Effect of bone marrow mesenchymal stem cells combined with Shh modified nano-hydroxyapatite/collagen for femoral defect repair / 中国组织工程研究

ABSTRACT

BACKGROUND: SSh as a Hedgehog signal protein can promote bone development, growth and remodeling.OBJECTIVE: To investigate the effect of bone marrow mesenchymal stem cells (BMSCs) combined with Shh modified nano-hydroxyapatite/collagen (nHAC) in the repair of femoral defects in rats.METHODS: Forty-eight Sprague-Dawley rats were randomly divided into four groups, and the model of femoral defects was established in these rats. At 14 days after modeling, experimental group was implanted with the BMSCs/Shh modified nHAC, scaffold group was implanted with simple nHAC, cell scaffold group was implanted with BMSCs/nHAC,and blank control group was without any implantation. At 3, 6, 9, 12 weeks after repair, X-ray examination, bone density measurement and bone biopsy in bone defect area were performed.RESULTS AND CONCLUSION: (1) X-ray examination The Lane-Sandhu X-ray score and bone mineral density value in the experimental group at different time points after operation were significantly higher than those in the other three groups (P < 0.05). (2) Hematoxylin-eosin staining 12 weeks after repair, a small amount of bone tissues but no bone marrow formed in the scaffold group; a small amount of bone tissues with absence of bone marrow formed in the cell scaffold group, and the residual scaffold was visible; in the experimental group, the scaffold was completely absorbed,and mature bone and medullary cavity formed with presence of bone marrow. (3) Scanning electron microscope observation 12 weeks after repair, irregular arrangement of bone fibers and a large number of bone fossae were observed in the scaffold group; the cell scaffold group showed a large number of osteoblasts, but bone fibers still arranged irregularly; in the presence of the Haversian system, a large number of regularly arranged bone trabeculae were detective in the experimental group. These results elucidate that the Shh modified nHAC/BMSCs complex can promote the repair of bone defects.