Osteostimulating Ability of beta-tricalcium Phosphate/collagen Composite as a Practical Bone-grafting Substitute: In vitro and in vivo Comparison Study with Commercial One

Abstract

A biocompatible and biodegradable bioceramic, beta-tricalcium phosphate (beta-TCP) has been widely considered as a safe and effective alternative to autograft for bone reconstruction due to its excellent osteoconductivity. Here, we prepared the composite of beta-TCP and collagen (beta-TCP/col) to investigate whether such a bone extracellular matrix (ECM)-mimetic synthetic bone graft can achieve a highly accelerated bone growth comparable to a commercially available bone substitute. The bone regenerating effects of the beta-TCP/col block were evaluated in vitro and in vivo by comparison with Bio-Oss Collagen (R) (Bio-Oss/col). Preosteoblasts showed similar levels of cell adhesion and proliferation in the beta-TCP/col and Bio-Oss/col scaffolds. Expression levels of osteogenic differentiation marker genes, including alkaline phosphatase (ALP), bone sialoprotein (BSP) and osteocalcin (OCN), increased significantly in cells on the collagen plug compared to the control (without any bone graft material). Notably, cells on the beta-TCP/col scaffold exhibited more than 2-fold higher expression levels of ALP and OCN compared to the Bio-Oss/col scaffold. In addition, in vivo animal experiments showed that the beta-TCP/col scaffold induced a remarkably accelerated bone formation (similar to 69.54%) compared to the Bio-Oss/col scaffold (similar to 67.08%) and the collagen plug (similar to 11.47%) at 8 weeks after implantation. These results indicated that the composite of beta-TCP and collagen (beta-TCP/col) showing a comparable bone-regenerating ability could be used as a substitute for the most commercially available Bio-Oss Collagen (R).