一种新型的Ⅲ类矫形力装置的大鼠动物模型建立

Establishment of New Class Ⅲ Orthopedic Animal Model on the Growing SD Rat

目的:建立新型的牵引下颌向后的大鼠动物模型,评价动物模型的成功性。方法:自主设计大鼠颅骨颌面支架装置,将牵引钩粘接于大鼠的下切牙上,与支架进行Ⅲ类牵引,对下颌骨颞下颌关节施加向后、向上的压力,力值约为40g,时间为0、3、7、14、21d;采用X线片、相片、HE染色、透射电镜以及Micro CT对大鼠髁突软骨进行影像学、组织形态以及超微结构学的观察。结果:加力后大鼠下颌就出现后退的变化,覆盖明显增大。HE结果显示,加力后大鼠髁突软骨厚度出现明显的变薄和软骨细胞的减少。透射电镜的结果进一步验证了组织形态学的改变,增殖层细胞出现顺应力场方向的改变;Micro CT观察到软骨的变薄和骨小梁的应力样改变。结论:该模型能有效的牵引下颌向后,是较为理想的研究Ⅲ类矫形力作用机制的动物模型;压应力刺激下髁突软骨在组织形态和超微结构上均有明显的改变。

Objective： To establish a new animal model on the growing SD rat to pull mandible back.Methods： The anchorage advice on rat was self-made,and the elastic hook was bonded on rat lower insicors.40 g of Class Ⅲ orthopedic force was exerted on temporo-mandibular joint through the anchorage and the elastic hook for 0,3,7,14 and 21 days.The X ray,histology,ultrastructure change and micro CT were observed to evaluate the effect of animal model.Results： The results showed that mandible was in the back position and over jet was increased.The histological change demonstrated that the thickness of each zone and number of chondrocytes were significantly reduced.Chondrocytes morphological changes were observed under TEM.Micro CT showed the thinning cartilage and trabecular bone mechanical changes.Conclusion： The new class Ⅲ orthopedic animal model was established successfully to exert a compressive force on TMJ.The significant changes in histology and ultrastructure were demonstrated by using this model.