颞下颌关节盘前移位对髁状突软骨中纤溶酶原激活剂系统表达的影响

THE EFFECT OF ANTERIOR DISC DISPLACEMENT ON THE EXPRESSION OF UROKINASE PLASMINOGEN ACTIVATOR SYSTEM IN RABBIT CONDYLAR CHONDROCYTES

目的研究颞下颌关节盘前移位对关节软骨组织中尿激酶型纤溶酶原激活剂(uPA)系统的影响。方法24只日本大耳白兔在不打开关节囊的情况下建立右侧颞下颌关节盘前移位动物模型,分别于术后4、1、2、4、8d和12周各处死4只动物。常规HE染色观察髁突软骨的形态学变化,并以原位杂交法检测髁突软骨细胞中uPA和纤溶酶原激活剂抑制剂-1(PAI-1)的基因表达变化。结果术后髁突受力区出现一过性的软骨变薄、各层排列紊乱等病理变化。uPA和PAI-1基因转录水平在术后即开始上调,至2周时达到最高水平,至12周时基本恢复至正常水平,与髁突软骨的适应性改建相一致。结论颞下颌关节盘前移位后,关节软骨内uPA系统的变化与关节软骨的适应性改建密切相关。

Objective To study the effect of anterior disc displacement on the expression of urokinase plasminogen activator（uPA） system in rabbit condylar chondrocytes. Methods The anterior disc displacement of right TMJs was established in 24 rabbits without the exposure of joint capsule. Four of the 24 rabbits were killed at 4 days or 1,2,4,8 and 12 weeks after surgery respectively. The histological changes of condylar cartilage by hematoxylin-eosin staining were studied. In situ hybridization techniques was used to evaluate the changes of mRNA of uPA and its type-1 inhibitor （PAI-1） in condylar chondrocytes. Results After disc displacement, transient pathological changes, such as thinning of cartilage and disarrangement of layers in condylar cartilage, were found in the condyle where suffered the load of mastication. The expressions of uPA and PAI-1 mRNA increased immediately and reached the highest level at two weeks. After it began to decline gradually and reached nearly normal level at 12 weeks. These changes were coincided with the remodeling in condylar cartilage. Conclusion Urokinase plasminogen activator system is correlated with the remodeling in condylar cartilage after disc displacement.