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.

Evaluation of Bone Regeneration by porous Alpha-Tricalcium Phosphate/Atelocollagen Sponge Composite in Critical-Sized Rat Calvarial Defects

“…Although having the same chemical composition, it shares different molecular structure. α-TCP has higher hardness and better bone repair effect 19) , but residues could be remained in bone tissue and because of difficult shaping, clinical application is influenced. This study mixed α-tricalcium phosphate with collagen to form an α-TCP/CS composite material, which has well elasticity and is easy for osteoblast adhesion.…”

Hydroxyapatite and a New Fibrin Sealant Derived from Snake Venom as Scaffold to Treatment of Cranial Defects in Rats

“…Next, an incision was made in the skin to expose the parietal bones. The periosteum was detached with an appropriate surgical instrument and a defect measuring 5 mm in diameter 28 was created in the left parietal bone using a surgical bur in a micromotor (BELTEC LB-100, Araraquara, São Paulo, Brazil). The defect depth was 0.5 mm, avoiding injury to the dura mater in brain ( Figure 1).…”

In vivo Study of the Osteoregenerative Potential of Polymer Membranes Consisting of Chitosan and Carbon Nanotubes

“…Previous researches used defects of 5mm [23][24][25] . The rat skullcap has two parietal bones (right and left) separated by a sagittal suture of medium (middle) location.…”