Division of Biological Resources and Development, Analysis Research Center for Experimental Sciences, Saga University, Nabeshima, Saga, Japan.
Arch Gerontol Geriatr. 2010 Jul-Aug;51(1):e11-5. doi: 10.1016/j.archger.2009.07.005. Epub 2009 Aug 14.
To ascertain whether laboratory rats represent an adequate animal model for aging oral cavity research, this study focused on the morphology of the mandibular condyle. Aging changes of cartilaginous conformation and shape of the mandibular condyles were analyzed in female F344/N rats. In the condylar cartilage, articular, proliferative cell and hypertrophic cell layers were observed in 1-month-old (M) rat, whereas flattened cell layer was notable at 2M. A mature cell layer was observed in the condylar cartilage of rats at 7.7 M and over. Deranged cartilaginous layers and thinning articular layer were observed in 30.9 M rat. The sagittal length of the condyle decreased, whereas the frontal one increased with aging and/or age. There were three phases in the transition patterns of the size of the condyle, which seemed to correspond to the respective growing, aging and senescence phases in the rat. The results suggested that degenerative change of condylar cartilage in rat was similar to that in human, whereas change of the shape of the condyle was different between rat and human, caused by a different pattern of mastication.
为了确定实验大鼠是否能够作为研究口腔衰老的合适动物模型，本研究聚焦于下颌骨髁突的形态。对雌性 F344/N 大鼠的髁突软骨的形态结构变化进行了研究。在 1 月龄（M）大鼠的髁突软骨中观察到关节面、增殖细胞和肥大细胞层，而在 2M 时可见扁平细胞层。在 7.7M 及以上的大鼠的髁突软骨中观察到成熟的细胞层。在 30.9M 大鼠中可见软骨层紊乱和关节层变薄。随着年龄的增长和/或衰老，髁突的矢状长度减小，而额状长度增加。髁突大小的变化存在三个阶段，这似乎与大鼠的生长、衰老和老年化阶段相对应。研究结果表明，大鼠髁突软骨的退行性变化与人相似，而髁突形状的变化则不同于人和大鼠，这是由于咀嚼模式的不同所致。
