Plantar epidermis of the guinea pig and characteristics of the stratum corneum.
The guinea pig plantar epidermis was examined by light-microscopical histochemical methods and by transmission electron microscopy. Autolysis of cell structure was much less complete in guinea pig plantar horny layer than in the back, and stainable cytoplasm was retained in keratinized cells but organelles were lost except for some degraded ultrastructural remnants. By light microscopy the whole thickness of the horny layer showed bound phospholipid and bound cysteine, and there was a weak cystine reaction at the peripheries of the keratinized cells. In ultrastructure the keratohyalin contained slightly larger subparticles than in the back skin. The horny layer was not divisible into basal, intermediate and superficial regions as in hairy skin. The stratum lucidum of light microscopy was not defined in electron micrographs. Osmium-stained cytoplasmic material was retained in horny cells about to be desquamated, in contrast to the empty appearance of these cells in hairy skin. Epidermal cells in plantar skin have ultrastructural cytoplasmic processes which are longer than they are broad. In the horny layer these interdigitate with those of neighbouring cells and are held together by lateral demonsomal junctions. Probably this gives mechanical strength against shearing forces experienced by the plantar horny layer.
D000818:Animals; D001329:Autolysis; D003545:Cysteine / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D005528:Foot; D006168:Guinea Pigs; D006651:Histocytochemistry; D010743:Phospholipids / Q000378:metabolism; D012867:Skin / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure*
D010743:Phospholipids; D003545:Cysteine