正畸力作用下鼠压力侧牙周组织中ATF4和RUNX2表达及意义

Expression of ATF4 and RUNX2 Periodontal Tissues on the Pressure Side during Orthodontic Tooth Movement in Rat

目的:探讨ATF4和RUNX在鼠正畸牙移动过程中的表达变化及其作用。方法:将大鼠按正畸力作用时间分为0、3、6、12、24 h及3、5、7、14 d组,以右侧上颌第一磨牙为实验侧,给予持续正畸力;左侧第一磨牙为对照侧不加力。采用RT-PCR、Western blot法和免疫组织化学法检测ATF4及RUNX2 mRNA和蛋白的表达,HE染色观察其细胞形态。结果:对照侧牙周组织内ATF4和RUNX2 mRNA水平有表达,其蛋白几乎没有表达。实验侧加力后蛋白表达增强并与牙齿移动时间相关。压力区组织在12 h时ATF4和RUNX2表达量最高,24 h后组织中ATF4和RUNX2表达值开始下降;且实验侧ATF4和RUNX2表达量与对照侧比较差异有统计学意义(P<0.05)。结论:压力可以诱导牙周组织中ATF4和RUNX2 mRNA和蛋白的短暂升高,两者在正畸牙移动过程中的牙周组织改建和成骨过程中发挥作用。

Objective：To explore the change and role of transcription factor ATF4 and RUNX2 in periodontal tissues on the pressure side during orthodontic tooth movement in rat.Method：36 SD rats were randomly grouped according to the experimental time of tooth movement ,such as 0,3,6,12,24 h and 3,5,7 d and 14 d. A continuous orthodontic stress was applied on right side maxillary first molar as the experimental group;while the other side maxillary first molar were not subjected to orthodontic stress as the control group. The expression of ATF4,RUNX2 and protein was measured by semi-quantitative RT-PCR,western blot and immunohistochemistry respectively. The morphologic change was observed by HE.Result：There were expressions of ATF4 and RUNX2 mRNA,but almost no expression of the protein level in the control group. While protein expression gradually increased in the experimental group,which was related to the time of tooth movement. in 12 h reached its peak and gradually decreased after 24 h,compared with the control group,the difference was statistically significant（P〈0.05）.Conclusion：Orthodontic stress can induce transient increase of ATF4 and RUNX2 mRNA and protein in periodontal tissue,they play a role in osteogenesis and reconstruction of periodontal tissues during orthodontic tooth movement.