OBJECTIVETo evaluate the different effect on the expression of Calcitonin gene related peptide (CGRP)and neuropeptide Y (NPY) between tissue engineered bone with vascular bundle graft in vivo and that with sensory nerve tract graft in vivo.

METHODThirty-six healthy New Zealand rabbits were divided into 3 groups randomly and equally: vascular bundle group (A), sensory nerve tract group (B), tissue-engineering group (C). Group A segmental bone defect of 1.5 cm long was made at the right femur in each animal. After plate fixation, the defects were implanted respectively with the engineered bone prepared in the above-mentioned 3 methods. At 3, 6 and 12 months post-operatively, the distribution of CGRP and NPY in the new bone were detected by immunohistochemistry and analyzed semi-quantitatively by image analysis software.

RESULTSCGRP and NPY immuno-histochemical results indicated their contents increased significantly in all 3 groups as time passed (P = 0.000). Compared with group B, the contents of CGRP and NPY in group A significantly increased at 3 months (P = 0.000), but there was no statistic difference between them at 6 or 12 months (P > 0.05). The expression of CGRP and NPY in both group A and B were significantly more than that in group C at 3, 6 or 12 months (P = 0.000).

CONCLUSIONImplantation of vascular bundle into tissue-engineered bone can significantly improve the CGRP and NPY contents at early 3 months comparing with Implantation of sensory tract into tissue-engineered bone, but the changes are not significant at 6 or 12 months post-operatively.