rhBMP-2膜联合PDLLA-nano/HA夹板、螺钉固定促进兔下颌骨骨折愈合的实验研究

An experimental study of recombinant human bone morphogenefic protein 2 membrane and PDLLA-nano/HA plates and screws treating mandibular fractures of rabbits

目的探讨rhBMP-2在可吸收PDLLA-nano/HA夹板、螺钉固定的骨折愈合中的作用效果。方法每只兔随机选取一侧下颌骨造成垂直于体部的完全骨折，分别采用PDLLA-nano/HA夹板固定组、PDLLA-nano/HA夹板固定后加入不含rhBMP-2的胶原膜组及用PDLLA-nano/HA夹板固定后加入含rhBMP-2的胶原膜组。分别于术后不同时段进行大体观察、X线检查和HE染色观察。结果各组动物伤口均Ⅰ期愈合，骨折无移位，咬合正常，X线显示由2周至12周，骨折线逐渐由清晰变为模糊最后消失，但加入rhBMP-2组比另2组在同一时间段骨折线密度更高。HE染色示在早期（2-4周）rhBMP-2组即有大量成骨细胞和成软骨细胞及新生骨样组织。12周rhBMP-2组骨折线不可见，骨小梁走向趋于规则，不含rhBMP-2的2组骨小梁呈网状，不如rhBMP-2组规则，骨折线模糊。结论PDLLA-nano/HA夹板是一种优良的骨折内固定材料，加入rhBMP-2后，骨折愈合得更快、更好。

Objectives To investigate the role of recombinant human bone morphogenetic protein 2 （rhBMP-2） in the healing of mandibular fractures of rabbits. Methods 36 healthy adult New Zealand rabbits were random divided into 4 time intervals （ 2, 4, 8 and 12 weeks after operation） and 9 rabbits in each time interval were classified into 3 groups. Every rabbit was operated to create a fracture by means of osteotomy in the body of mandible. Then 3 rabbits in the first group were fixed with PDLLA-nano/HA plates only. The second group was fixed with PDLLA-nano/HA plates and the sites of osteotomy were coated with collagen sponge without rhBMP-2. The third group was fixed with PDLLA-nano/HA plates and the sites of osteotomy were coated with collagen sponge with rhBMP-2. The rabbits were sacri- ficed at the 2nd, 4th, 8th and 12th weeks after operation respectively. Then the mandibles were picked up and taken X ray radiographs. Consequently, specimens were processed in the routine method to produce paraffin sections. Then some sections were dyed with HE method to appraise the outcome of healing. Results General observation showed that all incisions healed normally. The occlusions of rabbits were normal. There were no plates deviating from original sites. X ray result showed that the fractures healed in rhBMP-2 group were faster than that in the other two groups at the 2nd, 4th and 8th weeks after operation. HE sections showed that bone formation was most remarkable in rhBMP-2 group in all time intervals. Conclusion Combination of PDLLA-nano/HA plate and rhBMP-2 can accelerate the healing of mandibular fractures of rabbits.