Effect of decreased loading on the metabolic activity of the mandibular condylar cartilage in the rat
Effect of decreased loading on the metabolic activity of the mandibular condylar cartilage in the rat
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DOI：
10.1093/ejo/26.1.1
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发表时间：
2004-02-01
影响因子：
2.6
通讯作者：
Sorsa, T
中科院分区：
文献类型：
--
作者：
Pirttiniemi, P;Kantomaa, T;Sorsa, T
本研究的目的是测量减少的颞下颌关节负荷对髁状突软骨的增殖活性和基质产生水平的影响。此外，还检测了关节负荷减少对基质分解蛋白-1(MMP-3)活性的影响，基质分解蛋白-1活性与关节软骨基质破坏状况有关。断奶20天后，试验组喂以软饮食，并定期缩短门牙以防止咬合。对照组被喂以硬质饮食。分别于实验开始后2、6、12、24、48小时测定氚标记胸腺嘧啶核苷掺入活性和放射性标记硫掺入量，实验组在实验开始后6~24小时膝关节软骨对放射性标记硫的摄取量明显低于对照组，12~24小时氚标记胸腺嘧啶核苷掺入活性较低，提示软骨细胞增殖和基质生成减少。实验开始后第9天，实验组各软骨层均可见明显的基质金属蛋白酶-3免疫染色。在对照组中，仅在表层纤维层和侵蚀前沿可见明显的染色。在持续的软饮食和抑制切牙咀嚼后，大鼠下颌突软骨的增殖活性和蛋白多糖合成明显减少。结果表明，足够的负荷对髁状突软骨的生长非常重要，以维持理想的增殖和基质软骨细胞的产生。
The aim of this study was to measure the effect of decreased temporomandibular loading on the proliferative activity and the level of matrix production of the condylar cartilage. The effect of reduced joint loading on the activity of stromelysin-1 (MMP-3), which has been associated with conditions of articular cartilage matrix breakdown, was also examined.Eighty 14-day-old female rats were assigned to two groups. Following weaning at 20 days, the experimental group was fed a soft diet and the incisors were shortened regularly to keep them out of occlusion. The controls were fed a hard diet. The activity of tritiated thymidine incorporation and the incorporation of radiolabelled sulphur were measured 2, 6, 12, 24 and 48 hours after initiation of the experiment.The radiolabelled sulphur intake was significantly lower in the condylar cartilage of the experimental group 6-24 hours after initiation of the experiment, and tritiated thymidine activity was lower after 12-24 hours, indicating lower proliferation and matrix production. The cartilage in the experimental group showed marked immunostaining against MMP-3 in all cartilage layers 9 days after initiation of the experiment. In the control group, the staining was clearly seen only in the superficial fibrous layer and in the erosion front.A marked reduction in proliferative activity and proteoglycan synthesis in mandibular condylar cartilage was found after a continuous soft diet and suppressed incisal mastication in the rat. The results show that sufficient loading is important for condylar cartilage growth, to maintain both ideal proliferation and matrix chondrocyte production.