1 research outputs found
Immunohistochemical study of the apoptosis process in epidermal epithelial cells of rats under a physiological condition
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 mitochondrialindependent
pathway, and that a mitochondrialdependent
pathway finally accelerated under physiological conditions