Cell Death and Cell Proliferation of Myoepithelial cells in Duct-Ligated Submandibular Glands

本研究旨在探讨萎缩大鼠下颌下腺中是否存在肌上皮细胞凋亡和增殖。用金属夹双重结扎右侧下颌下腺的排泄管。对结扎后1-28 d摘除的萎缩右颌下腺进行肌动蛋白和增殖细胞核抗原（PCNA）免疫组化双染、肌动蛋白免疫组化双染、缺口末端标记（TUNEL）凋亡细胞标记和透射电镜观察。少数PCNA-和没有TUNEL阳性的肌上皮细胞被发现在控制下颌下腺从动物没有手术。在实验腺体中，PCNA阳性肌上皮细胞常见于导管结扎后2和3天，然后数量减少。TUNEL阳性的肌上皮细胞出现在2天，也确定了TEM。这些观察结果表明，在大鼠下颌下腺中，肌上皮细胞的凋亡和增殖都发生，特别是在萎缩的早期阶段。

This study was designed to determine whether apoptosis and proliferation of myoepithelial cells occur in atrophic rat submandibular glands. The excretory duct of the right submandibular gland was doubly ligated with the metal clips. The atrophic right submandibular glands removed after 1-28 days of duct-ligation were investigated using immunohistochemical double staining for actin as a marker for myoepithelial cells and proliferating cell nuclear antigen (PCNA), double staining for actin immunohistochemistry, nick-end-labeling (TUNEL) as a marker for apoptotic cells, and transmission electron microscopy (TEM). A few PCNA- and no TUNEL-positive myoepithelial cells were found in the control submandibular glands taken from animals with no operation. In the experimental glands, PCNA-positive myoepithelial cells were common 2 and 3 days after duct ligation and then decreased in number. TUNEL-positive myoepithelial cells appeared at 2 days and were also identified by TEM. These observations suggest that both apoptosis and proliferation of myoepithelial cells occur, especially in the early phase of atrophy, in the rat submandibular gland.