Construction of rabbit anatomical three-dimensional models of large segmental tibial defects / 中国组织工程研究

ABSTRACT

BACKGROUND:Tissue-engineered bone has been considered to be a promising candidate for the repair and reconstruction of load-bearing large segmental bone defects. Currently, the studies on the application of tissue-engineered bone mainly focus on cel-scaffold or cytokine-scaffold constructs, which haveshed light upon the repair of large segmental bone defects. OBJECTIVE:Toestablish simple and convenient tissue engineering of anatomicaly shaped tibial bone defect models using three-dimensional rapid prototyping technology to manufacture rabbit tibia biomimetic artificial bone scaffolds. METHODS:Three-dimensional electronic models were constructed using Mimic software. Hydroxyapatite/polycaprolactonescaffolds were manufactured by fused deposition modeling equipment. Fifty rabbits aged 6 months were randomly divided into three groups blank control(n=3), control(n=6) and experimental groups(n=6), respectively. Tibial defects ranged 1.2 cmweremade in al groups. No treatment was given in blank control group. The bone defects in control and experimental groups were repaired with autogenous osteotomized bone and anatomicaltissue-engineered bone, respectively, and fixed with plates and screws. RESULTS AND CONCLUSION:(1) Rabbit tibial bone measurementstibiallengthwas (93.77±0.59)mm, tibiofibular transverse diameter(8.36±0.13)mm, sagittal diameter(5.97±0.12)mm, average thickness of bone cortex(1.20±0.10)mm, average diameter of the medulary cavity(4.30±0.06)mm. Anglebetween the connection line of the midpoints of superior and inferior articular surfaces at the side of tibial bone models and the connection lineof the midpoints of superior and inferior intersecting surfaces at the side of osteotomized bone modelswasα=(5.97±0.13)°.(2) X-ray in bone defects at postoperative 4 and 12 weeks, no obvious displacement and angulated deformity were found in bone grafts, suggesting the good bone defect repair.(3) Histological examination at postoperative 4 weeks, bone scaffolds were filed with new bone in the experimental group. Furthermore, considerably increased new bone formation and mineralization were observed at postoperative 12 weeks.(4) General observation no obvious displacement and angulated deformity occurredin bone defect grafts at postoperative 4 and 12 weeks. These findings suggest that rabbit anatomical models of large segmental tibial bone defects with good stability were constructed using three-dimensional prototyping technology, which may simulate the structure and function of bone tissue and be used for guiding the new bone regeneration.