title: Immunohistochemical study of the apoptosis process in epidermal epithelial cells of rats under a physiological condition.
abstract: Epidermal homeostasis is maintained by both epithelial proliferation in the stratum basale (SB) and the apoptosis of epithelial cells under physiological conditions. In this study, the induction and regulation mechanisms of epidermal apoptosis were immunohistochemically investigated in the epidermis from Wistar rat's palm and foot pad by using several apoptotic related proteins under a physiological condition. The results showed that Fas and Fas-L were expressed in cellular membranes of the stratum spinosum (SS), whereas TNF-R1 did not show any membranous expression in any epidermal layers. TNF-α was not observed in the epidermis. Caspase-10, cleaved caspase-3 and DNase-1 were found in the epithelial cytoplasms from the SS to stratum granulosum (SG), whereas caspase-8 was not detected in the epidermis. XIAP and Bak were found in the cytoplasm from the SS to SG, and the intensity of Bak-positivity was stronger in the SG than the SS, whereas Bid, Apaf-1 and cleaved caspase-9 were restricted in the SG. Homogenous cytoplasmic immunoreactivity of Bcl-2 was found in the SB and the intensity was gradually decreased from the SB to the SG. The granular-cytoplasmic immunopositivity of cytochrome C gradually altered into homogenous cytoplasmic expression in the upper half of the SG. Single-stranded DNA was rarely detected in the upper portion of the SG. These results suggest that epidermal apoptosis is induced by the interaction between Fas and Fas-L and the activation of caspase-10, and might initially proceed through a mitochondrial-independent pathway, and that a mitochondrial-dependent pathway finally accelerated under physiological conditions.
authors.affiliation: Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, Japan.
authors.forename: K G S
authors.initials: KG
authors.lastname: Udayanga
authors.forename: H
authors.initials: H
authors.lastname: Miyata
authors.forename: Y
authors.initials: Y
authors.lastname: Yokoo
authors.forename: W-M
authors.initials: WM
authors.lastname: Qi
authors.forename: E
authors.initials: E
authors.lastname: Takahara
authors.forename: Y
authors.initials: Y
authors.lastname: Mantani
authors.forename: T
authors.initials: T
authors.lastname: Yokoyama
authors.forename: N
authors.initials: N
authors.lastname: Hoshi
authors.forename: H
authors.initials: H
authors.lastname: Kitagawa
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D053477:Apoptotic Protease-Activating Factor 1 / Q000378:metabolism; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000502:physiology*; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology; D053222:Fas Ligand Protein / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D019014:fas Receptor / Q000378:metabolism
chemical_list: C506594:Apaf1 protein, rat; D053477:Apoptotic Protease-Activating Factor 1; D051023:BH3 Interacting Domain Death Agonist Protein; C494827:Bax protein, mouse; C494816:Bid protein, rat; D004277:DNA, Single-Stranded; D053222:Fas Ligand Protein; C491898:Fas protein, rat; C505662:Faslg protein, rat; D047888:Receptors, Tumor Necrosis Factor, Type I; C506237:Tnfrsf1a protein, rat; D051636:X-Linked Inhibitor of Apoptosis Protein; D051028:bcl-2-Associated X Protein; D019014:fas Receptor; D045304:Cytochromes c; D003850:Deoxyribonuclease I; D020169:Caspases