Division of Anatomy, Department of Human Development and Fostering, Meikai University School of Dentistry, Sakado, Saitama, Japan.
Acta Histochem Cytochem. 2011 Feb 26;44(1):17-24. doi: 10.1267/ahc.10033. Epub 2011 Feb 23.
Heat shock protein 27 kDa (Hsp27) functions as a molecular chaperon to prevent apoptosis as well as to contribute to the regulation of cell proliferation and differentiation during development. In the present study, the localization of Hsp27 in the oral epithelium of rats and its expression change during formation of the gingiva with the tooth eruption were examined immunohistochemically to elucidate the roles of Hsp27 in the oral mucosa.In adult rats, Hsp27-immunoreactivity was localized in the prickle and granular layers but absent in the basal and horny layers of the oral epithelium. On the other hand, in the outer and sulcular epithelia of the free gingival, Hsp27-immunoreactivity was detected in the whole layers, while it was not found in the proliferation zone of the junctional epithelium immunoreactive for Ki67. In immature rats on 10th postnatal day, Hsp27-immunoreactivity was intense in the prickle and granular layers of the oral epithelium, but was not detected in its basal layer. In rats at the eruptive phase on 15th postnatal day, Hsp27-immunoreactivity was detected in sites of the basal layer adjacent to where the dental cusps penetrated through the oral epithelium. Although the immunoreactivity for Ki67 was found in the basal layer of the oral epithelium, it was not localized in the Hsp27-immunopositive sites of tooth-penetration in the basal layer. Just after the tooth-eruption on 20th postnatal day, Hsp27-immunoreactivity was not found in the stratified squamous epithelium at the dentogingival junction, whereas it was intense in a single layer of cuboidal epithelial cells attached to the tooth neck. Ki67-positive cells were scattered in the stratified squamous epithelium at the dentogingival junction, whereas no positive cells were found in the portion of a single layer of cuboidal epithelial cells.These findings suggest that the outer and sulcular epithelia of the free gingiva have a relatively slower rate of proliferation than other gingival and oral epithelia, and that Hsp27 might inhibit the proliferation of the basal cells. Such specific phenomenon in the free gingiva occurred immediately after the dental cusps were exposed to the oral cavity.
热休克蛋白 27kDa（Hsp27）作为分子伴侣发挥作用，防止细胞凋亡，并有助于调节发育过程中的细胞增殖和分化。本研究通过免疫组织化学方法检测 Hsp27 在大鼠口腔上皮中的定位及其在牙萌出过程中形成牙龈时的表达变化，以阐明 Hsp27 在口腔黏膜中的作用。在成年大鼠中，Hsp27 免疫反应性定位于棘层和颗粒层，但不存在于口腔上皮的基底层和角质层。另一方面，在游离龈的外表面和沟上皮中，Hsp27 免疫反应性存在于整个上皮层，而在 Ki67 免疫反应性的结合上皮增殖带中未发现。在第 10 天出生后的未成熟大鼠中，Hsp27 免疫反应性在口腔上皮的棘层和颗粒层中强烈，但在基底层中未检测到。在第 15 天萌出阶段的大鼠中，Hsp27 免疫反应性在牙尖穿透口腔上皮的基底层相邻部位被检测到。尽管 Ki67 的免疫反应性存在于口腔上皮的基底层，但它未定位在基底层中与牙穿透相关的 Hsp27 免疫阳性部位。在第 20 天萌出后不久，在牙龈结合部的分层鳞状上皮中未发现 Hsp27 免疫反应性，而在附着在牙颈部的单层立方上皮细胞中则强烈存在。Ki67 阳性细胞散在于牙龈结合部的分层鳞状上皮中，而在单层立方上皮细胞的部分中未发现阳性细胞。这些发现表明，游离龈的外表面和沟上皮的增殖速度比其他牙龈和口腔上皮相对较慢，Hsp27 可能抑制基底层细胞的增殖。这种游离龈的特殊现象发生在牙尖暴露于口腔后立即出现。
