MicroCT Evaluation of Three-Dimensional Mineralization in Response to BMP-2 DosesIn Vitroand in Critical Sized Rat Calvarial Defects

Abstract

Numerous growth factors, peptides, and small molecules are being developed for bone tissue engineering. The optimal dosing, stability, and bioactivity of these biological molecules are likely influenced by the carrier biomaterial. Efficient evaluation of various formulations will require objective evaluation of in vitro culture systems and in vivo regeneration models. The objective of this paper is to examine the utility of microcomputed tomography (microCT) over conventional techniques in the evaluation of the bone morphogenetic protein-2 (BMP-2) dose response effect in a three-dimensional (3D) in vitro culture system and in an established calvarial defect model. Cultured MC3T3-E1 osteoblasts displayed increased cellular density, extracellular matrix (ECM) production, and mineralization on 3D poly(lactic-co-glycolic acid) (PLGA) scaffolds in a BMP-2 dose dependent manner. MicroCT revealed differences in shape and spatial organization of mineralized areas, which would not have been possible through conventional alizarin red staining alone. Additionally, BMP-2 (doses of 30 to 240 ng/mm(3)) was grafted into 5 mm critical sized rat calvarial defects, where increased bone regeneration was observed in a dose dependent manner, with higher doses of BMP-2 inducing greater bone area, volume, and density. The data revealed the utility of microCT analysis as a beneficial addition to existing techniques for objective evaluation of bone tissue engineering and regeneration.

Correlation of Computed Tomography with Histology in the Assessment of Periprosthetic Defect Healing

“…The micro-CT findings were consistent with those of Cowan et al, who found micro-CT was highly accurate in assessing the quality and quantity of defect healing with bone protein in a rat calvarial model [8]. In their study, micro-CT delineated some ultrastructural details of graft incorporation not possible with the histologic technique used, yet a considerable benefit was that the resolution of their micro-CT data was not adversely affected by any artifacts as a result of the presence of metal.…”

BMP2/7 heterodimer is a stronger inducer of bone regeneration in peri-implant bone defects model than BMP2 or BMP7 homodimer

“…The recommended dose of BMP2 in the manufacturer's instruction is about 400 ng/mm 3 . It was reported that BMP2 could induce bone regeneration in CSD of rat calvaria at the dose of 30 to 240 ng/mm 3,30) . In our previous study, we found that the effective concentration of BMP2/7 to induce osteoblastogenesis was significantly lower than those of BMP2 and BMP7 homodimers 9) .…”

Osteogenic Evaluation of DNA/Protamine Complex Paste in Rat Cranial Defects

“…Bone formation in the calvarial defect model occurs under unloaded conditions. Cowan et al 22) described that recent advances in imaging techniques have been used to assess and characterize fine bony structures such as trabecular bone architecture in vitro and in vivo and that -CT data can accurately substitute for conventional histological sections for bone structure evaluations. Thus, in the present study, CT image analysis was used for new bone formation evaluations.…”