生物衍生骨与骨髓间充质干细胞复合修复兔桡骨大段缺损

背景：生物衍生支架材料具备与自身骨相似的结构和微环境，具有较好的应用前景。 目的：探讨生物衍生骨复合成骨诱导的骨髓间充质干细胞修复兔桡骨的节段性骨缺损的可行性，并与单纯生物衍生骨进行比较。 设计、时间及地点：随机对照动物实验，于2007-01/2008-01在南华大学生命科学院实验室完成。 材料：同种异体骨经脱脂、脱蛋白、部分脱钙和冻干等方法处理后制备生物衍生骨支架材料，与自体骨髓间充质干细胞复合制备组织工程骨支架材料。 方法：25只健康成年新西兰大白兔双侧桡骨制备中段15 mm的骨缺损，随机取其中20只兔右侧桡骨为实验组植入组织工程骨，左侧为对照组植入单纯生物衍生骨，不做内外固定；另5只兔双侧骨缺损处不植入任何材料作为空白组。 主要观察指标：应用X射线放射学检查及组织学观察比较3组骨缺损修复的能力。 结果：X射线显示随时间延长骨折处骨痂逐渐增多, 实验组8周基本愈合，12周塑形完成；对照组骨痂少，愈合时间推迟；空白组术后12周骨缺损未见骨性修复，最后形成骨不连。术后2，4，8，12周实验组放射学检查评价新骨生成优于对照组 (P < 0.05)。组织学检查显示实验组术后4周时材料开始吸收，8周基本降解吸收被新生骨取代，12周完全修复；对照组明显推迟，新骨生成速度、生成量低于实验组(P < 0.05)；空白组各时点均无新骨形成，最后缺损由纤维组织充填。 结论：成骨诱导的间充质干细胞／生物衍生骨复合构建组织工程化骨植入修复兔桡骨缺损能够加速新骨形成，其修复能力明显优于单纯生物衍生骨。

Bio-derived bone compound with marrow stromal stem cells to repair large segmental radial bone defects in rabbits

BACKGROUND: The bio-derived scaffold materials have the similar structure and microenvironment with the autologous bone, thus they are promising to apply. OBJECTIVE: To observe the feasibility of repairing large segment radial defects with bio-derived bone combined with bone marrow stromal stem cells, and to compare the curative effects with bio-derived bone alone. DESIGN, TIME AND SETTING: Randomization design animal controlled trials were performed at the laboratory of Life Science College of Nanhua University from January 2007 to January 2008. MATERIALS: Bio-derived bone scaffold was prepared through a serial of physical and chemical processes, including degreasing, deproteinization, partial decalcification and freeze drying. Bio-derived bone scaffold was then co-cultured with induced bone marrow stromal stem cells to construct tissue engineering bone scaffold. METHODS: Twenty-five healthy, adult, New Zealand rabbits were used in this study to establish a 15-mm length of radius-periosteum defects on both sides of radial bone. Tissue engineering bones were implanted into the segmental bone defects of 20 rabbits in right radius, taken as the experimental group; Bio-derived bone scaffold was implanted into the left radius, serving as the controls, without any fixation. No implant was given into the other 5 rabbits as the blank group. MAIN OUTCOME MEASURES: X ray and histological examination was performed to compare the union of fracture on 3 groups. RESULTS: X ray showed that bony callus gradually increased when time went by, the fractures almost healed 8 weeks after operation in the experimental group and the moulding finished 12 weeks postoperation. Much less bony callus was observed and union time of fracture was longer in the control group. No bone defects were repaired and nonunion occurred in the blank group 12 weeks postoperation. X ray evaluation indicated new bone formation in the control group was significantly less than that in the experimental group (P < 0.05) at 2, 4, 8, 12 weeks postoperation. Histological examination indicated the scaffold began to be absorbed 4 weeks postoperation, was reconstracturred by new bone 8 weeks postoperation, and completely repaired 12 weeks postoperation in the experimental group. These symptoms were delayed obviously in the control group. Histological evaluation indicated new bone formation and formed volume in the control group were significantly less than those in the experimental group (P < 0.05) at 2, 4, 8, 12 weeks postoperation. There was no new bone formed in the control group, and the bone defects were filled with the fibrous tissues. CONCLUSION: The induced bone marrow stromal stem cells can be combined with bio-derived bone to construct a tissue engineered bone. It quickly promotes the new bone formation for the repair of large segmental radial defects in rabbits, and its repair capability is better than that of bio-derived bone alone.