Shielding response of rodent skin to water soluble ambient air pollutants

Given the increasing levels of air pollution, understanding the direct shielding response of the skin to air pollutants as a whole under exclusion of the influence from the inside of body is important. We applied topically the water soluble ambient air pollutants to the mouse skin and observed the histological response using 0.3 mM of H₂SO₃ as a positive control. Water soluble air pollutants samples, WSAP24h and WSA72h, were collected by pumping the outdoor air into ddH₂O for 24 and 72 h respectively during two periods with different air quality index (AQI). Morphological examination showed apparent thickening of the epidermal layer in the H₂SO₃ skin section and in the sections applied with WSAP24h and WSAP72h without significant difference in the extent of epidermal hyperplasia among three groups. The cell viability assay showed no cytotoxic effect by the treatment of H₂SO₃ and WSAP24h in human skin fibroblast WS-1 cells. WSAP72h sample revealed a dose-dependent cytotoxicity to skin fibroblasts at 48 hr. The evidences indicated that the barrier function of the skin by epidermis hyperplasia could be activated by the insult of a component of air pollution, and the protection could be hold against a more complex and concentrated ambient air pollutants.