关键词: 皮肤屏障

Abstract:

Objective To evaluate the effects of Prinsepia utilis Royle oil （PURO） on the synthesis of ceramide and expression of acid ceramidase N-acylsphingosine amidohydrolase 1 （ASH1）, and to explore the mechanisms underlying its moisturizing and skin barrier-repairing effects. Methods Keratinocytes from human foreskin tissue were classified into 2 groups to be cultured in keratinocyte-serum free medium （K-SFM） with or without the presence of PURO. Enzyme linked immunosorbent assay （ELISA） was performed to measure the level of ceramide in the culture supernatant of keratinocytes at 0, 3, 8, 24 and 48 hours. The back of nude mice was divided into 4 areas, i.e., test area, matrix area, blank control area and negative control area. Acetone and ether were used to destroy the epidermal barrier in the test, matrix, and blank control areas, then, the former 2 areas were topically treated with emulsions containing 1% PURO and matrix, respectively, and the blank control area remained untreated. The epidermal barrier remained intact and untreated in the negative control area. Noninvasive methods were used to determine transepidermal water loss （TEWL）, epidermal moisture content and skin lipid content in these areas on day 0, 1, 3, and 7. Skin tissue was obtained from these areas on day 0 and 7 followed by an immunohistochemical study for the quantification of ASH1 expression. Results The level of supernatant ceramide increased with time in the PURO-treated keratinocytes, which was significantly higher at 24 hours and 48 hours than at 0 hour （1.3817 ± 0.100 and 1.3737 ± 0.047 vs. 0.7630 ± 0.143, both P < 0.05）. The supernatant ceramide was also elevated in the PURO-treated keratinocytes compared with untreated ker atinocytes at 24 and 48 hours （both P < 0.05）. Noninvasive skin tests showed a gradual decrease in the TEWL, but an increase in the epidermal moisture content and skin lipid content with time in the 3 epidermal barrier-destroyed areas. As far as the test area was concerned, TEWL value was significantly lower on day 3 and 7 than on day 0 （10.85 ± 0.64 and 8.01 ± 0.58 vs. 12.65 ± 0.71, both P < 0.05）, while a significant increment was observed in the skin lipid content on day 3 and 7 compared with day 0 （29.14 ± 0.40 and 31.30 ± 0.88 vs. 27.02 ± 0.65, both P < 0.05）, as well as in the epidermal moisture content on day 1, 3 and 7 compared with day 0 （13.98 ± 0.28, 15.00 ± 0.38 and 15.86 ± 0.18 vs. 11.74 ± 0.62, all P < 0.05）. On day 7, there was a statistical decline in TEWL value, but an elevation in epidermal moisture content, skin lipid content and ASH1 expression in the test area compared with the matrix area and blank control area （all P < 0.05）. Also, the expression of ASH1 was upregulated on day 7 compared with day 0 in the 3 barrier-destroyed areas （all P < 0.05）. Conclusion PURO may exert skin-moisturizing and barrier-repairing effects by enhancing the synthesis of ceramide and expression of acid ceramidase ASH1.

Key words: skin barrier