Application of silk fibroin/chitosan/nano-hydroxyapatite composite scaffold in the repair of rabbit radial bone defect.

Silk fibroin (SF), chitosan (CS) and nano-hydroxyapatite (nHA) possess excellent biocompatibility, thus, these were used to construct a SF/CS/nHA composite scaffold. Previously published results identified that this material exhibited satisfactory physical and chemical properties, and therefore qualified as a repair material in bone tissue engineering. The aim of the present study was to investigate the capacity and mechanism of this composite scaffold in repairing bone defects. In total, 45 New Zealand white rabbits were used to model defect in the right radial bone. A radial bone defect was induced, and rabbits were divided into the following treatment groups (n=15 in each): Group A, in which the SF/CS/nHA scaffold was implanted; group B, in which the SF/CS scaffold was implanted; and group C, in which rabbits did not receive subsequent treatment. X-ray scanning, specimen observation and histopathological examination were implemented at 1, 2, 3 and 4 months after modeling, in order to evaluate the osteogenic capacity and mechanism. At 1 month after modeling, the bone density shadow in the X-ray scan was darker in group A as compared with that in group B. Observation of the pathological specimens indicated that normal bone tissues partially replaced the scaffold. At 2 months, the bone density shadow of group A was similar to normal bone tissues, and normal tissue began to replace the scaffold. At 3-4 months after modeling, the X-ray scan and histopathological observation indicated that the normal bone tissues completely replaced the scaffold in group A, with an unobstructed marrow cavity. However, the bone mass of group B was lower in comparison with that of group A. The bone defect induced in group C was filled with fibrous connective tissues. Therefore, it was concluded that the SF/CS/nHA composite scaffold may be a promising material for bone tissue engineering.