The size effects of amorphous silica nanoparticles on atopic dermatitis-like skin lesion (P6259)

Abstract

Exposure to environmental factors, such as microbes, diesel exhaust, and other chemicals are speculated to be associated with atopic dermatitis (AD), however, the detailed relationships between environmental factors and increase in AD are not well understood. Additionally, recent industrialization poses new threats to the development of AD. We recently revealed that amorphous silica nanoparticles (nSP) can penetrate the skin barrier and induce various immunological effects. Thus, nSP in various products may also be associated with development of the other allergic diseases such as AD. Here, we investigated the effect of nSPs on AD like skin lesions. We injected mite antigen (Dp) plus various-sized silica particles (SPs : diameter of 1,000, 300, 100, 70 and 30 nm) intradermally into the ear of NC/Nga mice which develops AD-like skin lesions induced by a mite allergen Dp. Ear thickness measurements and histopathological analysis revealed that a combined injection of SPs and Dp induced aggravation of AD in an SP size-dependent manner compared to that of Dp alone. Furthermore, these effects were correlated with the excessive induction of total IgE and Dp specific IgE. We suggested that these results are associated with the induction of IL-18 and thymic stromal lymphopoietin (TSLP), which leads to systemic Th2 response in the skin lesions. These results indicate that the size of SPs is critical determinant in terms of their safe use.