生长期兔颞下颌关节盘前移位后髁突软骨胶原表达的变化

目的:建立生长期兔颞下颌关节不可复性关节盘前移位动物模型,检测髁突软骨内Ⅱ型胶原和X型胶原的表达,探讨青少年颞下颌关节盘不可复性前移位与髁突软骨内成骨的关系,及其与下颌骨发育不对称畸形之间存在相关性的机制.方法:取生长期新西兰大白兔40只,右侧颞下颌关节手术建立不可复性关节盘前移位模型,左侧行假手术作为对照.实验动物于建模后24 h、1、4、8、12周分组处死取材.通过免疫组织化学方法检测髁突软骨组织内Ⅱ型胶原和X型胶原在蛋白水平的表达,采用PASW statistics 18.0软件包对每组样本实验侧和对照侧进行配对t检验.结果:Ⅱ型胶原在盘移位后24h、1、4、8周时与对照侧均无显著差异,12周时较对照侧表达升高(P＜0.05).X型胶原在盘移位后24 h(P＜0.01)、1周(P＜0.01)、4周(P＜0.05)时较对照侧显著降低,8周、12周时实验侧与对照侧间无显著差异.结论:不可复性关节盘前移位对兔髁突软骨内成骨过程造成干扰,这种影响可能是单侧颞下颌关节盘前移位后患侧下颌支高度不足和下颌骨不对称畸形的重要原因.

Changes of collagen expression in condylar cartilage of growing rabbits with anterior temporomandibular disc displacement

PURPOSE：To establish an animal model of surgically induced anterior disc displacement（ADD） without reduction in growing rabbit and semi-quantitatively assess the changes in expression of type Ⅱ collagen and type X collagen with immunohistochemistry after ADD without reduction,so as to explore the effect of surgically induced ADD upon endochondral ossification of the mandibular condyle and the mechanism of mandibular asymmetry.METHODS：Surgically induced ADD without reduction was performed in 40 growing rabbits in the right side of temporomandibular joint（TMJ）,while a sham operation was performed in the left side.The animals were sacrificed at 24-hour,1-,4-,8-,and 12-week after surgery.Immunohistochemical staining of type II collagen and type X collagen was performed in the condylar cartilage specimen.The data was analyzed for paired-t test using PASW statistics 18.0 software.RESULTS：The expression of type Ⅱ collagen had no significant change at 24-hour,1-,4-,and 8-week after surgery and increased at 12-week（P＆lt;0.05）.The results showed that expression of type X collagen significantly decreased at 24-hour（P＆lt;0.01）,1（P＆lt;0.01）,and 4-week（P＆lt;0.05）,but had no significant difference at 8-,and 12-week after surgery.CONCLUSIONS：The results of this study suggest that surgically induced ADD has an adverse effect on condylar endochondral ossification in early period in growing rabbits.It might be the causes of shortening of mandibular ramus and asymmetry of mandible after surgically induced ADD.