Teramoto Michitoshi, Kaneko Sawa, Shibata Shunichi, Yanagishita Masaki, Soma Kunimichi
Department of Orofacial Development and Function, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8549, Tokyo, Bunkyo-ku, Japan.
J Bone Miner Metab. 2003;21(5):276-86. doi: 10.1007/s00774-003-0421-y.
To reveal the effect of compressive force on the mandibular condylar cartilage, an appliance was set on 8-week-old Wistar rats to load continuous compressive force. Immunohistochemical and histochemical analyses were performed using toluidine blue, antibodies, and probes for aggrecan, hyaluronan, type II collagen, type X collagen, and 5-bromo-2"-deoxyuridine (BrdU). Histomorphometry and statistical analyses were also performed for aggrecan and BrdU immunostaining. In toluidine blue staining, tissue metachromasia was observed in the transitional zone and the hypertrophic zone of the mandibular condylar cartilage. In histomorphometry and statistical analysis, thickness of the cartilage decreased significantly in all regions in the 3-day experimental group. However, the thickness of the cartilage in the anterior region showed recovery while it decreased continuously in the posterior region. Distributional changes of aggrecan, hyaluronan, type II collagen, and type X collagen in the experimental groups were similar to those for toluidine blue staining. The immunostained area of all these molecules decreased as a result of the decrement of the cartilage area. However, enhanced immunostaining for aggrecan in the proliferative zone was observed only in the 1-day experimental group. BrdU-positive cells, observed in the proliferating zone and the transitional zone, decreased significantly in the experimental group 3 days after force was applied. These results demonstrate that continuous compressive forces on the mandibular condylar cartilage decrease the proliferation of chondrocytes and the amount of extracellular matrices.
为揭示压力对下颌髁突软骨的影响，在8周龄的Wistar大鼠上安装一种装置以施加持续压力。使用甲苯胺蓝、抗体以及针对聚集蛋白聚糖、透明质酸、Ⅱ型胶原、Ⅹ型胶原和5-溴-2'-脱氧尿苷（BrdU）的探针进行免疫组织化学和组织化学分析。还对聚集蛋白聚糖和BrdU免疫染色进行了组织形态计量学和统计分析。在甲苯胺蓝染色中，在下颌髁突软骨的过渡区和肥大区观察到组织异染性。在组织形态计量学和统计分析中，3天实验组所有区域的软骨厚度均显著降低。然而，前部区域的软骨厚度显示出恢复，而后部区域则持续降低。实验组中聚集蛋白聚糖、透明质酸、Ⅱ型胶原和Ⅹ型胶原的分布变化与甲苯胺蓝染色的结果相似。由于软骨面积减小，所有这些分子的免疫染色面积均降低。然而，仅在1天实验组的增殖区观察到聚集蛋白聚糖免疫染色增强。在增殖区和过渡区观察到的BrdU阳性细胞在施加压力3天后的实验组中显著减少。这些结果表明，对下颌髁突软骨施加持续压力会降低软骨细胞的增殖和细胞外基质的量。
