Project description:Dietary collagen hydrolysate has been conjectured to improve skin barrier function. To investigate the effect of long-term collagen hydrolysate administration on the skin, we evaluated stratum corneum water content and skin elasticity in intrinsic aged mice. Female 9-week-old hairless mice were fed a control diet, or a collagen hydrolysate-containing diet, for 12 weeks. The stratum corneum water content and skin elasticity were sequentially decreased by chronological aging in control mice. Intake of collagen hydrolysate significantly suppressed such changes. Moreover, we comprehensively analyzed gene expression in the skin of mouse, which had been administered collagen hydrolysate, using DNA microarray. Twelve weeks after start of collagen intake, no significant differences appeared in gene expression profile compared to that of control group. However, 12 weeks after administration, 135 genes were up-regulated and 448 genes were down-regulated in collagen group compared to control group. It is indicate that gene changes preceded changes of barrier function and elasticity. We focused on several genes correlated with functional changes in the skin. Gene Ontology terms, especially related to epidermal cell development, were signi?cantly enriched in up-regulated genes. These skin function-related genes had properties that facilitate epidermal production and differentiation and suppress dermal degradation. Thus, dietary collagen hydrolysate induced positive gene changes. In conclusion, our results suggest that alteration of gene expression at early stages after collagen administration affect skin barrier function and mechanical properties. Long-term oral intake of collagen hydrolysate improves skin dysfunction by regulating genes related to production and maintenance of the skin tissue. Nine-week-old female Hos:HR-1 hairless mice (Japan SLC Inc., Shizuoka, Japan) were used in this study. All mice were housed in plastic cages (4 mice/cage) in a temperature and humidity controlled room (24 ± 1°C and 50 ± 10% humidity) under a 12 hour light-dark cycle. Mice were given an AIN-93G (Oriental Yeast Co., Ltd., Tokyo, Japan) diet and water. The present study was approved by the Animal Committee of Meiji Seika Kaisha Ltd., Food & Health R&D Laboratories, with the animals receiving care under the Guiding Principles for the Care and Use of Laboratory Animals of this committee. All surgery was performed under isoflurane anesthesia, and all efforts were made to minimize suffering. Sixteen female mice were randomly divided into two groups (n = 8 /group) according to their body weight, stratum corneum water content, and skin elasticity. During the experimental period for 12 weeks, the control group was fed a control diet (AIN-93G) and the collagen group was fed a collagen diet consisting of a mixture of 2.0 g of collagen hydrolysate and 100 g of the control diet. Fish scale collagen hydrolysate was purchased from Nitta Gelatin Inc. (Osaka, Japan). This amount of collagen hydrolysate is approximately equivalent to oral ingestion of 2.0 g collagen hydrolysate/kg body weight/day.

Project description:Renin-angiotensin system regulates cell proliferation, differentiation, apoptosis and tissue remodeling in skin. Previouly, we reported that angiotensin-converting enzyme (ACE) expression and angiotensin II level were enhanced by repeated UVB-irradiation of hairless mice skin, and ACE inhibitor enalapril maleate accelerated recovery of UVB-induced wrinkle. In present study, we analyzed gene expression with DNA microarray and protein distribution with immunofluorecence method to clarify the process of wrinkle repairing with enalapril maleate in UVB-irradiated hairless mouse. In microarray analysis, we detected up-regulation of various extracullular matrix (ECM) genes and ECM related genes. In immunofluorescence, we confirm that type 1 collagen, fibrillin1, elastin, and dystroglycan 1 were decreased by repeated UVB-irradiation and the distribution of these components were improved by enalapril maleate treatment. In addition, ADAMTS2 and MMP-14, these were perticipate in ECM structure formation and degradation, were increased in enalapril maleate-treated mouse skin. While the functions of these molecules in skin is not clear yet, it is suggested that these molecules participate in improvement of wrinkles induced by UVB-irradiation. Male hairless mice of the SKH-1 strain were purchased from Charles River Laboratories Japan, Inc. (Tokyo, Japan). These animals were approximately 6 weeks old at the start of the experiment. They were fed a commercial diet (CRF-1, Oriental Yeast Co., Ltd, Tokyo, Japan) ad libitum and allowed free access to water. The dorsal region of the mouse was repeatedly irradiated with UVB for 10 weeks. Enalapril maleate treatment was started at 1 week after 10-week irradiation. One hundred microliters of 1% w/v enalapril maleate dissolved in 30 vol % ethanol solution or 30 vol % ethanol (control) was applied 5 times a week for 2 consecutive weeks to the whole dorsal skin of each of the mice. All experimental procedures using mice were approved by the Animal Experiment Committee of Tokyo University of Agriculture and Technology (approval number 24-82). The dosal region of the mouse was repeatedly irradiated with UVB for 10 weeks. Enalapril maleate treatment was started at 1 week after 10-week irradiation. One hundred microliters of 1% w/v enalapril maleate dissolved in 30 vol % ethanol solution or 30 vol % ethanol (control) was applied 5 times a week for 2 or 6 consecutive weeks to the whole dorsal skin of each of the mice. Each of the experimental groups comprised 6 mice. After 2- or 6-week drug treatment, skin samples were collected for microarray analysis.

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Mus musculus

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