Thin-layer chromatographic analyses of lipids in different layers of porcine epidermis and oral epithelium.
Frozen cryosections were cut parallel to the surface of porcine skin and palatal, buccal and floor-of-mouth mucosa so as to provide separate samples representing various epithelial layers. The samples were dried, extracted with chloroform:methanol, and the lipids were chromatographed on silica gel plates in various solvent systems. After charring, lipids were quantified with a scanning densitometer. Overall, greater differences in proportions and distributions of lipid components were evident between keratinized and non-keratinized epithelia than between epidermis and keratinized oral epithelium. For epidermis and palate there was an increase in neutral lipids, including ceramides, from the deeper layers to the surface; ceramides were most abundant in surface layers. In buccal epithelium there was a distinct increase in glycosylceramides toward the surface, and in both non-keratinized regions ceramides were present in only very small amounts. The results suggest that although neutral lipids may be associated with a superficial barrier layer in skin and oral mucosa, there are differences in the composition of this barrier between keratinized and non-keratinized epithelia.
Squier
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Dows Institute for Dental Research, College of Dentistry, University of Iowa, Iowa City 52242.
Wertz
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PW
Cox
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D000818:Animals; D002518:Ceramides / Q000737:chemistry; D002855:Chromatography, Thin Layer / Q000379:methods*; D004817:Epidermis / Q000033:anatomy & histology / Q000737:chemistry*; D004848:Epithelium / Q000737:chemistry; D010694:Lactase-Phlorizin Hydrolase / Q000737:chemistry; D008563:Membrane Lipids / Q000737:chemistry*; D009061:Mouth Mucosa / Q000033:anatomy & histology / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry; D013552:Swine
D002518:Ceramides; D008563:Membrane Lipids; D010743:Phospholipids; D010694:Lactase-Phlorizin Hydrolase