The cellular compatibility and the ectopic bone formation of silk fibroin/hydroxyapatite

Abstract

Objective To observe the cellular compatibility and the ectopic bone formation of silk fibroin/hydroxyapatite(SF/HA-1 and SF/HA-2).Methods The rabbit's bone marrow stromal cells (BMSCs),after being induced to difierentiate into osteoblasts,were transplanted into SF/HA-1 and SF/HA-2,and co-cultured for 3 to 5 days.BMSCs alone were cultured at the same condition to act as controls.The cellular morphology and function(attachment,proliferation and differentiation)were assessed separately by the phase contrast microscopy,HE staining,SEM,MTT assay,and ALP activity.The material leaching liquor was used to test cell toxicity.The difiercntiated osteoblasts were seeded onto SF/HA with a density of 5×107/ml(SF/HA-1+BMSCs as groupl;SF/HA-2+BMSCs as group 2).The compounds with cells were co-cultured for 3 days and implanted into muscular pouch of back of rabbits.and SF/HA alone was implanted as a control group.The effectiveness of bone formation Was assessed by means of gross observation and histology after implantation.Resulls BMSCs could adhere to SF/HA-1 and SF/HA-2,and proliferate and grow on the surface of the composites normally.The cellular activity and function were not affected by the materials,and no statistically significant difference was found among group 1,group 2 and control group(P＞0.05).Cell toxicity test indicated these materials had no toxiC effect on BMSCs.New osteogenesis was detected at the end of the 4th.8th and 12th week after implantation in groups 1 and 2,while there was no new bone formation in control group.Conclusion SF/HA has a good biocompatibility and the tissue engineered bone of SF/HA has a good ability of ectopia osteogenesis in vivo. Key words: Ectopia osteogenesis; Biocompatibility; Scaffold; Tissue engineering