1055 Evaluation of film dressings for the prevention of intraepidermal nerve growth and alloknesis (touch-evoked itch) in murine dry skin models

Abstract

Epidermal hyperinnervation is observed in dry skin diseases such as xerosis and atopic dermatitis. Such diseases manifest in low-threshold mechanical stimuli irritation of the skin, which is known as alloknesis. Increased intraepidermal nerve fibers are thought to be one of the pathogenic factors in itch hypersensitivity. Film dressings for wound treatment act as a skin barrier and provide a moist environment. However, it has not been clear whether film dressings have any preventive effects on epidermal hyperinnervation and alloknesis in dry skin diseases. We evaluated two different thickness film dressings, TEGADERM (TDM) and PERME ROLL Lite (PMR), for their preventive effect on epidermal hyperinnervation using an acute dry skin model. Twenty square millimeters of TDM or PMR was applied after 5-min acetone treatment to the back skin of ICR mice. Skin samples were taken after an additional 48 h. Immunohistochemically, the numbers of protein gene product 9.5-immunoreactive nerve fibers in and penetrating into the epidermis were significantly decreased by TDM or PMR treatment. We further evaluated alloknesis using a chronic dry skin model. A mixture of acetone and diethylether (1:1) for 15 s followed by distilled water for 30 s (AEW) was applied to the back skin of C57BL/6NCrSlc mice twice daily for 8 days. TDM or PMR with a diameter of 8 mm was applied on the AEW-treated site on the day after the last treatment. Alloknesis assays showed that TDM and PMR application significantly prevented induction of alloknesis. These findings suggest that the film dressings not only prevent epidermal hyperinnervation by moisturization but also reduce alloknesis by inhibiting the transmission of mechanical stimuli.