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观察p75神经营养受体(p75 neurotrophin receptor,p75NTR)及Runt相关转录因子2(runt-related transcription factor 2,RUNX2)在SD大鼠下颌第一磨牙成牙发育初期不同发育阶段的表达分布情况,并探讨两者在SD大鼠出生后下颌第一磨牙发育矿化的作用。我们首先制备SD大鼠下颌第一磨牙发育初期标本(E13.5 d,E14.5 d,E15.5 d,E16.5 d,E18.5 d和P0.5 d),免疫组织化学检测p75NTR和RUNX2的表达分布情况。并用表达强度差异较大的天数P0.5 d的大鼠外胚间充质干细胞(ectomesenchymal stem cells,EMSC)进行体外矿化诱导,同时本实验采用蛋白质印迹法检测0 d、7 d、14 d和21 d的p75NTR和RUNX2的表达情况。我们发现p75NTR在蕾状期(E13.5 d)开始表达于成釉器旁边的间质;帽状期(E14.5 d,E15.5 d)广泛表达在内釉上皮、釉结、星网状层、牙乳头、牙囊;钟状期(E16.5 d,E18.5 d,P0.5 d)表达在内釉上皮、釉结、星网状层、中间层、牙乳头,牙囊。RUNX2在蕾状期、帽状初期(E13.5 d,E14.5 d)表达在成釉器下方间质;帽状末期(E15.5 d)达在在内釉上皮、釉结、星网状层、牙乳头、牙囊;钟状期(E16.5 d,E18.5 d,P0.5 d)表达在在内釉上皮、釉结、星网状层、中间层、牙乳头、牙囊;在帽状末期到钟状期(E15.5 d,E16.5 d,E18.5 d)RUNX2与p75NTR的表达范围和强度是相似的,但在钟状分化期(P0.5 d)RUNX2的表达范围类似于p75NTR但强度下降。P0.5 d EMSC蛋白质印迹法结果显示:随着矿化诱导时间的上升,p75NTR和RUNX2的表达均呈上升趋势。这些结果提示我们p75NTR和RUNX2在成牙初期不同天数表达位置及变化,具有时空特异性,可能与牙齿矿化发育相关,矿化诱导后变化趋势趋于一致说明二者在SD大鼠成牙发育初期下颌第一磨牙的发育及矿化中都起到一定的作用,可能存在正相关关系。
To observe the expression and distribution of p75 neurotrophin receptor (p75NTR) and runt-related transcription factor 2 (RUNX2) in different developmental stages of the first molar of SD rat mandibular first molar To explore the role of both in the development of mandibular first molar after SD rats were born. We first prepared SD rat mandibular first molars early development (E13.5 d, E14.5 d, E15.5 d, E16.5 d, E18.5 d and P0.5 d), immunohistochemical detection of p75NTR And RUNX2 expression distribution. And induced by mineralization in vitro with ectomesenchymal stem cells (EMSC) of rats with a significant difference in expression intensity for days P0.5d. At the same time, Western blotting was used to detect the mineralization induced by 0, 7 and 14 d And 21 d of p75NTR and RUNX2 expression. We found that p75NTR began to be expressed in the stroma adjacent to the enamel site at the time of bud formation (E13.5 d); the capsular phase (E14.5 d, E15.5 d) was widely expressed in the enamel epithelium, enamel junction, (E16.5 d, E18.5 d, P0.5 d) expressed in the enamel epithelium, enamel knot, the reticular layer, the middle layer, the dental papilla, the periodontal ligament . RUNX2 was expressed in the stroma below the enamel site at the stage of budding and early capitus (E13.5 d, E14.5 d), while at the end of cap shape (E15.5 d) (E16.5 d, E18.5 d, P0.5 d) expressed in the enamel epithelium, glaze knot, the reticular layer, the middle layer, the tooth papilla, the teeth The expression range and intensity of RUNX2 and p75NTR were similar between the end of cap and the bell (E15.5 d, E16.5 d and E18.5 d) The expression range of RUNX2 is similar to that of p75NTR but its intensity is decreased. P0.5 d EMSC Western blotting results showed that: With the induction of mineralization time, p75NTR and RUNX2 expression showed an upward trend. These results suggest that the expression and location of p75NTR and RUNX2 in different days of early tooth decay have spatial and temporal specificity and may be related to the development of dental mineralization. Initial mandibular first molar development and mineralization have played a certain role, there may be a positive correlation.