可塑形组织工程骨修复兔颅骨缺损的组织学及力学研究

目的探讨用藻酸钙凝胶、成骨细胞和骨粉复合构建可塑形组织工程骨修复兔颅骨缺损后,体内成骨的组织学及生物力学特征。方法28只日本大耳白兔,随机分为A组(16只)、B组(8只)和C组(4只)。制备兔颅骨左右两侧直径1cm的骨膜-颅骨全层缺损,左侧用藻酸钙凝胶-成骨细胞-骨粉填补修复为A1组(n=16);右侧用藻酸钙凝胶-骨粉填补修复为A2组(n=16);B组骨缺损不作处理,为空白对照组(n=16);C组为正常组。术后6周和12周时,行大体观察及组织学观察;12周时行生物力学测试。结果术后6、12周时,A1组:颅骨缺损基本被硬组织所修复,镜下见材料已大部分被骨组织替代,成骨面积为40.92%±19.36%;A2组:材料部分被骨组织替代,成骨面积为18.51%±6.01%;B组:颅骨缺损边缘可见硬组织形成,镜下见修复组织以致密纤维组织为主,成骨面积为12.72%±9.46%。术后12周,生物力学测试修复组织能耐受的最大压力载荷,A1组37.33±2.95N;A2组30.59±4.65N;B组29.5±2.05N;C组41.55±2.52N;A1组明显大于A2组和B组(P<0.05)。最大载荷时应变位移,A1组1.05±0.20mm;A2组1.35±0.44mm;B组1.57±0.31mm;C组0.95±0.17mm;A1组小于B组(P<0.05)。载荷/应变比值,A1组35.82±6.48N/mm;A2组24.95±12.40N/mm;B组19.90±5.47N/mm;C组47.57±11.22N/mm;A1组大于B组(P<

MORPHOLOGICAL AND BIOMECHANICAL STUDY ON IN VIVO OSTEOGENESIS AFTER REPAIR OF CRANIAL DEFECTS WITH PLASTIC ENGINEERED BONE IN RABBITS

OBJECTIVE: To investigate the morphology and biomechanics of in vivo osteogensis after repairing rabbit skull defects with plastic engineered bone which was prefabricated with alginate gel, osteoblasts and bone granules. METHODS: Twenty-eight rabbits were divided into group A (n=16), group B (n=8) and group C (n=4). The bilateral skull defects of 1 cm in diameter were made. Left skull defects filled with alginate gel-osteoblasts-bone granules (group A1) and right skull defects filled with alginate gel-bone granules (group A2). The defects of group B was left, as blank control and group C had no defect as normal control. The morphological change and bone formation were observed by methods of gross, histology and biomechanics. RESULTS: In group A1, the skull defects were almost entirely repaired by hard tissue 12 weeks after operation. The alginate gel-osteoblasts-bone granule material had changed into bone tissue with few bone granules and some residuary alginate gel. The percentage of bone formation area was 40.92% +/- 19.36%. The maximum compression loading on repairing tissue of defects was 37.33 +/- 2.95 N/mm; the maximum strain was 1.05 +/- 0.20 mm; and loading/strain ratio was 35.82 +/- 6.48 N/mm. In group A2, the alginate and bone granules material partially changed into bone tissue 12 weeks after operation. The percentage of bone formation area was 18.51% +/- 6.01%. The maximum compression loading was 30.59 +/- 4.65 N; the maximum strain was 1.35 +/- 0.44 mm; and the loading/strain ratio was 24.95 +/- 12.40 N/mm. In group B, the skull defects were mainly repaired by membrane-like soft tissue with only few bone in marginal area; the percentage of bone formation area was 12.72% +/- 9.46%. The maximum compression loading was 29.5 +/- 2.05 N; the maximum strain was 1.57 +/- 0.31 mm; and the loading/strain ratio was 19.90 +/- 5.47 N/mm. In group C, the maximum compression loading was 41.55 +/- 2.52 N; the maximum strain was 0.95 +/- 0.17 mm; and the loading/strain ratio was 47.57 +/- 11.22 N/mm. CONCLUSION: The plastic engineered bone prefabricated with alginate gel-osteoblasts-bone granule may shape according to the bone defects and has good ability to form bone tissue, whose maximum compression loading can reach 89% of normal skull and the hardness at 12 weeks after operation is similar to that of normal skull.