Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, Yongin-si, Gyeonggi-do, Republic of Korea.
Nutr Res. 2012 Dec;32(12):956-64. doi: 10.1016/j.nutres.2012.09.006. Epub 2012 Oct 23.
We have previously reported that dietary sericin improves epidermal dryness with the increased total Ceramide (Cer) in NC/Nga mice, an animal model of atopic dermatitis (AD). In this study, we hypothesized that the increased level of total Cer induced by dietary sericin would be related to the altered metabolism of glucosylceramide (GlcCer) and sphingomyelin (SM), major precursors of Cer generation. NC/Nga mice were fed a control diet (group CA: atopic control) or diets with 1% silk protein, either sericin (group S) or fibroin (group F) for 10 weeks. In the epidermis of group CA, total Cer (including Cer1, 2, 3/4 and 6) and all GlcCer species were reduced; these levels in group S were increased to levels similar to or higher than in the normal control group of BALB/c mice (group C). In addition, the protein expressions, but not mRNA expressions, of GlcCer synthase, β-glucocerebrosidase, and acidic sphingomyelinase, enzymes for GlcCer synthesis, GlcCer and SM hydrolysis, respectively, were highly increased in group S. The epidermal levels of total Cer (including Cer2, 3/4, and 6) and all GlcCer species and of these enzyme proteins in group F were lower than in group S. Notably, alterations in total SM, SM1, SM3, and SM synthase 1, which were increased in group CA, were not significant between groups S and F. Cer5 and SM2 were not altered among groups. Dietary sericin enhanced the epidermal levels of all GlcCer and most Cer species with up-regulating protein expressions of GlcCer synthase, β-glucocerebrosidase, and acidic sphingomyelinase.
我们之前报道过，食用丝胶可通过增加 NC/Nga 小鼠（特应性皮炎 AD 动物模型）表皮中的总神经酰胺（Cer）来改善皮肤干燥。在这项研究中，我们假设丝胶诱导的总 Cer 水平升高与葡糖脑苷脂（GlcCer）和神经鞘磷脂（SM）代谢的改变有关，GlcCer 和 SM 是 Cer 生成的主要前体。NC/Nga 小鼠分别喂食对照饮食（CA 组：特应性对照）或含 1%丝蛋白的饮食，丝胶（S 组）或丝素（F 组）。在 CA 组的表皮中，总 Cer（包括 Cer1、2、3/4 和 6）和所有 GlcCer 种类均减少；S 组中的这些水平增加到类似于或高于 BALB/c 小鼠（C 组）的正常对照组水平。此外，GlcCer 合成酶、β-葡萄糖脑苷脂酶和酸性神经鞘磷脂酶的蛋白表达（而非 mRNA 表达）在 S 组中高度增加，这些酶分别负责 GlcCer 合成、GlcCer 和 SM 水解。F 组的总 Cer（包括 Cer2、3/4 和 6）和所有 GlcCer 种类以及这些酶蛋白的表皮水平均低于 S 组。值得注意的是，在 CA 组中增加的总 SM、SM1、SM3 和 SM 合酶 1 在 S 组和 F 组之间没有显著差异。Cer5 和 SM2 在各组之间没有变化。饮食丝胶通过上调 GlcCer 合成酶、β-葡萄糖脑苷脂酶和酸性神经鞘磷脂酶的蛋白表达，增强了表皮中所有 GlcCer 和大多数 Cer 种类的水平。
