基因重组人骨形成蛋白2生物学活性及其复合异种骨体内异位植入的成骨活性

Biological activity and osteoinductivity of recombinant human bone morphogenetic protein 2 combined with bone xenograft

目的:观察复合基因重组人骨形成蛋白2异种骨的成骨活性及其量效关系。方法:实验于2001-07/2002-05在安徽医科大学完成。以基因重组人骨形成蛋白-2与去抗原部分脱钙牛松质骨载体复合,制成复合基因重组人骨形成蛋白2的异种骨(基因重组人骨形成蛋白2/脱钙牛松质骨)植入小鼠右股部肌袋内。将6周龄雄性BALB/C小鼠144只,随机分成4组,植入含0.4m g基因重组人骨形成蛋白2/脱钙牛松质骨骨粒组;植入含0.1mg基因重组人骨形成蛋白-2/脱钙牛松质骨骨粒组,单纯植入脱钙牛松质骨载体骨粒组,单纯植入基因重组人骨形成蛋白2组,每组36只。术后7,14,21d取材,通过大体观察、X射线影像学、组织学和骨计量学方法检测各组的诱导成骨活性。结果:144只实验动物在实验过程中无死亡,全部进入结果分析。①单纯植入基因重组人骨形成蛋白2组于光镜下见大量间充质细胞增殖,局部软骨组织生成,软骨细胞成熟。②脱钙牛松质骨与基因重组人骨形成蛋白2复合后,小牛骨松质结合基因重组人骨形成蛋白2呈实体性疏松绒毛结构,骨松质孔洞内填充云絮状基因重组人骨形成蛋白2物质,两者结合良好。③各组术后不同时间组织学检查结果为:植入含0.4mg基因重组人骨形成蛋白2/脱钙牛松质骨骨粒组术后7d出现软骨分化的小鼠有5只,苏木精-伊红染色观察,标本大量间充质细胞被诱导分化为软骨细胞,14d有4只出现新骨诱导的现象,出现多处分散的骨软骨组织,多发生于植骨周围,21d见散在软骨岛和稀疏退变小软骨岛,部分小鼠有新骨形成,但无骨髓及板层骨形成。植入含0.1m g基因重组人骨形成蛋白2/脱钙牛松质骨骨粒组术后7d出现软骨分化的小鼠有3只,见少量间充质细胞被诱导分化为软骨细胞,有零星的间充质细胞分化、过渡为软骨细胞;14d有部分标本可见骨及软骨组织,有的可见稀疏小软骨岛存在,21d有4只出现新骨诱导。单纯植入脱钙牛松质骨载体骨粒组主要表现为纤维结缔组织包绕植骨,植骨周围见组织细胞增生。单纯植入基因重组人骨形成蛋白2组以肌纤维为主,无典型软骨细胞出现。表现为正常横纹肌切面和肌间隔结构。④术后不同时间植入含0.4m g基因重组人骨形成蛋白2/脱钙牛松质骨骨粒组和植入含0.1m g基因重组人骨形成蛋白2/脱钙牛松质骨骨粒组的碱性磷酸酶活性和钙含量均高于对照组,前者高于后者,具有统计学意义(P<0.05)。结论:①基因重组人骨形成蛋白2/脱钙牛松质骨是高效诱导成骨材料,经处理的小牛松质骨是良好的缓释载体,提高了基因重组人骨形成蛋白2的骨诱导能力。②复合基因重组人骨形成蛋白2异种骨的成骨活性与基因重组人骨形成蛋白2的含量成正比。

AIM： To observe the osteoinductivity and the dose-effect of administration of recombinant human bone morphogenetic photein-2（rhBMP-2） combined with antigen-free demineralised bovine cancelous bone （DBCB）. METHODS： The experiment was carried out in Anhui Medical University from July 2001 to May 2002. 144 male BALB/C mice aged 6 weeks were divided into four groups at random （study group A and B, control group A and B）, 36 in each group, rhBMP-2/DBCB 0.4 mg was implanted in the right thigh muscle pouch in the study group A and rhBMP-2/DBCB 0.1 mg in the study group B, DBCB in the control gmup A and rhBMP-2 in the control group B. The mice were sacrificed at days 7, 14, 21 after implantation, lnductivity of rhBMP-2/DBCB was detected by gross observation, X-ray, histological observation and biochemical determination of the samples. RESULTS： All the 144 rats were involved in the result analysis. ①Under light microscope, many mesenchymal cells were found, local cartilage tissues formed and chondrocytes tended to be mature in the control group A. ②rhBMP-2/DBCB presented in a solid loose floss structure, and the hole of spongy bone was filled with flocculent rhBMP-2 materials. ③ Histological examination showed that, in the study group A, chondrogenesis was found in 5 mice on day 7, new bone induction in 4 mice and many dispersed cartilage tissues occurred around the implanted bone on day 14, and scattered cartilage island and sparse degenerative small cartilage island were present on day 21. New bone formed in some mice but no bone marrow and lamellar bone formed. In the study group B, chondrogenesis was found in 3 mice on day 7, in which, a few mesenchymal cells were induced to differentiate into chondrocytes. On day 14, bone, cartilage tissues and sparse bone island were seen in some samples. On day 21, new bone induction occurred in 4 mice. In the control group A, it was common that implanted bone was covered fiber connective tissues, and there were proliferation of histocytes around implanted bone. In the control group B, muscle fibers were mainly present and no typical chondrocytes occurred. Normal striated muscle cut and muscular septal structure were found. ④ The alkaline phosphatase （ALP） activities and calcium contents in the groups A and B were higher than those in the control groups A and B after operation. Meanwhile, the ALP activities and calcium content in the study group A were higher than those in the study group B（P〈0.05）. CONCLUSION：①rhBMP-2/DBCB is a highly ostcoinductive grafting material, and the treated bovine spongy bone is a good slowelivery carrier which can enhance the ostcoinductive capacity of rhBMP-2. ②The osteoinductivity of rhBMP-2/DBCB reconstituted bone xenograft is in direct proportion to the dose of rhBMP-2.