活性纳米羟基磷灰石复合胶原/聚乳酸材料修复颅骨极限缺损的实验研究

目的检测重组人骨形成蛋白2(recombinant human bone morphogenetic protein2,rhBMP-2)与纳米羟基磷灰石/胶原/聚乳酸(nano-hydroxyapatite/collagen/polylactic acid,nHAC/PLA)复合后形成的活性nHAC/PLA(active nHAC/PLA,AnHAC/PLA)修复颅骨极限缺损的效果。方法新西兰大白兔48只,体重2.0～2.5kg。制备直径为15mm的颅骨全层缺损模型,随机分成4组,每组12只。阳性对照组:缺损区植入自体髂骨;空白对照组:缺损区不植入任何材料;阴性对照组:缺损区植入nHAC/PLA;实验组:缺损区植入AnHAC/PLA,每块AnHAC/PLA上平均吸附rhBMP-21.431mg。术后8、16周通过比较颅骨缺损区X线阻射面积占总缺损面积百分比、HE染色和Masson's三色法染色观察颅骨极限缺损的修复情况。结果术后8、16周,各组颅骨缺损区X线阻射程度,阳性对照组分别为67.21%±2.06%、86.48%±1.73%,空白对照组分别为5.84%±1.92%、9.48%±2.72%,阴性对照组分别为19.13%±2.51%、35.67%±3.28%,实验组分别为58.84%±2.55%、85.61%±3.36%。其中除16周实验组与阳性对照组以及空白对照组8、16周比较差异无统计学意义(P>0.05)外,其余各组各时间点比较差异均有统计学意义(P<0.05)。组织学观察显示,阳性对照组骨缺损区16周骨小梁较8周增宽,被大量骨组织充填;空白对照组8、16周骨缺损区均被纤维组织充填,无新骨生成;阴性对照16周骨缺损区为剩余材料与纤维组织充填,周边新骨较8周形成增多;实验组8周材料植入区为新生骨替代,16周新生骨呈板层状,缺损区材料残留较少,且周围可见较多成骨细胞。结论nHAC/PLA是rhBMP-2的良好载体,两者复合后制备的AnHAC/PLA具有良好骨形成能力,有望应用于临床上修复较大型骨缺损。

STUDY ON REPAIR OF CRITICAL CALVARIAL DEFECTS WITH NANO-HYDROXYAPATITE/COLLAGEN/POLYLACTIC ACID MATERIAL COMPOUNDED RECOMBINANT HUMAN BONE MORPHOGENETIC PROTEIN 2 IN RABBITS

OBJECTIVE: To investigate the effect of tissue engineering bone compounded in vitro by nano-hydroxy-apatite/collagen/polylactic acid (nHAC/PLA) and recombinant human bone morphogenetic protein 2 (rhBMP-2) in repairing rabbit critical calvarial defects. METHODS: Forty-eight New Zealand rabbits, weighting 2.0-2.5 kg, were made the models of critical cranial defects (15 mm in diameter) and divided into 4 groups randomly. Defects were repaired with auto-flank bone in the positive control group; with no implant in the blank control group; with nHAC/ PLA in the negative control; and with active nHAC/PLA(AnHAC/PLA) in the experimental group(the average quality of each AnHAC/PLA absorbed rhBMP-2 was 1.431 mg). The reapir results were observed through X-ray,HE dyeing and Masson's trichrism dyeing after 8 and 16 weeks. RESULTS: The difference of bone formation was observed by X-ray block degree of skull defect area at 8 and 16 weeks. In the 8 th week and 16 th week, the radiopacities on cranial defect were 67.21%+/-2.06% and 86.48%+/-1.73% in the positive control group; 5.84%+/-1.92% and 9.48%+/-2.72% in the blank control group; 19.13%+/-2.51% and 35.67%+/-3.28% in the negative control group; and 58.84%+/-2.55% and 85.61%+/-3.36% in the experimental group. There were significant differences between the negative control and the positive control group, and between the experimental group and the positive control group at 8 weeks (P<0.05). There were significant differences between the negative control and blank group, and between the experiment and the blank group at 8 and 16 weeks (P<0.05). The histology observation showed that the width of bone trabecula at 16 weeks was more than that at 8 weeks and bone defect was full of bone tissue in positive control group. The bone defect was full of fibrous tissue at 8 and 16 weeks, and there was no new bone in the blank group. The bone defect was full of remnant material and fibrous tissue in the negative control group. The implanted area was replaced by the new bone at 8 weeks and the new bone was lamellar at 16 weeks in the experimental group; the residual material was less in defect area and there were more osteoblasts surrounding. CONCLUSION: The nHAC/PLA is a good scaffold material of rhBMP-2 and AnHAC/PLA has a good ability in repairing bone defect. So it is hopeful to be applied in the clinical repair of large bone defect.