Grubauer G, Feingold K R, Harris R M, Elias P M
Dermatology Service, Veterans Administration Medical Center, San Francisco, CA.
J Lipid Res. 1989 Jan;30(1):89-96.
During terminal differentiation, mammalian epidermal lipids undergo striking changes in both composition and distribution. Phospholipids and neutral lipids are replaced by a mixture of ceramides and neutral lipids organized in intercellular lamellar bilayers. Whether all of these lipids and/or whether specific lipid classes regulate permeability barrier function is not known. When hairless mice were treated with acetone, the degree of barrier perturbation (measured as transepidermal water loss, TEWL) increased linearly with the amount of lipid removed. Moreover, virtually all lipid species appeared to be removed by acetone treatment. In contrast, the nonpolar organic solvent, petroleum ether, while removing greater amounts of lipids, provoked lesser barrier abnormalities. As determined by both quantitative thin-layer chromatography and histochemistry, petroleum ether selectively extracted nonpolar lipids leaving sphingolipids and free sterols in place. In petroleum ether-treated animals, subsequent acetone treatment removed additional sphingolipids and produced a dramatic increase in TEWL. A linear relationship existed for the quantities of sphingolipid removed and degree of barrier disruption in acetone-treated, but not petroleum ether-treated animals. These results support a relationship between the total lipid content of the stratum corneum and barrier function. Secondly, although the results demonstrate the participation of the total lipid mixture in the barrier, removal of nonpolar species alone appears to cause only a modest level of barrier disruption, while removal of sphingolipids and free sterols leads to a more profound level of barrier perturbation.
在终末分化过程中，哺乳动物表皮脂质在组成和分布上都发生了显著变化。磷脂和中性脂质被组织成细胞间层状双分子层的神经酰胺和中性脂质混合物所取代。目前尚不清楚所有这些脂质和/或特定脂质类别是否调节渗透屏障功能。用丙酮处理无毛小鼠时，屏障扰动程度（以经表皮水分流失，即TEWL衡量）随脂质去除量呈线性增加。此外，几乎所有脂质种类似乎都能被丙酮处理去除。相比之下，非极性有机溶剂石油醚虽然能去除更多脂质，但引发的屏障异常较小。通过定量薄层色谱法和组织化学测定，石油醚选择性地提取非极性脂质，使鞘脂和游离固醇保持原位。在经石油醚处理的动物中，随后用丙酮处理会去除额外的鞘脂，并使TEWL显著增加。在丙酮处理而非石油醚处理的动物中，去除的鞘脂量与屏障破坏程度之间存在线性关系。这些结果支持了角质层总脂质含量与屏障功能之间的关系。其次，尽管结果表明总脂质混合物参与了屏障作用，但仅去除非极性脂质似乎只会导致适度水平的屏障破坏，而去除鞘脂和游离固醇则会导致更深层次的屏障扰动。
