Division of Cardiology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata 951-8514, Japan.
Histochem Cell Biol. 2012 Oct;138(4):583-92. doi: 10.1007/s00418-012-0978-4. Epub 2012 Jun 7.
Recent studies have employed two markers, alpha-smooth muscle actin (α-SMA) and STRO-1, to detect cells with mesenchymal stem cell properties in dental pulp. The present study aimed to explore the expression profile of α-SMA and STRO-1 in intact dental pulp as well as during wound healing in adult dental pulp tissue. Healthy pulps were mechanically exposed and capped with the clinically used materials MTA (ProRoot White MTA) or Ca(OH)₂ to induce a mineralized barrier at the exposed surface. After 7-42 days, the teeth were extracted and processed for immunohistochemical analysis using antibodies against α-SMA, STRO-1 and nestin (a neurogenic cytoskeletal protein expressed in odontoblasts). In normal pulp, α-SMA was detected in vascular smooth muscle cells and pericytes. Double immunofluorescent staining with STRO-1 and α-SMA showed that STRO-1 was localized in vascular smooth muscle cells, pericytes and endothelial cells, in addition to nerve fibers. During the process of dental pulp healing, numerous α-SMA-positive cells emerged at the wound margin at 14 days, and the initially formed mineralized barrier was lined with α-SMA-positive cells similar in appearance to reparative odontoblasts, some of which co-expressed nestin. STRO-1 was abundant in nerve fibers. In the advanced stage of mineralized barrier formation at 42 days, cells lining the barrier were stained with nestin, and no staining of α-SMA was detected in those cells. These observations indicate that α-SMA-positive cells temporarily appear along the wound margin during the earlier phase of mineralized barrier formation and STRO-1 is confined in vascular and neuronal elements.
最近的研究使用了两种标志物，α-平滑肌肌动蛋白（α-SMA）和 STRO-1，来检测牙髓中具有间充质干细胞特性的细胞。本研究旨在探索α-SMA 和 STRO-1 在完整牙髓中的表达谱，以及在成年牙髓组织的伤口愈合过程中的表达。通过机械暴露健康牙髓并用临床上使用的材料 MTA（ProRoot White MTA）或 Ca(OH)₂覆盖暴露表面，以诱导在暴露表面形成矿化屏障。在 7-42 天后，提取牙齿并使用针对α-SMA、STRO-1 和巢蛋白（一种在成牙本质细胞中表达的神经原性细胞骨架蛋白）的抗体进行免疫组织化学分析。在正常牙髓中，α-SMA 存在于血管平滑肌细胞和周细胞中。用 STRO-1 和 α-SMA 进行双重免疫荧光染色显示，STRO-1 定位于血管平滑肌细胞、周细胞和内皮细胞，以及神经纤维中。在牙髓愈合过程中，在第 14 天，在伤口边缘出现了大量的α-SMA 阳性细胞，最初形成的矿化屏障内衬着与修复性成牙本质细胞相似的α-SMA 阳性细胞，其中一些细胞共表达巢蛋白。STRO-1 在神经纤维中丰富。在第 42 天形成矿化屏障的后期阶段，细胞 lining 屏障被巢蛋白染色，而这些细胞中未检测到α-SMA 染色。这些观察结果表明，在矿化屏障形成的早期阶段，α-SMA 阳性细胞暂时出现在伤口边缘，而 STRO-1 局限于血管和神经元成分。
