Localization of Heat Shock Protein 27 (Hsp27) in the Rat Gingiva and its Changes with Tooth Eruption

Abstract

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.

Localization of Hsp27 in the Rat Submandibular Gland Following the Application of Various Surgical Treatments

“…Negative control sections were reacted with PBS instead of the primary antibody, stained in the same manner, and were confirmed to have no non-specific immunoreactions. The application and specificity of these antibodies to rat tissue have already been confirmed in our previous studies [ 2 , 3 , 24 ].…”

Butyric acid retention in gingival tissue induces oxidative stress in jugular blood mitochondria

“…This would insinuate that high BA amounts could accumulate in the gingival tissues (Kurita-Ochiai and Ochiai 2010; Maslowski et al 2009). Gingival tissues are composed of stratified squamous epithelial cells which have keratinized regions that exhibit low permeability (Sasaki et al 2011;Squier 1991). We suspect that due to the low permeability found within the gingival tissues, this would consequentially result into prolonged BA retention and, subsequently, allow high BA levels to accumulate.…”

Differential expression of heat shock protein 27 in oral epithelial dysplasias and squamous cell carcinoma

“…Immunoreactivity in the basal layer was confined to oral gingival and sulcular epithelium, but no immunoreactivity was found in the horny layer. [ 27 ] As we know, sulcular epithelium is nonkeratinized. Further studies are necessary to know whether there is differential expression of HSP27 in different regions of oral cavity and whether this is related to keratinization.…”