载rhBMP-2人工骨促进家兔脊柱融合实验研究

BONE INDUCTIVE EFFECTS OF rhBMP-2 LOADED POROUS CPC IMPLANTS ON SPINE FUSION IN RABBITS

目的探讨CPC作为rhBMP-2载体促进家兔脊柱融合的作用及效果。方法取1 mg rhBMP-2分别与1 g CPC、体积为6.0 cm×2.0 cm×0.5 cm的医用明胶海绵(absorbable gelatin sponge,AGS)吸附复合,冻干制备rhBMP-2/CPC、rhBMP-2/AGS生物材料。45只24周龄新西兰兔,体重2.5～3.5 kg,随机分为A(n=17)、B(n=11)、C(n=17)3组。暴露L5、6横突,将L5、6横突后缘骨皮质磨除,露出松质骨,行后路双侧L5、6横突间植骨,A、B、C组分别植入rhBMP-2/CPC、rhBMP-2/AGS、CPC 3种材料。于术后4、8、24周,行大体、组织学观察及影像学检查。结果术后4、8周脱钙组织切片,A组均见明显骨痂连接;B组仅见小片骨痂;C组见纤维连接,局部少许软骨。术后4周A、B、C组脱钙组织切片评分分别为(7.30±0.76)、(3.68±1.60)和(1.75±0.54)分,术后8周分别为(8.32±1.11)、(3.75±1.23)和(1.47±0.23)分;各时间点A、B组以及A、C组比较,差异均有统计学意义(P<0.05)。不脱钙硬组织切片术后4、8周A组均见类松质骨样骨组织再生,C组植入物周围见纤维连接,少许成骨。术后4周单位面积内成骨面积A、C组间比较差异无统计学意义(P>0.05);术后8周,A、C组间比较差异有统计学意义(P<0.05)。三维重建CT评分A、B、C组分别为(2.50±0.57)、(1.00±0.00)和(1.00±0.00)分,C组与A、B组以及A、B组间比较差异均有统计学意义(P<0.05)。结论CPC作为rhBMP-2载体能够促进家兔脊柱骨性融合,可作为一种新型的人工骨修复材料。

Objective To investigate the effect of rhBMP-2 combined with porous CPC on spine fusion in rabbits. Methods rhBMP-2 （1 mg） was loaded with 1 g CPC and 6.0 cm× 2.0 cm× 0.5 cm absorbable gelatin sponge （AGS）, respectively, and thereafter frozen to prepare the biomaterial of rhBMP-2/CPC and rhBMP-2/AGS. Forty-five 24-week-old New Zealand rabbits （weight 2.5-3.5 kg） were randomly divided into 3 groups： group A （n=l 7）, group B （n=11） and group C （n= 17）. With the exposure and removal of L5, 6 transverse process＇s posterior bone cortex in all the rabbits, the corresponding cancellous bones were exposed and the posterior bilateral intertransverse bone grafting of L5, 6 were performed on the three groups, then the rhBMP-2/CPC, rhBMP-2/AGS and CPC was implanted into the rabbits of group A, B and C, respectively. Gross observation, histology assay and image examination were conducted 4, 8 and 24 weeks after operation. Results Decalcified hard tissue section demonstrated obvious callus connections in group A, small pieces of callus in group B, and fibrous connection and few cartilage in group C at 4 and 8 weeks after operation. By Kacena measurement standard, the score of group A, B and C at 4 weeks after operation was （7.30 ± 0.76）, （3.68 ± 1.60） and （1.75 ± 0.54） points, respectively, and their score at 8 weeks after operation were （8.32 ± 1.11）, （3.75 ± 1.23） and （1.47 ± 0.23） points, respectively, indicating there were significant differences between group A and group B as well as between group A and group C at different time points （P 〈 0.05）. Undecalcified hard tissue section demonstrated that there was cancellous bone-like tissue regeneration in group A, and fiber connection around the implants and little ossification in group C at 4 and 8 weeks after operation. By three dimensions reconstructed CT, group A, B and C scored （2.50 ± 0.57）, （1.00 ± 0.00） and （1.00 ± 0.00） points respectively, indicating there was a significant difference between group C and groups A and B as well as between group A and group B （P 〈 0.05）. Conclusion As a carrier of rhBMP-2, the CPC is capable of promoting spine bone fusion in rabbits and is a new type of artificial bone repair material.