Tissue-engineered bone with vascular bundles or sensory nerve tracts for repairing large bone defects / 中国组织工程研究

ABSTRACT

BACKGROUND: Neuropeptides, a kind of endogenous active substance in nerve tissues, can modulate physiological functions of multiple body systems.OBJECTIVE: To observe the effects of vascular bundles or sensory nerve tracts implanted into tissue-engineered bone for rabbit large bone defects on the expression levels of calcitonin gene-related peptide (CGRP) and neuropeptide-Y.METHODS: Fifty-four New Zealand rabbits were enrolled to make model of large bone defects, and then, the animal models were randomly divided into three groups, including sensory nerve tract, vascular bundle, and control groups (n=18 per group), followed by implanted with sensory nerve tracts, vascular bundle, and tissue-engineered bone without sensory tracts or vascular bundle, respectively. The defected bone received gross and Masson staining at 4, 8 and 12 weeks after modeling, to compare the expression levels of CGRP and neuropeptide-Y in each group.RESULTS AND CONCLUSION: mRNA expression levels of CGRP and neuropeptide-Y in the sensory nerve tract and vascular bundle groups were significantly higher than those in the control group at different time points after modeling (P < 0.05). mRNA expression levels of CGRP and neuropeptide-Y in the tissue-engineered bone began to be increased and peaked at the 8th week, and then decreased (P < 0.05), which were the lowest at the 4th week (P < 0.05).Immunohistochemical staining results showed that CGRP was mainly found in the bridge, periosteum of newly born bones and around blood vessels; while neuropeptide-Y mainly localized in the medullary cavity and around blood vessels. These results indicate that the implantation of vascular bundle and sensory nerve tracts for bone defects can upregulate the expression levels of CGRP and neuropeptide-Y, and promote bone repair. However, sensory tract implantation may cause sensory impairment; thereafter, vascular bundle implantation is more suitable for ideal tissue-engineered construction to meet physical requirements.