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

本研究旨在确定萎缩大鼠颌下腺肌上皮细胞是否发生凋亡和增殖。右颌下腺排泄管用金属夹双重结扎。采用肌动蛋白免疫组化双染色（肌动蛋白是肌上皮细胞和增殖细胞核抗原（PCNA）的标记物）、肌动蛋白免疫组化双染色、镍端标记（TUNEL）是凋亡细胞的标记物)和透射电子显微镜（TEM）对1-28 d后切除的萎缩右侧颌下腺进行研究。未手术动物的对照下颌骨腺中有少量PCNA阳性肌上皮细胞，未见tunel阳性肌上皮细胞。在实验腺体中，pcna阳性的肌上皮细胞在导管结扎后的第2天和第3天出现，随后数量减少。第2天出现tunel阳性肌上皮细胞，并通过透射电镜进行鉴定。这些观察结果表明，在大鼠颌下腺中，肌上皮细胞的凋亡和增殖同时发生，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.