690 A novel water-in-oil emulsion with a natural surfactant modified clay prevents skin damage from urban dust and cedar pollen

Abstract

Air pollutants and pollens cause skin inflammation and aging. It is important to protect the skin from particulate matter and to develop formulations composed of natural ingredients for avoidance of environmental pollution. Previously, we developed a conventional water-in-oil emulsion with a synthetic surfactant modified clay (C-W/O), which protects the skin from allergens. In this study, we developed a novel water-in-oil emulsion with a natural surfactant modified clay (N-W/O). We performed microarray analysis using total RNA extracted from reconstructed human epidermis stimulated with urban aerosols or cedar pollens for 6 hours as a model of epidermal inflammation. The expression levels of pro-inflammatory cytokines and chemokines, such as IL1B and CXCL8, and matrix metalloproteinases, such as MMP1, MMP3, and MMP9, were significantly upregulated by particulate matter stimulation. Next, we compared the efficacy of N-W/O and C-W/O to prevent epidermal degradation. Tissues and culture media were collected 24 hours after particulate matter stimulation for histological assay and quantification of CXCL8 and MMP1 secretion. A thickened stratum corneum, thinned vital layer, and cleaved E-cadherin were observed by hematoxylin and eosin (H&E) staining and immunohistochemical staining of E-cadherin, and the levels of CXCL8 and MMP1 secretion in the media were significantly increased. N-W/O prevented degradation of epidermal integrity and the secretion of inflammatory proteins more than C-W/O. Taken together, our data suggest that N-W/O is better than C-W/O because it is composed of natural ingredients and protects the skin from particulate matter such as urban aerosols and cedar pollens.