Chondroclasts in osteoneogenesis

Abstract Allogenic, demineralized bone powder (DBP) was implanted into rat rectus abdominis muscle to induce Osteoneogenesis. The main induction steps are invasion of the implant by host mesenchyme cells, differentiation of cartilage, invasion by blood capillaries or angiogenesis, differentiation of osteoblasts and bone marrow. The result is the formation of a cancellous ossicle. Giant polykarions appear in the implant after calcification of the cartilage matrix. As the DBP particles are not resorbed in the implant, these polykarions could either be foreign body giant cells brought about in reaction to foreign matrix or chondroclasts which resorb the cartilage. The results obtained by histological and histochemical methods (McNealsvon Kossa stain, tartrate resistant acid phosphatase reaction), as well as ultrastructural studies, lead to the conclusion that these large polynucleated cells are chondroclasts.