D'Souza R N, Bachman T, Baumgardner K R, Butler W T, Litz M
Department of Basic Sciences, University of Texas, Houston Health Science Center 77030, USA.
J Dent Res. 1995 Feb;74(2):702-9. doi: 10.1177/00220345950740021301.
During primary dentin formation, differentiating primary odontoblasts secrete an organic matrix, consisting principally of type I collagen and non-collagenous proteins, that is capable of mineralizing at its distal front. In contrast to ameloblasts that form enamel and undergo programmed cell death, primary odontoblasts remain metabolically active in a functional tooth. When dentin is exposed to caries or by operative procedures, and when exposed dentinal tubules are treated with therapeutic dental materials, the original population of odontoblasts is often injured and destroyed. The characteristics of the replacement pool of cells that form reparative dentin and the biologic mechanisms that modulate the formation of this matrix are poorly understood. Based on the hypothesis that events governing primary dentinogenesis are reiterated during dentin repair, the present study was designed to test whether cells that form reparative dentin are odontoblast-like. Cervical cavities were prepared in rat first molars to generate reparative dentin, and animals were killed at various time intervals. In situ hybridization with gene-specific riboprobes for collagen types I and III was used to study de novo synthesis by cells at the injured dentin-pulp interface. Polyclonal antibodies raised against dentin sialoprotein (DSP), a dentin-specific protein that marks the odontoblast phenotype, were used in immunohistochemical experiments. Data from our temporal and spatial analyses indicated that cells forming reparative dentin synthesize type I but not type III collagen and are immunopositive for DSP. Our results suggest that cells that form reparative dentin are odontoblast-like.
在原发性牙本质形成过程中，正在分化的原发性成牙本质细胞分泌一种有机基质，其主要由I型胶原蛋白和非胶原蛋白组成，该基质能够在其远端前沿矿化。与形成釉质并经历程序性细胞死亡的成釉细胞不同，原发性成牙本质细胞在功能牙中保持代谢活跃。当牙本质暴露于龋齿或手术操作时，以及当暴露的牙本质小管用治疗性牙科材料处理时，原始的成牙本质细胞群体常常受到损伤和破坏。形成修复性牙本质的细胞替代池的特征以及调节这种基质形成的生物学机制尚不清楚。基于原发性牙本质形成过程中发生的事件在牙本质修复过程中会重复出现的假设，本研究旨在测试形成修复性牙本质的细胞是否类似成牙本质细胞。在大鼠第一磨牙制备颈部洞以生成修复性牙本质，并在不同时间间隔处死动物。使用针对I型和III型胶原蛋白的基因特异性核糖探针进行原位杂交，以研究受损牙本质-牙髓界面处细胞的从头合成。在免疫组织化学实验中使用针对牙本质涎蛋白（DSP）产生的多克隆抗体，DSP是一种标记成牙本质细胞表型的牙本质特异性蛋白。我们的时空分析数据表明，形成修复性牙本质的细胞合成I型而非III型胶原蛋白，并且对DSP呈免疫阳性。我们的结果表明，形成修复性牙本质的细胞类似成牙本质细胞。
