可塑形组织工程骨修复兔颅骨缺损的组织学及力学研究

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

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;

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; themaximumstrainwas1.57±0.31mm;andthe 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.