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目的: 通过对细胞周期蛋白(CYCLIN) D1 及其与细胞增殖和细胞凋亡在牙齿发生、发育过程中的关系研究,以探讨牙齿发育的机制.方法:选用纯系 S D 大鼠建立牙齿发育模型,采用原位末端标记法( T U N E L 法) 、免疫组织化学染色技术,观察分析纯系 S D 大鼠牙胚发育不同阶段CYCLIN D1 的表达及其与增殖细胞核抗原( P C N A) 和细胞凋亡的关系.结果:在牙胚发育的蕾状期、帽状期、钟状早期的细胞增殖中心处三者表达都很明显.钟状晚期及牙体组织形成后,已分化的成釉细胞、成牙本质细胞中CYCLIN D1 表达阴性, P C N A及凋亡阳性细胞也减少,但牙乳头及星网层细胞中可见二者少量阳性细胞.结论:CYCLIN D1 的表达与 P C N A和细胞凋亡有内在的相互作用关系,三者共同在牙齿发育中发挥重要的调控作用.“,”Aim:To evaluate the mechanism of the tooth development by studying the relation between cyclin D1 and cell proliferation and apoptosis in the tooth development . Methods: The expression of cyclin D1 and the relation among it and PCNA and apoptosis were observed with tooth development model of SD rat and the methods of immunohistochemical staining and Tdt-mediated dUTP nick end labelling (TUNEL) . Results: The expression was significant in the proliferating growth center of the bud ,the cap and earlier bell stage of tooth development. Later, in the differentiated ameloblast and odontoblast the expression of cyclin D1 was negative; the numbers of PCNA- and apoptosis- positive cell were reduced, but some positive cells could be observed in the stellate reticulum cell layer and dental papilla. Conclusions: The expression of cyclin D1 and PCNA and cell apoptosis have their inner interaction. They play an important role in the regulation of the tooth development.