of the specific nuclear morphology of quail cells as marker, have led to a similar conclusion (4). The finding of a higher labeling index of osteoclast nuclei than of co-cultured mononuclear phagocytes is remarkable and may indicate that osteoclasts are selectively derived from the proliferating fraction of the BMMP population.…”

“…The next day the metatarsal rudiments of the 17-d-old fetuses were dissected and rigorously stripped of adhering periehondrium-pefiosteum by a combination of collagenase and mechanical treatment until all periosteal cells had been removed. As the 17-d-old metatarsal rudiments had not yet been invaded by blood vessels or any type of mononuclear or multinuclear cells, the stripped rudiments only consisted of a solid rod of cartilage (two noncalcified epiphyses and a diaphysis of noninvaded calcified cartilage without a primitive marrow cavity) surrounded by a thin layer of bone matrix with a few osteocytes (3,4). Some of the stripped bones were killed by repeated freezing and thawing and subsequently severed in the center to expose the calcified cartilage as well as the calcified bone collar.…”

“…In an earlier paper we presented evidence that multinucleated mineral resorbing osteoclasts will develop in vitro from cultures of proliferating bone marrow mononuclear phagocytes (BMMP) ~ (3). This was demonstrated by co-culturing adult mouse BMMP with noninvaded embryonic mouse long bones that had been stripped of adhering periosteum-perichondrium to remove the endogenous pool of osteoclast precursor cells (4). As the bones were dissected and stripped before cartilage invasion and osteoclast formation had occurred, the stripped bone rudiments essentially contained only chondrocytes and Abbreviations used in this paper."…”

Skin inhibits cartilage proliferation and calcification Tissue culture of fetal mice bones

“…We think, however, that it is unlikely that the observed effects were all caused by such factors. The amount of medium we used can support the normal growth of six metatarsal bones and soft-tissue fragments (Thesingh & Burger 1983): all tissues had normal histology, and there were no differences between the muscle group and the control group, even though the 38 muscle fragments were larger than the skin fragments.…”

Culture of Murine Embryonic Metatarsals: A Physiological Model of Endochondral Ossification

“…The mouse metatarsal organ explant culture, pioneered by Prof. Elisabeth Burger and colleagues in the Netherlands, is a highly physiological ex vivo model for studying endochondral ossification and bone growth as the growth rate of the bones in culture mimic that seen in vivo 18 . Uniquely, the metatarsal organ culture allows the examination of chondrocytes in different phases of chondrogenesis and maintains cell-cell and cellmatrix interactions, therefore providing conditions closer to the in vivo situation than cells in culture [19][20][21] .…”