Effect of local gene therapy on expression of Wnt3a and β-catenin in callus of distraction gap during mandibular distraction osteogenesis in rabbits / 中华医学美学美容杂志

ABSTRACT

Objective:To investigate the effect of electroporation-mediated local gene therapy on the expression of Wnt3a and β-catenin in callus of distraction gap during mandibular distraction osteogenesis of rabbits.Methods:The experiments were conducted in the laboratory of the Affiliated Friendship Plastic Surgery Hospital of Nanjing Medical University from September 2019 to December 2019. Forty eight New-Zealand rabbits were randomly divided into control group (group A), gene therapy group (group B) and normal saline group (group C), with 16 rabbits in each group. After bilateral mandible osteotomy and distractors were implanted, the distractors were activated at a speed of 0.8 mm/d on 4th day, postoperatively, and lasted for 7 days, followed by consolidation period. Group A distracted only, group B was subject to local injection of recombinant plasmid pIRES-hBMP2-hVEGF165 in the distraction gap and electroporation stimulation at the beginning of activation distractors; and group C local injection of the same dose of normal saline in the distraction gap and electroporation stimulation at the beginning of activation distractors. Four animals in each group were sacrificed on the day at the end of distraction, 7th, 14th, 28th days of consolidation period, respectively. The callus in the distraction gap was taken for immunohistochemical staining and RT-PCR to detect the expression of Wnt3a and β-catenin, and image analysis was performed. SPSS 22.0 statistical software was used for data analysis.Results:Immunohistochemical staining showed that Wnt3a and β-catenin were mainly located in the cytoplasm and nuclei of fibroblasts, chondrocytes and osteoblasts in callus tissue. Immunohistochemistry and RT-PCR showed that the expression of Wnt3a and β-catenin reached a peak at the end of distraction. With the disappearance of distraction tension, the expression of Wnt3a and β-catenin gradually decreased. After gene therapy intervention, the expression of Wnt3a and β-catenin was significantly increased, and the expression of Wnt3a and β-catenin in group B was the highest at each time point, with statistically significant difference compared with groups A and C ( F=96.3, P<0.01). Conclusions:Gene therapy promotes the expression of Wnt3a and β-catenin in the callus of distraction gap, regulating the balance of the bone reconstruction system and thus promoting the formation of new bone in the distraction gap.