Silk fibroin/nano-hydroxyapatite composite material as a lumbar interbody implant: a study on initial segmental stability / 中国组织工程研究

ABSTRACT

BACKGROUND: With the development of nanotechnology, silk fibroin/nano-hydroxyapatite composite materials used for tissue repair have been reported; however, there are few reports on its use in spinal stability.OBJECTIVE: To explore the feasibility of silk fibroin/nano-hydroxyapatite composite materials for the initial segmental stability of the reconstructed spine.METHODS: Thirty-six New Zealand rabbits were randomly divided into three groups, and the L4/5 nucleus pulposus was removed in all the animals. Autologous bone group was implanted with autologous bone, experimental group implanted intervertebrally with silk fibroin/nano-hydroxyapatite composite material, and control group implanted with hydroxyapatite.At 12 weeks after implantation, lumbar interbody fusion was observed using X-ray, the spinal stability of the fusion segments was measured by biomechanical test, and histologically, bone graft fusion and material degradation at the surgical site were observed.RESULTS AND CONCLUSION: (1) X-ray observation In the autologous bone group, the experimental group and the control group, there were respectively 11, 7, 2 rabbits meeting the standard of fusion. (2) Biomechanical test The spinal activity during flexion-extension was significantly lower in the experimental group than the autogenous bone group and control group (P < 0.05). (3) Histological observation Bony union was found at the junction between the iliac bone and surrounding tissues in the autologous bone group, and a large number of bone cells and fibroblasts were found around the new bone, while woven bone was found inside. The material was partially degraded in the experimental group,fibrous tissues were visible in the surrounding tissue, new woven bone was found inside, and pit cells and bone cells were scattered. Blood vessel growth around the material was visible in the control group, and a large number of macrophages were found inside the material. To conclude, the silk fibroin/nano-hydroxyapatite composite material has good biocompatibility and mechanical properties, which could rebuild the initial segmental stability in the rabbit spine in the short time.