Mesenchymal stem cells modified with Runt-related transcription factor 2 promote bone regeneration in rabbit mandibular distraction osteogenesis

Abstract

This work investigated mesenchymal stem cells (MSCs) modified with Runt-related transcription factor 2 (Runx2) therapy for bone regeneration in rabbit mandibular distraction osteogenesis. Forty-eight New Zealand mature white rabbits were randomly divided into three groups after the rabbit model of mandibular distraction osteogenesis was established: reconstruction plasmid modified with Runx2 (group A), plasmid without Runx2 (group B), and the same dose of saline as control (group C). At the fifth day of distraction phase, MSCs with reconstruction plasmid modified with adv-hRunx2-gfp were injected into the distraction gap of group A. MSCs with reconstruction plasmid modified with adv-gfp was injected into the distraction gap of group B, whereas group C was injected with the same dose of saline. At 8 weeks after injection, all animals were sacrificed, and the distracted mandibles were harvested. The general imaging histological observation and three-point bending test were used for evaluation. CT plain scan and histological analysis confirmed that the amount of new bone forming in the distraction gap of group A was significantly higher than those in groups B and C. Dual-energy X ray and three-point bending test results also showed that the bone mineral density, bone mineral content, and maximum load of the distraction gap of group A were significantly higher than those of groups B and C (P<0.01). Runx2-ex vivo gene therapy based on MSCs can effectively promote the bone regeneration in rabbit mandibular distraction osteogenesis and shorten the stationary phase. Therefore, reconstruction of craniofacial fracture would be a valuable strategy