前列腺素E2复合同种异体骨治疗实验性骨缺损

背景：前列腺素E2具有促进骨生长的作用，其与同种异体骨移植块复合能否加速骨缺损的修复有待进一步证实。目的：观察复合前列腺素E2的同种异体冻干骨移植用于治疗兔实验性骨缺损的疗效，并探讨其作用机制。设计、时间及地点：随机对照动物实验，于2008-11/2009-03在华中科技大学同济医学院附属梨园医院老年病研究室完成。材料：健康雄性新西兰大耳白兔46只，体质量(1.8±0.2) kg，其中6只新西兰大耳白兔取髂骨和肩胛骨以截取骨组织块，深低温冷冻干燥灭菌后经0.01 mg/L和0.1 mg/L前列腺素E2深低温冷冻干燥复合24 h。方法：40只大耳白兔按数字表随机分为自体骨移植组，异体骨移植组，0.01 mg/L前列腺素E2骨移植组和0.1 mg/L前列腺素E2骨移植组，每组10只。无菌条件下切除桡骨中段1.5 cm骨干和骨膜建立骨缺损实验模型，后分别移植自体骨组织块，异体骨组织，0.01 mg/L前列腺素E2异体骨组织块和0.1 mg/L前列腺素E2异体骨组织块复合。主要观察指标：术后4周进行患处的骨影像学、组织学检测，测定钙含量及骨形态发生蛋白2表达水平。结果：前列腺素E2复合的异体骨组织块移植修复骨缺损明显优于未处理的异体骨组织块，局部钙含量和骨形态发生蛋白2表达明显增高，且这些作用呈浓度相关性。骨影像学显示自体骨的骨痂形成速度快于异体骨，而前列腺素E2骨移植组的骨痂形成速度较自体骨移植组快，并与前列腺素浓度呈正相关。组织学检测显示自体骨的骨小梁形成数目多于异体骨，而复合组除了骨小梁形成之外，还有大量的成骨细胞、骨细胞形成，且新生毛细血管丰富。结论：前列腺素E2复合的异体骨组织块移植能促进骨缺损的愈合，其作用机制可能与增强骨形态发生蛋白2的表达有关。

Effect of allograft bone combined with prostaglandin E2 on experimental bone defects

BACKGROUND: Prostaglandin E2 (PGE2) has beneficial effect to promote bone growth. However, whether the allograft bone combined with it could promote the repair of bone defect needs further explored. OBJECTIVE: To investigate the effect of allograft bone combined with PGE2 on experimental rabbit bone defects, and to explore the underlying mechanism.DESIGN, TIME AND SETTING: Randomized controlled animal experiment was performed at the Senile Disease Laboratory of Liyuan Hospital, Tongji Medical College of Huazhong University of Science & Technology from November 2008 to March 2009.MATERIALS: A total of 46 healthy New Zealand male rabbits were involved, weighing (1.8±0.2) kg. The iliac and scapula bone tissues were obtained from six rabbits, followed by profound hypothermia frozen dry and sterilization, subsequently combined with 0.01 mg/L and 0.1 mg/L PGE2 for 24 hours in the freeze drying condition.METHODS: The midpiece of radial bone defect models at 1.5 cm long bone shaft and periosteum were established on forty New Zealand rabbits under sterile conditions. They were randomly separated into four groups of ten animals and transplanted with autograft bone, allograft bone, allograft bone combined with 0.01 mg/L PGE2 and allograft bone combined with 0.1 mg/L PGE2, respectively. MAIN OUTCOME MEASURES: Four weeks after the transplantation, the radiographic and histological detections were carried out. Content of calcium and bone morphogenetic protein-2 (BMP-2) protein expression level in local defect area were determined respectively. RESULTS: The allograft bone combined with PGE2 significantly repaired the bone defect comparing with the allograft bone without any treatment. The local content of calcium and BMP-2 protein expression increased with the allograft bone combined with PGE2. All these effects were in dose-dependent manner. The radiographic detections showed that the formation of bone callus in autologuous groups were faster than that of allograft groups. The allograft bone combined with PGE2 had a faster formation of bone callus than autologous groups, and PGE2 concentrations were positively correlated with the speed of recovery of bone defect. Histological detections proved that the autologous group presented more trabecula than allograft groups, and for the allograft bones combined with PGE2, there were a large number of osteoblasts, osteocytes, and abundant new capillaries in addition to the formation of more trabecula.CONCLUSION: With the combination of PGE2, allograft bone could effectively promote the recovery of bone defect. The mechanism is possibly related to the increasing protein expression of BMP-2.