Implantation of tissue-engineered bone with vascular bundles or sensory nerve tracts for large femoral defects:the middle-and long-term expression of calcitonin gene related peptide type Ⅰ receptor

Siyuan CHEN; Le WANG; Shan JIANG; Guoxian PEI

ABSTRACT

BACKGROUND:

Previous study has proved that implantation of the tissue-engineering bone with vascular bundles or sensory nerve tracts can promote bone formation, which may be related to the expression of sensory neuropeptide receptors.

OBJECTIVE:

To investigate the effect of implantation of tissue-engineered bone containing vascular bundles and sensory nerve tracts on the middle-and long-term expression of calcitonin gene-related peptide type Ⅰ receptor (CGRP1R) in the repair of rabbit large femoral defects.

METHODS:

Thirty-six New Zealand white rabbits were enrol ed and modeled into 1.5 cm femoral defects, and then randomized into three groups. Bone marrow mesenchymal stem cells (BMSCs) were subjected to osteoblastic induction for 7 days, and then seeded onto the β-calcium phosphate scaffold to construct the tissue-engineered scaffold.In sensory nerve group, the tissue-engineered scaffold was implanted into the defect region, and autologous sensory nerve bundles were implanted into the lateral groove of the tissue-engineered bone;in vascular bundle group, the tissue-engineered scaffold was implanted, and autologous femoral blood bundles were implanted into the lateral groove of the tissue-engineered bone;in blank control group, only the tissue-engineered scaffold was implanted. X-ray examination, immunohistochemistry and real-time PCR were performed at 24 and 48 weeks postoperatively. RESULTS AND

CONCLUSION:

The X-ray scores in the sensory nerve and vascular bundle groups were significantly higher than that in the control group (P<0.05), but no significant difference was found between sensory nerve and vascular bundle groups. Real-time PCR found that the expression level of CGRP1R mRNA in the vascular bundle group was significantly higher than that in the other two groups (P<0.05), but showed no significant difference between sensory nerve and blank control groups.Immunohistochemistry findings showed that CGRP1R positive expression rate in the sensory nerve and vascular bundle groups was higher than that in the blank control group. These results reveal that implantation of the tissue-engineered bone containing vascular bundles can promote the CGRP1R expression.