大鼠实验性牙移动牙周组织Ⅰ型胶原的表达变化

Effect of Orthodontic Force on Collagen Ⅰ Expression in Periodontium of Rat

目的研究正畸力作用下大鼠牙周膜中Ⅰ型胶原的表达变化，探讨正畸牙移动过程中牙周组织的改建机理。方法将56只SD大鼠一侧上颌第一磨牙和前牙间用结扎丝拴结正畸用Ni-Ti螺旋弹簧，按正畸力大小分成施加50g正畸力的轻力组28只、施加150g正畸力的重力组28只。对侧未做处理的磨牙作为对照组。分别于加力后3、6、12、24h和3、7、14d分7次处死，每次每组处死4只。采用免疫组织化学染色技术分别观察大鼠牙周膜中Ⅰ型胶原在机械力刺激下的免疫阳性表达变化及相互关系。结果加力侧与对照侧牵张区之间的染色强度差异有统计学意义（P〈0．05），轻力组与重力组压缩区与牵张区染色强度差异有统计学意义（P〈0．05），牵张区染色强度明显高于压缩区。牵张区1～3d开始强表达，一直持续到14d；压缩区1d后开始表达减弱，7d后开始回升。另外发现50～150g正畸力对大鼠牙周组织无明显破坏。结论机械力作用下，大鼠牙周膜Ⅰ型胶原代谢发生变化，牵张区表达增强，压缩区表达减弱；机械力作用下Ⅰ型胶原表达变化与时间密切相关；50～150g的机械力范围是实验鼠正畸用力的安全范围。

Objective The purpose of the present study was to explore the rebuilding mechanisms during the orthodontic tooth movement by oberserving the variation of collagen Ⅰ expression in periodontium challerged by mechanical stimulation. Methods The involved male SD rats were divided into light force group and heavy force group according to the orthodontic force magnitude. The variation of the expression of collagen Ⅰ in periodontium was observed immunohisteehemieally and the variation of mechanical stimulation was studied. Results Under the application of mechanical force the experimental teeth showed significant increase of collagen Ⅰ in the tension zones as opposed to the pressure zones, the expression of collagen Ⅰ increased on dl and sustained the high level of expression on d14 in the tension zones, while it decreased from dl and turned back from d7 in the pressure zones. The mechanical forees of 50- 150 g had no significant destructive effect on the rat periodontium. Conclusion Under the application of mechanical force, the expression of collagen Ⅰ in periodontium changed signifieandy. The experimental teeth showed a significant increase of collagen Ⅰ in the tension zones as opposed to the pressure zones. Under the application of meebanical foree, the expression of collagen Ⅰ in periodontium manifested a time-dependenee tendency. The force of 50 - 150 g is safe in orthodonties.