薬理と治療

Abstract

Background　Langerhans cells, which are scattered in the epidermal squamous cell layer as dendritic cells, are suggested to play an important role for alleviation or healing of inflammation through their regulatory function for the dermal barrier. Especially, in atopic dermatitis, the deterioration of the dermal barrier function is suggested to be a serious factor, and the relationship between the function of Langerhans cells as a reinforcement of dermal barrier and atopic dermatitis is very interested. However, there has been neither any useful product which can induce remission of atopic dermatitis, nor any product which is focused on the epidermal Langerhans cells developed yet. Objective　To study the effects of PS, which is a unique complex of amino acids developed by us and has many good results for several dermatitis such as atopic dermatitis, on the epidermal Langerhans cells. Methods　One ％ hydrocortisone（HC）in 10 μL ethanol was applied twice daily for 5 days on the inner surface of the right ears of BALB/c mice（steroid-treatment）. Non-steroid- treatment （control）group of the mice was applied 10 μL ethanol. It was confirmed that the number of epidermal Langerhans cells（shown as MHC Class Ⅱ-positive cells in the epidermis area）is decreased in the murine ears of steroid-treatment groups as reported previously（Meingassner JG, et al. Br J Dermatol 2003; 149: 853-7）. In order to study the effects of PS, 10 μL of PS was applied once a day for 3 days, 9 days, 16 days, and 23 days on the inner surface of the murine right ears of steroid-treatment group. In the control group, 10 μL of saline was administered instead of PS. The murine ears in each group were gathered and their paraffin-embed samples were prepared. The number of MHC Class Ⅱ-positive cells in the epidermis area within 2000 μm from the top in the inner ear of each sample was counted as that of epidermal Langerhans cells. Also, the ear thickness and the square measure of the epidermis area within 2000 μm from the top in the inner ear were determined for each sample. Results　The lowered numbers of MHC Class Ⅱ-positive cells in steroid-treatment group murine ears were significantly increased in PS-applied group for 9 days and 23 days（P＜0.05）. Also, an increase tendency in the number for 16 days group was observed（P＝0.059）. The increase in the number in PS-applied group was PS-application time-dependent. The square measure of the epidermis area within 2000 μm from the top in the inner ear was significantly decreased by steroid-treatment（P＜0.05）, though the ear thickness of each group was unchanged. The decreased square measure of the epidermis area was recovered by PS-application time-dependently. The square measure of the epidermis area was significantly increased for 16 days and 23 days（P＜0.05）, and recovered to the level of that of non-steroid-treatment （control）group. Conclusion 　In summary, PS, which can induce remission of atopic dermatitis and other several dermatitis as reported before（Nishikori K, et al. J Am Acad Dermatol Abst 2010; 1308）, was shown to be able to increase the number of MHC Class Ⅱ-positive cells（suggesting the epidermal Langerhans cells）and recovered the shrunk epidermis area in murine ears of steroid-treatment group. This observation may be an epoch-making event in the present situation that there has been neither products which can induce remission of atopic dermatitis, nor is focused on the epidermal Langerhans cells.