自体骨膜活化多孔陶瓷块修复长骨干缺损的实验研究

REPAIRING SEGMENTAL BONE DEFECTS WITH LIVING POROUS CERAMIC CYLINDERS: AN EXPERIMENTAL STUDY IN DOC FEMUR

目的:利用自体骨膜中所含成骨细胞及生长因子与多孔生物活性陶瓷复合,制备一种活化的骨替代材料,修复长骨干缺损。方法:从21只狗的股骨干上切取骨膜片,吸附包裹于25cm长1.5Cm、直径1.2Cm、中心有一孔的柱状陶瓷块表面;然后植入自体股部肌群内,1月后将其中4块取出作组织学观察,了解异位成骨情况。另21块直接移植替代相应大小的股骨干缺损。分别于2月、4月、6月取出替代骨段(含材料及相临骨组织)作生物力学测定、X线衍射分析和组织学观察。结果:植入肌内1月时,陶瓷块表面的骨膜增生变厚,骨膜-材料界面成骨细胞大量增生并向陶瓷空隙内爬行,可见新骨形成。植入骨缺损后,随时间延长,抗弯强度逐渐增加,6月时已接近正常骨的抗弯强度。X线衍射分析提示,2月时TCP迅速降解,6月时的X线转靶谱图已接近自体骨。组织学观察,2月时新生骨组织迅速增加,植入物与上下骨面融合。4月和6月时,大部分材料为新生骨组织所替代,新骨比例远大于陶瓷材料,植入物内大量骨小梁形成,哈佛系统清晰可见,成熟骨组织充满材料的孔隙并相互连接。结论:实验结果提示,用自体骨膜与双相多孔陶瓷复合在自体内培养,可使骨膜中的生长因子及成骨细胞活跃,从而提高陶瓷材料的生物活性,用于修复长骨干缺损可加速新骨形成,达到负重骨替代的目的。

Objective:To produce a living bone substitutive material used in repairing segmental bone defects. Method: 25 cylinders 1.5cm in length and 1.2 in diameter made of porous HA - TCP ceramic were swathed with fresh autogenetic periostea of 21 dogs and then implanted in the same animals' muscles to get living ceramic bone substitutes containing autogenetic growth stimulators. One month later, the cylingders were harvested and 21 of 25 cylingders were implanted directly to the segmental bone defect sites created in femora of the same animls, too. The other four cylinders were picked out for histomorphological observation to demonstrate the living potential of the material and periostea in heterosites. Then the dogs were divided into three groups of 2, 4 and 6 month group, respectively. Result: The roentgenograms showed that in pace of time, the boundaries between the cylinder and bone became vague gradually. XRD analysis indicated the peaks of TCP in the material got weaker and the XRD graphs of the samples tended to be similar with natural bones by six months postoperatively. The values of bending strenght also enhanced gradually and showed significant variation between the tliree groups (p<0.05) .Histologically, in the samples implanted in muscles, a great of osteoblasts and fibrobiasts could be observed between the interfaces of ceramic cylinders and surrounding periostea, some of them aggregated on the walls of the ceramic pores. It was also seen that these cells crept into the center areas of the cylinders. Occasionally, dispersed newly formed bone tissues containing a few trabeculae could be discovered under microscope. After transferred to the bone defect sites, the newly formed bone tissues rapidly in- creased and the cylinders gradually fused with the contacted bones two months later.By four and six months, bone issues replaced most areas in the materials. The ratio of newly formed bone tissues held a big lead over the materials. Harversian system were clearly observed and matured bone tissues filled the ceramic pores and connected each other. Conclusion: All result suggest that culturing complexes consisted of growth factors in autogenetic periostea together with biomaterials taking advantage of living organic culturing medium should be an effective approach to get satisfied bioactive bone substitutes. It is also provided the basis for clinically repairing bone defects in bearing sites with complex bioceramics.