p21^(Waf1/Cip1)蛋白在侧腭突MEE/MES消失过程中的表达及意义

Expression and significance of p21^(Waf1/Cip1) during the disappearance of MEE/MES in lateral palatine process

目的:探讨p21 Waf1/Cip1(p21)蛋白与调控p21的相关蛋白Jag1、Jag2、Notch1在正常胎鼠和腭裂模型侧腭突胚胎上皮,特别是胚胎腭中线上皮细胞、胚胎腭中线上皮带中的表达及变化,初步研究p21蛋白在胚胎腭中线上皮细胞、胚胎腭中线上皮带消失过程中的作用。方法:实验组为全反式维A酸(all-trans retinoic acid,at RA)诱导建立的C57BL/6J胎鼠腭裂模型,对照组用同等剂量玉米油喂养孕鼠。在鼠孕期第13.5天(gestation day,GD13.5)、GD14.5、GD15.5、GD16.5解剖取得胎鼠腭突,吖啶橙染色观察腭突形态,免疫组织化学染色检测p21与Jag1、Jag2、Notch1在胎鼠侧腭突上皮的表达。结果:实验组Jag1、Jag2、Notch1、p21在各个时间点均呈阴性表达。在GD14.5、GD15.5,对照组Jag1、Jag2、Notch1、p21在胚胎腭中线上皮带细胞内均有阳性表达。在GD15.5,对照组胚胎腭中线上皮带消失,腭突基本融合;实验组则胚胎腭中线上皮细胞未消退,形成腭裂。在GD16.5,Jag1、Jag2、Notch1在侧腭突所有被覆上皮仍有阳性表达,p21仅在鼻腔侧有微弱阳性表达。结论:在胎鼠侧腭突发育过程中,存在Jag1、Jag2、Notch1、p21特定时空的差异表达。结合前期试验,提示p21参与侧腭突上皮的凋亡与分化,尤其参与了ΔNp63在胚胎腭中线上皮细胞、胚胎腭中线上皮带消失过程中的作用。

PURPOSE： To investigate the expression of p21Waf1/Cip1（p21） related protein Notch1, Jag1, Jag2 and p21 in lateral palatine process of normal embryonic mouse and embryonic mouse with cleft palate, especially in MEE/MES, and explore the significance of p21 during the disappearance of MEE/MES. METHODS： Embryonic mouse with cleft palate was induced by all-trans retinoic acid（at RA）, the control group was given the equivalent volume of corn oil. The embryonic palates on the 13.5 gestation day（GD13.5）, GD14.5, GD15.5 and GD16.5 were obtained. The specimens were observed under acridine orange staining. The expression of p21, Notch1, Jag1 and Jag2 was detected by immunehistochemistry. RESULTS： The expression of p21, Notch1, Jag1 and Jag2 in the experimental group was negative in MEE/MES cells on each gestation day, while it was positive in the control group on GD14.5 and GD15.5. On GD15.5,palate was fused with the disappearance of MES in the control group, whereas MEE / MES did not completely subside in the experimental group. On GD16.5, palate was fused completely in the control group while palate was not fuse in the experimental group, leading to cleft palate. The expression of Jag1, Jag2 and Notch1 was still positive in all epithelium of lateral palatine process. However, p21 only appeared in the nasal side. Palate fused completely in control group while palate was not fused in the experimental group, leading to cleft palate. CONCLUSIONS： This study showed that the expression of p21, Notch1, Jag1 and Jag2 was differential in specific time and space in the epithelium of embryonic mouse lateral palatine process, and p21 was involved in apoptosis and differentiation in lateral palatine process epithelia,especially in the process of ΔNp63 regulating the disappearance of MEE/MES.