兔同种异体眶骨移植研究

Experimental study of implanting orbital bone allografts in rabbits

目的探索兔同种异体眶骨植入眶骨缺损的可行性和有效性。方法日本大耳白兔24只,8只兔用于制备经深低温冷冻同种异体眶骨,16只兔通过手术造成双眼眶上壁15 mm×5 mm×2 mm大小的骨缺损模型,左右眼眶上壁分别植入同种异体眶骨和自体骨。植入同种异体骨的一侧眼眶设为实验组,对侧植入自体骨为对照组。术后2、4、8、12周处死实验兔后分别进行大体观察、CT检查、组织学检查及免疫组织化学染色测定骨形态发生蛋白-2(BMP-2)的表达。结果 2组切口愈合良好,术后第2周、第4周,2组愈合情况未见明显差异;术后第8周、第12周,实验组2例未愈合,对照组愈合程度好于实验组,植入骨与宿主骨已成一整体。影像学检查:术后分别在2、4、8、12周测得植入骨与宿主骨结合部平均CT值对照组均高于实验组。组织学检查:术后第2周、第4周,植入骨与宿主骨可见大量炎性细胞浸润,新生骨痂形成,2组无明显差异;术后第8周、第12周,对照组新骨形成较实验组多。免疫组织化学染色测定BMP-2的表达:术后第2周、第4周,异体骨周围的骨痂中可见阳性表达,术后第8周、第12周,异体骨、皮质骨及周边成熟的骨单位可见阳性表达。结论兔同种异体眶骨在眶骨组织缺损修复中与自体骨移植形成骨性愈合程度接近,在修复眶骨组织缺损中效果较好。

Background Orbital bone defect results in not only deformation in appearance but also abnormal function of eyeball.Bone allografts as implanted materials have been widely applied in orthopedic basic and clinical research,but there is only a little literature about restoring orbital bone defect so far.ObjectiveThis study aimed to evaluate the effectiveness and feasibility of bone allografts as implanting materials for restoring orbital bone defect.MethodsThe orbital bone defect models were created in both eyes of 16 Japanese White rabbits by removing the superior orbital wall with the size of 15mm×5mm×2mm.The deep cryopreservated orbital meterials from other 8 matched rabbits were implanted into the defect area in 8 model rabbits as the allograft group,and the removed orbital bones were recovered in the fellow eyes as the autograft group.CT scaning was perfomed at 2,4,8 and 12 weeks respectively and the models were sacrificed for the examinations of gross specimen and histological pathology examination.Expression of bone morphogenetic protein-2（BMP-2） in bone grafts was detected at 2,4,8,12 weeks respectively using immunohistochemistry.ResultsIn 2-4 weeks after surgery,the healing degree of grafts and host bone in allograft group was similar to that of autograft group.The grafts connected well with the host bone and formed a whole body in 12 eyes of allograft group 8-12 weeks later,but the bone healing was better in autograft group.The average CT numerical value in connecting zone of graft and host bone was insignificantly higher in autograft group compared to allograft group in various time points（P0.05）.Histological examinations showed that a lot of inflammatory cells and fresh callus were seen in binding area of grafts and host bone in both allograft and autograft groups and the Haversian system on the new bone could be seen from 2 weeks through 4 weeks after surgery,and the new bone was more in autograft group than the allograft group from 8 through 12 weeks.BMP-2 was positively expressed in osteoblasts and callus from 2 weeks through 8 weeks and in cortical bone and surrounding mature osteon in 12 weeks after surgery in allografts group.The positive expression in bone tissue was also seen through the experimental duration in autograft group.ConclusionThe forming-bone healing procedure between orbital bone allograft and autograft is similar.The allograft of orbital bone is feasible and effective for the repair of orbital bone defect in rabbits.