活化蛋白A受体1在成牙本质细胞极化和牙本质形成中的作用

ACVR1 Regulates Odontoblast Polarization and Dentin Formation

目的:研究活化蛋白A受体1(ACVR1)对成牙本质细胞极化及牙本质形成的影响。方法:以Cre-LoxP系统建立牙源性间充质特异性Acvr1基因敲除小鼠模型,取"Osterix-Cre;Acvr1 fx/-基因型小鼠"为实验组,同窝"Osterix-Cre;Acvr1 fx/+基因型小鼠"为对照组。取新生小鼠,通过HE染色观察小鼠下颌切牙的牙本质形成和成牙本质细胞形态;天狼星红染色观察下颌切牙的牙本质胶原排列;免疫荧光染色检测高尔基体(GM130)在下颌切牙成牙本质细胞中的定位。结果:HE染色结果显示,与对照组相比,实验组小鼠下颌切牙有牙本质形成缺陷,牙尖处可见骨样牙本质;从颈环至牙尖,成牙本质细胞形态由多角形变为高柱状,又变为多角形,极性从无到有,再逐渐消失,最终牙尖处部分细胞极性完全丧失。天狼星红染色结果显示实验组小鼠切牙的牙尖处胶原排列紊乱。GM130免疫荧光染色结果显示实验组小鼠切牙的近牙尖处成牙本质细胞中,高尔基体-细胞核相对位置发生变化。结论:Ⅰ型BMP受体ACVR1可维持成牙本质细胞极性并促进牙本质的有序形成,在调控牙本质形成中具有重要作用。

Objectives:to study the effect of ACVR1 on odontoblast polarization and dentin formation.Methods:A dental mesenchymal specific Acvr1 knockout mouse model was established using the Cre-LoxP system.Mice genotyped‘OsterixCre;Acvr1 fx/-’were designated as the experimental group,whereas‘Osterix-Cre;Acvr1 fx/+’were used as the control group.New born mice were harvested.HE staining was used to observe the formation of dentin,and the morphology of odontoblasts in the mandibular incisors.The arrangement of dentin collagenous fibers were observed by Sirius Red stain-ing.Immunofluorescent staining was used to detect the localization of GM130 in the odontoblasts.Results:The results of HE staining showed that the dentin of the mandibular incisors in the experimental group was more disorganized,with os-teodentin formation at the cusp area,compared with the control group.From cervical loop area to cusp area,the morpholo-gy of odontoblasts changed from polygonal to columnar,and then to polygonal,indicating that the polarity of odontoblasts was formed and then compromised,and finally some odontoblasts completely lost their polarity at the cusp area.The re-sults of Sirius Red staining showed that the collagenous fibers in the dentin within the cusp area were more disorganized in the experimental group,compared with the control group.The results of immunofluorescence staining showed that the rela-tive position of Golgi apparatus to the nucleus in the odontoblasts of the experimental group was changed,compared with the control group.Conclusion:BMP typeⅠreceptor ACVR1 can maintain odontoblasts polarity and promote the formation of organized dentin.ACVR1 plays an important role in regulating dentin formation.