Fan Xin-Ping, Zhao Yun-Feng, Liu Wei-Ping, Zhao Xiao-Qin
Department of Stomatology, Tongji Hospital, Tongji University, Shanghai 200065, China.
Sichuan Da Xue Xue Bao Yi Xue Ban. 2005 Nov;36(6):843-6.
To investigate the altered expression level of type III collagen mRNA in the periodontal ligament of rat molar in response to changes in occlusal force.
A model of the rat experimental occlusal trauma was established, in which the occlusal surface on the upper first molar of (250+/-20) g male SD rats was approximately 1 mm elevated unilaterally. Another model was establishde, in which the upper first molar was extracted to remove occlusal force against the lower first molar. The rats were perfusion-fixed at 12 h and on the 3rd, 7th, 14th and 30th day after treatment. The prepared sagittal sections were processed to study the expression of type III collagen mRNA in rat periondontal ligament by in situ hynbridization.
Following the bite-raising,the number and the desity of the positive cells of type III collagen mRNA in the periodontal ligament of the lower first molar increased gradually. The expression of type III collagen mRNA was the strongest on the 7th day (124.03 +/- 14.82). Comparde to the normal rats,the expression level of type III collagen mRNA in the periodontal ligament of the lower first molar significantly decreased on the 14th day (63.07 +/- 5.69). When occlusal force was removed the expression level of type III collagen mRNA in the periodontal ligament of the lower first molar showed a rapid decrease. Subsequently, a gradual increase was recognized. Compared to the normal animal,a more significant increase (154.39 +/- 17.61) was detected on the 7th day after occlusal force was removed.
The results suggest that type III collagen may play important roles in the process of periodontium remodeling against different occlusal force.
研究大鼠磨牙牙周膜中III型胶原mRNA表达水平随咬合力变化的情况。
建立大鼠实验性咬合创伤模型，将体重（250±20）g雄性SD大鼠的上颌第一磨牙咬合面单侧抬高约1mm。另建立一个模型，拔除上颌第一磨牙以消除对下颌第一磨牙的咬合力。在处理后12小时、第3天、第7天、第14天和第30天对大鼠进行灌注固定。制备矢状切片，通过原位杂交研究大鼠牙周膜中III型胶原mRNA的表达。
抬高咬合面后，下颌第一磨牙牙周膜中III型胶原mRNA阳性细胞的数量和密度逐渐增加。III型胶原mRNA的表达在第7天最强（124.03±14.82）。与正常大鼠相比，第14天下颌第一磨牙牙周膜中III型胶原mRNA的表达水平显著降低（63.07±5.69）。去除咬合力后，下颌第一磨牙牙周膜中III型胶原mRNA的表达水平迅速下降。随后，出现逐渐增加。与正常动物相比，去除咬合力后第7天检测到更显著的增加（154.39±17.61）。
结果表明III型胶原可能在牙周组织针对不同咬合力的重塑过程中发挥重要作用。
