Bone formation and resorption of highly purified beta-tricalcium phosphate in the rat femoral condyle.
The aim of this study was to examine the chronological histology associated with highly purified beta-tricalcium phosphate (beta-TCP) implanted in the rat femoral condyle. Specimens were harvested on days 4, 7, 14, 28 and 56 after implantation, and were analyzed by tartrate-resistant acid phosphatase (TRAP) staining, immunohistochemistry of the ED1 protein as a marker of the phagocyte system, and in situ hybridization with digoxigenin-labeled alpha1 chain of type I procollagen (COL1A1), osteopontin and osteocalcin. beta-TCP was resorbed in a chronological manner. Although new bone was not observed on day 4, fibroblast-like cells around beta-TCP were positive for COL1A1 and osteopontin mRNA. New bone formation presented after day 7. In the double-staining for OPN and ED1 on day 7, most cells around beta-TCP were positive for either osteopontin mRNA or ED1 protein. However, there were some doubly positive multinucleated cells, suggesting that they belonged to the mononuclear phagocyte system. After day 28, the implanted region was replaced with bone marrow. Multinucleated TRAP-positive and ED1-positive cells which adhered to beta-TCP at all stages seemed to be osteoclasts and they continuously resorbed beta-TCP. beta-TCP has a good biocompatibility since both bioresorption and bone formation started at an early stage after implantation.
Kondo
Naoki
N
Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 757-1, Asahimachi Dori, Niigata 951-8510, Japan.
Ogose
Akira
A
Tokunaga
Kunihiko
K
Ito
Tomoyuki
T
Arai
Katsumitsu
K
Kudo
Naoko
N
Inoue
Hikaru
H
Irie
Hiroyuki
H
Endo
Naoto
N
D020341:Absorbable Implants; D000818:Animals; D001862:Bone Resorption / Q000209:etiology / Q000473:pathology* / Q000517:prevention & control*; D018786:Bone Substitutes / Q000008:administration & dosage; D002130:Calcium Phosphates / Q000008:administration & dosage* / Q000302:isolation & purification; D005260:Female; D005264:Femoral Fractures / Q000150:complications / Q000188:drug therapy* / Q000473:pathology*; D008422:Materials Testing; D010012:Osteogenesis / Q000187:drug effects*; D051381:Rats; D011916:Rats, Inbred F344; D016896:Treatment Outcome
D018786:Bone Substitutes; D002130:Calcium Phosphates; C485817:beta-tricalcium phosphate