title: Evaluation of the osteoconductivity of α-tricalcium phosphate, β-tricalcium phosphate, and hydroxyapatite combined with or without simvastatin in rat calvarial defect.
abstract: The purpose of this study is to evaluate the osteoconductivity of three different bone substitute materials: α-tricalcium phosphate (α-TCP), (β-TCP), and hydroxyapatite (HA), combined with or without simvastatin, which is a cholesterol synthesis inhibitor stimulating BMP-2 expression in osteoblasts. We used 72 Wistar rats and prepared two calvarial bone defects of 5 mm diameter in each rat. Defects were filled with the particles of 500-750 μm diameter combined with or without simvastatin at 0.1 mg dose for each defect. In the control group, defects were left empty. Animals were divided into seven groups: α-TCP, β-TCP, HA, α-TCP with simvastatin, β-TCP with simvastatin, HA with simvastatin, and control. The animals were sacrificed at 6 and 8 weeks. The calvariae were dissected out and analyzed with micro CT. The specimens were evaluated histologically and histomorphometrically. In α-TCP group, the amount of newly formed bone was significantly more than both HA and control groups but not significantly yet more than β-TCP group. Degradation of α-TCP was prominent and β-TCP showed slower rate while HA showed the least degradation. Combining the materials with Simvastatin led to increasing in the amount of newly formed bone. These results confirmed that α-TCP, β-TCP, and HA are osteoconductive materials acting as space maintainer for bone formation and that combining these materials with simvastatin stimulates bone regeneration and it also affects degradability of α-TCP and β-TCP. Conclusively, α-TCP has the advantage of higher rate of degradation allowing the more bone formation and combining α-TCP with simvastatin enhances this property.
authors.affiliation: Oral Implantology and Regenerative Dental Medicine, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo 113-8549, Japan. hisham.rojbani@gmail.com
authors.forename: Hisham
authors.initials: H
authors.lastname: Rojbani
authors.forename: Myat
authors.initials: M
authors.lastname: Nyan
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ohya
authors.forename: Shohei
authors.initials: S
authors.lastname: Kasugai
mesh_terms: D000818:Animals; D000924:Anticholesteremic Agents / Q000737:chemistry / Q000494:pharmacology; D001672:Biocompatible Materials / Q000737:chemistry / Q000494:pharmacology; D001861:Bone Regeneration / Q000187:drug effects*; D018786:Bone Substitutes / Q000494:pharmacology*; D002130:Calcium Phosphates / Q000737:chemistry / Q000494:pharmacology*; D004337:Drug Carriers / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D020007:Implants, Experimental; D008297:Male; D008422:Materials Testing; D051381:Rats; D017208:Rats, Wistar; D019821:Simvastatin / Q000737:chemistry / Q000494:pharmacology*; D012886:Skull / Q000187:drug effects / Q000473:pathology* / Q000502:physiology; D015898:Tomography Scanners, X-Ray Computed
chemical_list: D000924:Anticholesteremic Agents; D001672:Biocompatible Materials; D018786:Bone Substitutes; D002130:Calcium Phosphates; D004337:Drug Carriers; C485828:alpha-tricalcium phosphate; C485817:beta-tricalcium phosphate; D017886:Durapatite; D019821:Simvastatin