上颌骨内置式持续等张缝牵引成骨机制的实验研究

Experimental studies of isotension continuous sutural distraction osteogenesis mechanism on maxillary complex

目的:通过对山羊颧上颌缝持续等张缝牵引成骨来延长上颌骨复合体,探讨缝牵引成骨的机制。方法:在山羊两侧颧上颌缝安置自主设计制作的内置式微型自动持续等张缝牵引器,缝两侧钛钉标记,术后定期拍摄X线片,并在4、6、8周切取牵引和未牵引的颧上颌缝及新生骨组织,进行组织学观察。采用免疫组化染色方法研究标本中bFGF、TGF-β1、VEGF的表达和变化。结果:在牵引力的作用下,所有山羊上颌骨复合体均成功前徙。在牵引6周时出现软骨细胞团,细胞团之间有新生骨小梁形成。间充质细胞、成骨细胞及骨细胞中bFGF、TGF-β1、VEGF均有不同程度的阳性表达或阳性表达增加,呈时间和空间上的变化。结论:经缝牵引成骨的成骨机制以膜内成骨为主,但也有软骨成骨;bFGF、TGF-β1、VEGF以及3种胶原均参与了缝牵引成骨的成骨过程,促进了间充质细胞向成骨细胞的增殖、分化及新骨的改建。

Objective To study the mechanism of bone formation by observing the histology changes and bFGF、TGFβ1、VEGF expressions in zygomatico-maxillary suture and new bone tissue.Methods Use goats as experimental animals,several self-designed internal nickel-titanium shape memory metal braces were placed on maxillary surface,by taking X-ray regularly after operation to show the exact distances that maxilla moved.Then the new bone and suture tissue were obtained in 4weeks,6weeks and 8weeks after distraction to observe the histology changes and collagen changes through microscope.The expressions of bFGF、TGF-β1、VEGF were investigated by means of immunohistochemistry.Results All goats＇ maxillary complex advanced successfully.Six weeks after distraction,the newborn cartilage cell group appears,and between the cartilage cell group there were forming new bone trabeculas.bFGF、TGF-β1、VEGF expressed in all groups and varies with distracting time.Conclusions Cartilaginous osteogenesis participate in bone formation in the sutural tissue.On the surface of the maxilla,main mechanism of bone formation is intramembranous osteogenesis,bFGF、TGF-β1、VEGF and all three types of collagen take part in the bone regeneration.