Bone density in old chickens' metaphyses, as affected by local trauma and chondrocyte implantation.
Resurfacing of joints by chondrocyte implants often leads to an increased subchondral bone density. To further evaluate this phenomenon, this study analyzed bone density and bone formation in three groups of 3-year-old chickens (90 animals, 30 per group): (1) implantation of chondrocytes embedded in hyaluronic acid (HA) into the tibial metaphysis; (2) implantation of delivery substance only; (3) sham-operated control group. Results were assessed biochemically, histologically, and histomorphometrically at 6 weeks and 6 months postimplantation. A 1.5-fold increase in the metaphyseal bone density was observed in the HA-implanted controls, as compared to sham-operated/normal joints. A further increase in bone density to twice the density of the sham-operated joints was achieved by implantation of chondrocytes. In bones implanted with cells, long-lasting (6 weeks) cartilage nodules were observed, which eventually underwent hypertrophy. The implanted chondrocytes were surrounded by a dense inflammatory infiltrate, which did not prevent the induction and formation of new bone. Based on these findings, it was concluded that chondrocyte implantation into bones results in an increase in local bone density due to a prolonged process of endochondral ossification. Further studies are necessary to evaluate the possible application of this implantation procedure in osteoporosis.
Department of Orthopaedic Surgery, Assaf Harofeh Medical Center, Zeriffin.
D
D
Robinson
N
N
Halperin
Z
Z
Nevo
D000818:Animals; D015519:Bone Density; D001846:Bone Development; D002356:Cartilage / Q000166:cytology*; D002358:Cartilage, Articular / Q000502:physiology*; D002645:Chickens; D005260:Female; D006820:Hyaluronic Acid; D014677:Pharmaceutical Vehicles; D012038:Regeneration; D013977:Tibia / Q000166:cytology / Q000601:surgery
D014677:Pharmaceutical Vehicles; D006820:Hyaluronic Acid