双侧下颌牵张成骨对转化生长因子β1在颞下颌关节髁突表达的影响

The Effect of Dog Bilateral Distraction Osteogensis in Temporomandibular Joint

目的 研究狗的双侧下颌牵张成骨中颞下颌关节髁突的形态改变及转化生长因子β1(TGF_β1)在髁突的 表达。方法 16只狗随机分为4组,每组4只,分别为牵张6d组、牵张后固定2周组、牵张后固定8周组及正常对 照组。各实验组的牵张频率均为1mm d,1次 天。对每组动物的髁突标本进行苏木精-伊红染色及TGF_β1的免 疫组化染色观察。结果 苏木精-伊红染色可见实验组动物的髁突纤维软骨早期有不同程度的损伤,增殖带、肥 大带细胞增生活跃,软骨钙化层及其深层软骨成骨活跃;TGF_β1阳性染色主要定位在肥大带细胞胞浆、周围基质和 成骨反应活跃处的成软骨细胞、成骨细胞及周围基质。牵张后固定2周时这种改建修复现象最明显,8周时逐渐恢 复至正常对照组的表现。结论 双侧下颌牵张成骨对颞下颌关节髁突影响主要表现为髁突纤维软骨组织形态学 的改变和软骨、骨的改建活动,但随着固定时间的延长这种改变逐渐修复。

Objective To investigate the effect of bilateral mandibular distraction osteogenesis in the condyles.Methods 16 adult hybrid dogs were randomly divided into normal control group and experiment group. Experimental dogs underwent bilateral mandibular osteodistraction at a rate of 1 mm/day. 4 dogs were killed respectively in distraction period, 2 and 8 weeks after completion of 10 days distraction. The bilateral condyles specimens were harvested and examined with histological and immunohistochemical methods.Results Compared with normal control group, various degrees of irregularities and erosion were found in fibrocartilage of condyle in experiment group, including damage in fibrous layer, hyperplasia layer and proliferative layer and osteogenic activity in cartilage layer. A significant increase of TGF-β1 expression was also found in experiment groups. TGF-β1 positive staining was noted in hypertrophic cell, matrix and chondroblast, osteoblast and matrix in osteogenic activity areas. These changes were the most obvious in 2 weeks after completion of distraction.Conclusion Gradual bilateral mandibular distraction at a rate of 1 mm/day brought degenerative changes of condyle, but the changes are reversible.