3D Printed Hydroxyapatite/Silk Fibroin/Polycaprolactone Artificial Bone Scaffold and Bone Tissue Engineering Materials Constructed with Double-Transfected Bone Morphogenetic Protein-2 and Vascular Endothelial Growth Factor Mesenchymal Stem Cells to Repair Rabbit Radial Bone Defects

Abstract

To examine the effect of bone tissue engineering material constructed via 3D printed nanohydroxyapatite/silk fibroin/polycaprolactone (nHA/SF/PCL) artificial bone scaffolds and doubletransfected BMP-2/VEGF mesenchymal stem cells in repairing rabbit radial bone defects, 60 New Zealand rabbits were randomly selected, and with the establishment of a 15 mm bone defect model upon the middle of the anterior right radius bone. The rabbits were randomly divided into 4 groups, with each group composed of 15 rabbits: Group A (nHA/SF/PCL BMP-2/VEGF), Group B (simple nHA/SF/PCL), Group C (simple BMP-2/VEGF), Group D (blank control). Our team recorded the eating, movement, redness, exudation, and so forth across each sample group following the operation. The bone protein expression levels were measured via western blotting following 12 weeks post-operation. Histological observation was carried performed via tissue sections. Following the operation procedure, the wound healed healthily across the 4 experimental groups, no serious infections occurred, only a few rabbits exhibited redness, exudation, pus, and other phenomena, and there was no significant difference present in each group (P > 0.05). The A group took the shortest time to recover its autonomous activity ability, followed by the B group, and the D group took the longest time to recover its autonomous activity ability. From western blotting tests, the A group possessed the highest BMP-2 and OCN expression levels, and have significant difference existed with the B, C, and D group (P < 0.05). The order of expression level of BMP-2 and OCN across the other three groups were group C > group B > group D, respectively. The results of a histological section performed at 12 weeks post-operation revealed that there was no immune response present and no adverse inflammatory reaction occurring within each experimental group. Among the rabbits, the A group exhibited an apparent plate layer new bone formation, bone trabeculae were arranged regularly, and there was no obvious space within the new bone tissue; furthermore, the repair of the bone defect was completed. The B group still exhibited some bone scaffold remaining within the implantation area, and there was a small gap between the new bone tissue, and several bone defects had not been repaired. The C group of bone defects presented only a small number of new bone formation, and bone defect repair effect was not obvious. The D group still possessed large bone defects and exhibited poor repair of bone defects. The nHA/SF/PCL composite of artificial bone scaffold and double-transfected BMP-2/VEGF mesenchymal stem cells was effective in repairing radial bone defects within rabbits, and was superior to using nHA/SF/PCL bone scaffolds alone.