预构骨肌皮瓣修复下颌骨和皮肤复合缺损的实验研究

目的 探讨BMP-2与胶原复合材料在骨骼肌中异位成骨预构骨肌皮瓣,修复自体下颌骨和皮肤复合缺损的可行性. 方法 4～6周龄新西兰白兔24只,体重2.0～2.5 kg,雌雄不拘,随机分成3组,即实验组、对照组和空白组(n=8).将BMP-2与胶原复合,植入兔背阔肌,预构异位新生骨组织,2、4、6周后行X线片、ALP、Von Kossa、CD31免疫组织化学血管标记及组织学观察.6周后,实验组动物于同侧下颌骨体部制备2 cm × 3 cm皮肤缺损,并形成直径8 mm洞穿性骨缺损;以同侧胸背动脉体表投影为皮瓣纵轴,设计含预制新骨组织的背阔肌肌皮瓣,带蒂移位修复下颌骨及皮肤复合缺损.对照组和空白组实验动物下颌骨体部均造成直径8 mm的洞穿性骨缺损,对照组将复合组织瓣中的骨性部分游离移植修复缺损;空白组缺损不予修复.术后6周,各组取材行四环素荧光染色、X线摄片、组织学观察以及新骨计量等,观察骨和皮肤复合缺损修复效果. 结果 BMP-2与胶原复合材料在兔背阔肌中4～6周成骨,胶原材料于植入后3～5周降解,成骨过程以软骨成骨为主,新骨形态为编织骨,可见明显的微血管分布.修复自体下颌骨缺损6周后,实验组皮肤及骨缺损均愈合良好,对照组缺损修复区基本骨化,空白组尚残留大块骨缺损实验组、对照组及空白组新骨计量分别为(1.594 ±0.674)、(0.801 ±0.036)和(0.079±0.010)mm2,组间两两比较,差异均有统计学意义(P＜0.05). 结论 预构的骨肌皮瓣带血管蒂移位修复兔自体下颌骨和皮肤复合缺损具有可行性和明显优势,有望成为一种血管化骨移植的供区预构形式.

EXPERIMENTAL STUDY ON REPAIRING COMPOSITE DEFECT OF MANDIBLE AND SKIN BY PREFABRICATED MUSCULOCUTANEOUS FLAP INCLUDING ECTOPIC BONE

OBJECTIVE: To evaluate the effect on repairing composite defect of mandible and skin by prefabricated musculocutaneous flap including ectopic bone induced by BMP-2 and cdllagen in rabbits' latissimus dorsi muscle. METHODS: Twenty-four rabbits (4-6 weeks old) were randomly divided into 3 groups: experimental, control and blank control group (n = 8 in each group). Composite carriers composed of BMP-2 and collagen I sponge were implanted into latissimus dorsi muscle pouches of rabbits. The bone formation was evaluated with roentgenography, ALP staining, Von Kossa staining, HE staining, toluidine blue staining and CD31 immunohistochemical labelling of microvessels. After 6 weeks, the mandibular defect of 8 mm in diameter with local skin defect of 2 cm x 3 cm was made in experimental group, and a musculocutaneous flap including ectopic-induced bone was prefabricated to transfer and repair the composite defect. The mandibular defect of 8 mm in diameter without local skin defect was made in control and blank control group. Free ectopic-induced bone was used for the repair of mandibular defect in control group, but repairing was not performed in blank control group. All the samples were detected 6 weeks after operation for tetracycline fluorescent staining, X-ray, histological examination and bone quantity analysis to evaluate the effect. RESULTS: Bone formation induced by BMP-2/collagen composites were found as woven bone between 4 to 6 weeks. It showed that cartilaginous osteogenesis was the mainly type of bone formation. Microvessels could be seen in the bony tissues. The composite defects of mandible and skin were healed well in the experimental group. Major bony tissue were seen in the control group, while it still remained bony defect in the blank control group. The bone quantity analysis in the experimental, control, and blank control group were (1.594 +/- 0.674), (0.801 +/- 0.036), and (0.079 +/- 0.010) mm2, there were significant differences between each groups (P < 0.05). CONCLUSION: Prefabrication of musculocutaneous flap including bone induced by the composite of BMP-2 and collagen is feasible and prevalent. It can be regarded as vascularized bone graft and used in repairing composite defect of bone and skin.