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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.
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Objective To compare patellar ring,Kirschner wire tension band and patellar ring plus Kirschner wire in fixation for treatment of patella fractures.Methods A retrospective analysis was conducted on the 285 patients with patellar fracture who had been treated between September 2009 and January 2016.They were 155 men and 130 women,with an average age of 45.5 years (from 18 to 70 years).Their fractures included 176 transverse,28 longitudinal split and 81 comminuted ones.They were divided into 3 groups according to their different internal fixation methods:patellar ring fixation (98 cases),Kirschner wire tension band (92 cases),patellar ring plus Kirschner wire fixation (95 cases).The 3 groups were compared in terms of operative time,intraoperative bleeding,fracture healing time,knee function by B(o)stman score at the last follow-up and postoperative complications.Results The operative time in the patellar ring group(58.9 ±6.4 min) was significantly shorter than in the Kirschner wire group (71.8 ± 7.8 min) and in the patellar ring plus Kirschner wire group (74.4 ± 8.0 min) (P ＜ 0.05).There were no statistical significant differences between the 3 groups in fracture healing time and intraoperative bleeding (P ＞ 0.05).The good to excellent rate of knee function at the last follow-up in the Kirschner wire tension band group was 100.0％ (92/92),significantly higher than in the patellar ring group (90.8％,89/98) and in the patellar ring plus Kirschner wire group (91.6％,87/95) (P ＜ 0.017).There was no significant difference in postoperative complication rate between the patellar ring fixation group (2.0％,2/98),Kirschner wire tension band fixation group (1.1％,1/92) and the patellar ring plus Kirschner wire group (2.1％,2/95) (P ＞ 0.05).Conclusion Internal fixation with Kirschner wire tension band has definite curative effect on patellar fractures,showing the advantages of less operative invasion,fewer postoperative complications,better functional recovery of the affected knee joint,and lower price over the other 2 internal fixation methods.
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Objective To investigate whether tissue engineered bone with implanted vascular bun-dles can up-regulate release of vascular endothelial growth factor (VEGF) in models of femoral defect in rabbits.Methods Thirty-two rabbits were randomized into 2 even groups.In both groups, a segmental bone defect of 15 mm in length was made at the left femur before a tissue engineered bone was inserted into the defect.In the experimental group, a femoral vascular bundle was implanted into the tissue engineered bone.In the control group, there was no vascular implantation.At 2, 4, 8, and 12 weeks after implantation, samples were taken to determine new bone formation by histology and expression level of VEGF by immuno-histochemistry.Results The new bone formation was significantly higher in the experimental group at the end of 4, 8, and 12 weeks(P < 0.05) .The expression level of VEGF in the experimental group was also significantly higher than in the control group at all time points after operation, and the expression of VEGF peaked at 4 weeks.Conclusion Tissue engineered bone with vascular bundle implanted can up-regulate VEGF release in models of femoral defect in rabbits.
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Objective To explore whether the respective implantation of vascular bundles and sensory nerve tracts into a tissue-engineered bone will affect the expression of CGRP (Calcitonin gene related peptide) and its receptor. Methods Fifty-four New Zealand rabbits were randomly divided into 3 even groups for implantation of sensory nerve tracts (group A),implantation of vascular bundles (group B),and a control group of simple tissue-engineered bone (group C) . Animals were sacrificed 4,8,12 weeks after implantation,respectively. Masson staining was conducted to observe the process of bone formation and re-molding. CGRP and CGRPR-1 expressions in the new bone were measured by immunohistochemistry and Real-time PCR at 4,8 and 12 weeks after implantation. Results At all time points,the CGRP and CGRPR-1 expressions in groups A and B were significantly higher than in group C (P<0.05),and those in group A were higher than in group B too (P<0.05) . Over time,the expressions of CGRP and CGRPR-1 mRNA in each group in the new bone tissue were gradually reduced after an initial increase. The neuropeptide expression at the 8th week was higher than those at the 4th and 12th weeks. The neuropeptide expression at the 4th week was the lowest. The expression of CGRP was mainly localized in the periphery of newly generated bone,periosteum and the blood vessels. The expression of CGRPR-1 was mainly localized in the periphery of osteoblasts. Conclusions Implantation of either vascular bundles or sensory nerve tracts can promote neuropeptide secretion. The vascular bundle implantation may result in higher expressions of CGRP and CGRPR-1 than sensory nerve tract implantation.