Imokawa G, Akasaki S, Hattori M, Yoshizuka N
J Invest Dermatol. 1986 Dec;87(6):758-61. doi: 10.1111/1523-1747.ep12456950.
Selective removal of stratum corneum lipids following applications of acetone/ether to the human forearm for extremely prolonged periods of 5-20 min induced an enduring (more than 4 days), chapped and scaly appearance of the skin which was accompanied by a significant decrease in the water-holding properties of the stratum corneum. In order to further elucidate the significance of lipids in the water-holding properties, lipids, which were extracted as sebaceous-rich lipids (SL) for the first 10-min acetone/ether treatment and as stratum corneum lipids (SCL) for the additional 30-min treatment, were topically applied daily on lipid-depleted forearm skin which had been pretreated with acetone/ether for 40 min. Two daily applications of the SCL which were solubilized in squalane containing 1% alpha-monomethyl heptadecyl glyceryl ether (GE) caused a significant increase of conductance, accompanied by a marked improvement in the level of scaling as compared with nontreatment or GE/squalane base, whereas the SL in the GE/squalane base did not exhibit any significant recovery in either conductance value or scaling. To clarify which components of the SCL are primarily responsible for the observed recovery of the water-holding properties, chromatographically separated fractions of the SCL were also topically applied in the same manner for 2 successive days. Out of the following separated fractions: cholesterol, cholesterol ester, free fatty acid, glycolipids, and ceramide, 2 daily topical applications of ceramide fraction induced a significant and the highest increase in the conductance value as compared with GE/squalane base. Furthermore, glycolipids and cholesterol fractions also exhibited a significant recovery when compared with no application at all. In contrast, free fatty acid and cholesterol ester fractions did not indicate any significant increase in the conductance value. These findings strengthen the hypothesis that structural lipids present in the intercellular spaces of the stratum corneum, especially ceramide, play a critical role in the water-holding properties of the stratum corneum.
在人前臂上极长时间（5 - 20分钟）涂抹丙酮/乙醚后，选择性去除角质层脂质会导致皮肤出现持久（超过4天）的干裂和鳞屑外观，同时角质层的持水性能显著下降。为了进一步阐明脂质在持水性能中的重要性，在前10分钟丙酮/乙醚处理中提取为富含皮脂的脂质（SL），在额外30分钟处理中提取为角质层脂质（SCL）的脂质，每天局部应用于已用丙酮/乙醚预处理40分钟的脂质耗尽的前臂皮肤。每天两次涂抹溶解在含有1%α - 单甲基十七烷基甘油醚（GE）的角鲨烷中的SCL，与未处理或GE/角鲨烷基质相比，导致电导率显著增加，同时鳞屑水平有明显改善，而GE/角鲨烷基质中的SL在电导率值或鳞屑方面均未表现出任何显著恢复。为了阐明SCL的哪些成分主要负责观察到的持水性能恢复，SCL经色谱分离的组分也以相同方式连续两天局部应用。在以下分离组分中：胆固醇、胆固醇酯、游离脂肪酸、糖脂和神经酰胺，与GE/角鲨烷基质相比，每天两次局部应用神经酰胺组分导致电导率值显著且最高增加。此外，与未应用相比，糖脂和胆固醇组分也表现出显著恢复。相比之下，游离脂肪酸和胆固醇酯组分在电导率值上未显示任何显著增加。这些发现强化了这样一种假设，即角质层细胞间空间中存在的结构脂质，尤其是神经酰胺，在角质层的持水性能中起关键作用。
