Kose discovers that adrenaline reduces epidermal barrier function

 Kose found that adrenaline, one of the hormones secreted by psychological stress, causes disorder of the structure of epidermal tight junctions and inflammation of the epidermis, and reduces the barrier function of the skin, which is responsible for tight junctions. In addition, it was clarified that the inflammation induced by adrenaline can be suppressed by Panax ginseng root extract.

　

The research findings will be applied to future skincare products. In addition, by further elucidating the mechanisms of skin troubles caused by stress and continuing research with a view to well-being that leads to a healthy mind and body, we aim to provide products and services that address skin concerns and improve QOL.

It has been reported that stress reduces the function and resilience of the skin barrier, and disruption of the skin barrier causes symptoms such as dryness, rough skin, and itchiness. Focusing on the relationship between adrenaline, a hormone that is released into the skin, and the tight junctions that are important for the skin barrier, we worked to elucidate the mechanism by which stress lowers the skin barrier function.

A strong skin barrier structure that closes the gaps between adjacent cells in the granular layer of the epidermis is a "tight junction". If a strong tight junction barrier is formed, it is possible to prevent foreign matter from entering from the outside and moisture from inside the skin to evaporate.

Therefore, adrenaline was added to a three-dimensional epidermis model that experimentally reproduced human epidermis, and its effects on tight junctions and skin barrier function were verified. As a result, the addition of adrenaline obscured the images of tight junctions, suggesting that cell-to-cell adhesion was disturbed. Furthermore, in addition to a decrease in the electrical resistance value, which represents the barrier function of the epidermal model, a decrease in the gene expression level of occludin, a major constituent protein of tight junctions, was also observed. From this, it was clarified that adrenaline reduces the skin barrier function through poor formation of tight junctions.

Since it is generally known that inflammation lowers the tight junction barrier, we verified the effect of adrenaline on epidermal inflammation. As a result, an increase in inflammatory factor IL-6 was observed in epidermal cells to which adrenaline was added. This suggests that adrenaline induces inflammation in the epidermis, further lowering the tight junction barrier.

Panax ginseng root extract has long been used as an effective herbal medicine for recovery from fatigue. We analyzed the gene expression levels of inflammatory factor IL-6 in epidermal cells added with adrenaline. As a result, it was found that the expression level of IL-6 was lower in epidermal cells to which Panax Ginseng Root Extract was added than in cells to which it was not added, indicating that the extract has the effect of suppressing adrenaline-induced inflammation.

From the above, it has been shown that inflammation caused by adrenaline and a decrease in the barrier of epidermal tight junctions may be part of the cause of skin problems associated with psychological stress. Furthermore, since the Panax ginseng root extract suppresses inflammation caused by adrenaline, it was considered to be a useful material for preventing skin troubles caused by stress.