Effect of partial hydrolysis of octacalcium phosphate on its osteoconductive characteristics.
The present study was designed to investigate whether the stoichiometry of octacalcium phosphate OCP affects its osteoconductive and immune response characteristics in rat bone marrow. Those characteristics of synthetic, well-grown OCP but with a non-stoichiometric composition were compared with those of a slightly hydrolyzed OCP (low crystalline OCP: LC-OCP), the fully hydrolyzed apatitic product of OCP or biodegradable beta-tricalcium phosphate (beta-TCP) ceramic, by their implantation in rat tibia for 56 days. The physicochemical aspect of implants and biological responses were analyzed by X-ray diffraction, histomorphometry, immunohistochemistry and expression of mRNA around the implants. The remarkable findings were that: (1) the highest bone formation rate was obtained for beta-TCP whereas the lowest for LC-OCP at Day 14; (2) the rates were reversed and reached the highest for LC-OCP until Day 56; (3) the early expression of ostoeoclast markers TRAP and cathepsin-K was suppressed with LC-OCP; (4) the expression of inflammatory markers IL-beta1 and TNF-alpha was suppressed with LC-OCP. The results confirmed that the partially hydrolyzed OCP with Ca/P molar ratio 1.37 (LC-OCP) enhances bone formation most, suppressing early osteoclast activity and reducing inflammation.
Miyatake
Naohisa
N
Department of Orthopedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seriyo-machi, Aoba-ku, Sendai 980-8574, Japan.
Kishimoto
Koshi N
KN
Anada
Takahisa
T
Imaizumi
Hideki
H
Itoi
Eiji
E
Suzuki
Osamu
O
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects*; D002130:Calcium Phosphates / Q000378:metabolism* / Q000494:pharmacology*; D003460:Crystallization; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D006868:Hydrolysis / Q000187:drug effects; D007150:Immunohistochemistry; D020007:Implants, Experimental; D018836:Inflammation Mediators / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D015675:Osteocalcin / Q000378:metabolism; D010010:Osteoclasts / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects; D053495:Osteopontin / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013499:Surface Properties / Q000187:drug effects; D000071681:Tartrate-Resistant Acid Phosphatase; D013977:Tibia / Q000002:abnormalities / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D013997:Time Factors
D002130:Calcium Phosphates; D016207:Cytokines; D018836:Inflammation Mediators; D007527:Isoenzymes; D012333:RNA, Messenger; C485817:beta-tricalcium phosphate; D015675:Osteocalcin; D053495:Osteopontin; C022045:octacalcium phosphate; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase