骨保护素/骨保护素配体（OPG/OPGL）在骨髓基质干细胞复合同种骨修复骨缺损中的表达及意义

目的 探讨OPG/OPGL蛋白在骨髓基质干细胞（BMSCs）复合同种骨移植修复大鼠桡骨缺损中的表达及意义.方法 4周龄SD大鼠BMSCs体外分离培养,取生长状态良好的第3代细胞复合同种骨.同时取8周龄SD大鼠32只,雌雄不限,制备大鼠双侧桡骨中段5mm节段性骨缺损模型.采用自身对照的方法 ,一侧植入BMSCs及同种异体骨颗粒复合物作为实验组;另一侧植入等量单纯同种异体骨颗粒作为对照组.按术后2、4、8、12周4个时间点（每个时间点8只）处死动物并立即于骨缺损部位取材,大体及组织学观察、免疫组织化学（PV法）检测OPG、OPGL蛋白的表达.免疫组化所得数据经计算机图像分析系统计算其平均光密度值（OD值）.结果 术后各时间点大体形态与组织学观察：实验组骨缺损修复速度均明显优于对照组;OPG蛋白免疫组化结果 显示：2、4、8周实验组OPG的表达高于对照组（P＜0.05）,而12周时两组比较差异无统计学意义（P＞0.05）;OPGL蛋白免疫组化结果 显示：2、4周实验组OPGL的表达高于对照组（P＜0.05）,而8、12周时两组比较差异无统计学意义（P＞0.05）.结论 骨缺损修复区OPG、OPGL蛋白表达水平与骨修复愈合程度密切相关.OPG蛋白表达升高,其成骨作用加强, 而OPGL蛋白表达则相反.提示OPG的高表达可促进骨愈合,减少骨吸收;反之则促进骨吸收.

Expression and significance of OPG/OPGL protein in bone defect repair with bone marrow stromal cells compounded with allogeneic bone in rats

Objective To investigate the expression and significance of OPG/OPGL Protein in bone repair of segmental radial defect in rats with bone marrow stromal cells （BMSCs） compounded with allogeneic bone. Methods The BMSCs were isolated from four-week-old SD rats and were cultured in vitro. The BMSCs in a good state of 3rd generation were selected to compound with allogeneic bone. Meanwhile, segmental radial defect in eight-week-old rats （n=32, female and male） was modeled from a 5mm segment of both middle radial shafts. The rats were divided into two groups by using self-control method, group A as the experimental group implanted with complex of BMSCs and allogeneic bone particles, and group B as the control group merely implanted with an equal amount of allogeneic bone particles as group A. Rats were sacrificed at 4 time points （2, 4, 8, 12 week） with 8 sacrificed per time postoperatively, and their segments with bone defect were taken immediately. Gross and histomorphological observations were carried out and immunohistochemical PV analysis was performed at each of the 4 time points respectively to detect the expression of OPG/OPGL protein. According to the data obtained from the immunohistochemical PV analysis, the average optical density （OD） value was calculated by computer system of image analysis. Results Of the gross and histomorphological observation results at each time point, group A showed significantly shorter recovery period than group B at all the time points. Of the immunohistochemical PV analysis results, OPG protein expression in group A was significantly higher than group B at 2, 4, 8 week （P〈0.05） and no significant difference was found between two groups at 12 week （P〉0.05）; OPGL protein expression in group A was significantly higher than group B at 2, 4 week （P〈0.05） and no significant difference between two groups at 8, 12 week （P〉0.05）. Conclusions The expression level of OPG/OPGL protein in the zone of bone defect repair is closely correlated with the degree of bone repair and healing. The increase of OPG protein expression enhances the osteogenesis, while the situation is opposite with respect to OPGL protein expression. It can be indicated that high-level expression of OPG protein may promote bone healing and reduce bone absorption, and vice versa.