Topically applied ZnO nanoparticles suppress allergen induced skin inflammation but induce vigorous IgE production in the atopic dermatitis mouse model

Abstract

BackgroundMetal oxide nanoparticles such as ZnO are used in sunscreens as they improve their optical properties against the UV-light that causes dermal damage and skin cancer. However, the hazardous properties of the particles used as UV-filters in the sunscreens and applied to the skin have remained uncharacterized.MethodsHere we investigated whether different sized ZnO particles would be able to penetrate injured skin and injured allergic skin in the mouse atopic dermatitis model after repeated topical application of ZnO particles. Nano-sized ZnO (nZnO) and bulk-sized ZnO (bZnO) were applied to mechanically damaged mouse skin with or without allergen/superantigen sensitization. Allergen/superantigen sensitization evokes local inflammation and allergy in the skin and is used as a disease model of atopic dermatitis (AD).ResultsOur results demonstrate that only nZnO is able to reach into the deep layers of the allergic skin whereas bZnO stays in the upper layers of both damaged and allergic skin. In addition, both types of particles diminish the local skin inflammation induced in the mouse model of AD; however, nZnO has a higher potential to suppress the local effects. In addition, especially nZnO induces systemic production of IgE antibodies, evidence of allergy promoting adjuvant properties for topically applied nZnO.ConclusionsThese results provide new hazard characterization data about the metal oxide nanoparticles commonly used in cosmetic products and provide new insights into the dermal exposure and hazard assessment of these materials in injured skin.

Nanoparticles enhance the ability of human neutrophils to exert phagocytosis by a Syk-dependent mechanism

“…This is particularly true for TiO 2 , CeO 2 and ZnO NPs that were found to induce inflammation in some studies [37][38][39][40], whereas they were found to possess anti-inflammatory properties in others [41][42][43]. This illustrates how complex is the study of NPs in in vivo biological systems.…”

Comparison of distribution and toxicity of different types of zinc‐based nanoparticles

“…Moreover, although it is still under debate, the effects of ZnO NPs on the immune system have been raised in some studies (Kim et al, ; Roy et al, ). For example, topical application of ZnO NPs reduced local skin inflammation but induced systemic production of IgE antibodies in the atopic dermatitis model (Ilves et al, ). Additionally, ZnO NPs (750 mg/kg/day) administered orally for 14 days suppressed innate immunity without an effect on the T cell‐mediated immune response, the ratio of CD4+/CD8+, subtypes of T cells, was slightly reduced, and serum levels of pro‐, anti‐, and Th1 type‐inflammatory cytokines were significantly inhibited in mice exposed to ZnO NPs compared to the control (Kim et al, ).…”

A novel glycocluster molecule prevents timothy‐induced allergic airway inflammation in mice

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