颞下颌关节盘前移位关节盘及盘后区超微结构变化的实验研究

目的通过建立关节盘前移位实验动物模型的方法,研究颞下颌关节盘前移位后关节盘及盘后区早期超微结构的变化。方法10只兔左侧关节经手术诱导为关节盘前移位模型,右侧为手术对照组;2只为正常对照组。术后24小时、1周、2周、3周、4周,麻醉下活体各切取2只手术组实验动物同一部位的关节盘和关节盘后区组织,制成透射电镜标本观察。结果关节盘组织中软骨样细胞逐渐增多,细胞周围的淡区逐渐变小并消失,胞浆中微丝增加,胶原纤维间排列紊乱数量减少,并见新生毛细血管及神经纤维,最后软骨样细胞转化为纤维母细胞和肌纤维母细胞。盘后区早期出现幼稚的软骨样细胞,有排列相对致密的胶原纤维,最后转化成类似于关节盘样组织。结论颞下颌关节盘前移位后,关节盘失去纤维软骨盘的特性转化为纤维结缔组织;盘后区则由疏松的结缔组织变成纤维软骨盘样组织。

Ultrastructural changes in rabbit disc and bilaminar zone of the TMJ with experimentally induced anterior disk displacement

Objective To investigate the early ultrastructural changes in the rabbit disc and bilaminar zone of the TMJ following surgical induction of ADD. Methods The left joints of 10 New Zealand rabbits were subjected to surgical induction of ADD, the right served as sham control. Four joints from two additional rabbits served as non-operated control. The discs and bilaminar zone were removed after 24 h, 1 week,2 weeks,3 weeks, and 4 weeks and then processed for transmission electron microscopic examination. Results The displaced disc showed the hyperplasia of the chondrocyte- like cells, the disappearance of chondrocyte-like capsular region and the increase of intracytoplasmic filaments. In addition, areas of displaced discs showed loss of the parallel distribution of collagen fibers, neovascularisation and nerve fibers. The bilaminar zone exhibited infantile ehondrocyte-like cells and the compact distribution of collagen fibers in the early stage of ADD,and then became the disc-like tissue. Conclusion The disc lost its ultrastructural characteristics and became connective tissue, and the bilaminar zone became pseudo-disk from loose connective tissue following ADD of the TMJ.