Establishment of a rabbit model of parietal critical bone defects:a reference value for identifying parietal critical bone defects / 中国组织工程研究

ABSTRACT

BACKGROUND:Large bone defect caused by various reasons has been a difficult problem in clinical practice. To establish a standard experimental animal model of critical bone defects has vital significance for evaluating the efficacy of bone osteogenesis using various materials and techniques. OBJECTIVE:To establish the rabbit model of parietal critical bone defects and to determine the diameter of the critical defects of parietal bone in limited time. METHODS:10 New Zealand white rabbits were selected. The skul seam was treated as the boundary. Four ful-thickness round defects of bone in the parietal bone were made, with diameters of 4, 5, 6 and 7 mm, so as to establish rabbit models of parietal critical bone defects. Gross anatomical observation, X-ray and cone beam CT were used to determine the bone density in the new bone defect area. The healing of bone defects was evaluated by histological examination. RESULTS AND CONCLUSION:After 12 weeks, the 4 mm group showed high bone healing capacity significantly, and part of the bone bridge had been connected completely. Quantitative analysis of bone mineral density revealed that gray value at defect site and trabecular bone area at the same magnification and the same vision in the 4 mm group were significantly higher than the other three groups (P<0.001). Only a smal amount of new bone in the periphery of bone defects appeared in the 5, 6 and 7 mm groups. The center of defect site was mainly fil ed by fibrous connective tissue. The results confirmed that this study successful y established rabbit models of parietal critical bone defects. During the 12 weeks of observation, bone defects with a diameter of ≥ 5 mm could not be self-healed, which was conformed to the criteria of critical defects of bone, and could be used as a reference value for critical parietal bone defects of a rabbit.