生长期山羊颅骨缝受牵张力作用后超微结构与免疫组化观察

The changes of cranial suture induced by the distraction forces in growing goats

目的研究生长期山羊颅骨冠状缝受牵张力作用后组织与细胞结构的变化。方法选用生长期山羊,在颅骨冠状缝两侧安放自行研制的牵张器。实验组动物按0.4mm/d的速率进行骨缝牵张。在牵张结束后第0,2和4周分3组取骨缝标本进行X线摄像,扫描电镜及BMP与TGF-β免疫组织化学观察。未进行骨缝扩张的动物作为对照。结果实验组动物的冠状缝均被成功分离。牵张结束后0与2周,扩大骨缝中可见胶原纤维沿牵张力方向有序排列,骨缝边缘出现大量成纤维细胞和成骨细胞,BMP和TGF-β在这些增殖活跃的细胞中呈高水平表达。第4周,受力骨缝边缘以膜内成骨方式进行改建,BMP和TGF-β阳性染色主要位于新生骨小梁四周的成骨细胞中。结论牵张成骨技术可以顺利扩张处于生长期动物的颅骨缝,BMP和TGF-β可能在颅骨缝牵张成骨过程中扮演重要调控角色。

Objective： To observe the response and changes of cranial suture to the distraction forces in growing goats. Methods ： A custom-made distractor was used for expanding coronal suture of 11 growing goats at the rate of 0.4 mm/day for 8 days. The animals were killed 0,2 and 4 weeks respectively after completion of suture distraction application. X-ray examination was taken and the distracted suture samples were harvested and processed for scanning electron microscopic observation and immunohistochemistry examination of BMP and TGF-β expression. The coronal sutures taken from other undistracted animals were used as the controls. Results： The coronal sutures were separated successfully in distracted goats. 0 and 2 weeks after application of suture distraction, the collagen fiber bundles were strengthened and aligned in the direction of the distraction. Strong expression of BMP and TGF-β were detected in the fibroblast-like cells and the active osteoblasts. 4 weeks after suture distraction, signs of intramembranous ossification were found in the edge areas of the distracted suture, and the positive staining of BMP and TGF-β was still noted in the osteoblasts around the newly formed bone trabeculae. Conclusion：BMP and TGF-β may play important roles in the process of bone formation and remodeling during suture distraction osteogenesis.