Protection by Food‐derived Antioxidants from UV‐A1‐Induced Photodamage, Measured Using Living Skin Equivalents¶

In a study of biomarkers of ultraviolet‐A1 radiation (UV‐A1)‐induced skin damage, living skin equivalent cultures (LSE) were treated with the antioxidants hesperetin and quercetin‐3‐glucoside and irradiated with 25 or 50 J/cm 2 UV‐A1. Changes in the following biomarkers were measured; Interleukin 1‐alpha (IL‐1α), Heme Oxygenase‐1 (HO‐1), TdT‐mediated dUTP nick end labeling (TUNEL) and 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG). IL‐1α and HO‐1 were analyzed by realtime PCR, Western blot, enzyme‐linked immunosorbent assay (ELISA) and immunohistochemistry. TUNEL and 8‐OHdG were determined by (immuno)histochemical techniques. Sections were stained with hematoxylin and eosin (H&E). UV‐A1 induced keratinocyte and fibroblast vacuolation and nuclear pyknosis, intense TUNEL staining of fibroblasts and increased staining of cells and nuclei for 8‐OHdG. Lesser or marginal increases in intensity followed staining for HO‐1 and IL‐1α. The IL‐1α increase was confirmed by ELISA assays of the medium supernatants. Hesperetin and quercetin‐3‐glucoside reduced changes in H&E, 8‐OHdG, TUNEL and IL‐1α. Quercetin‐3‐glucoside reduced the amount of IL‐1α in LSE media. These observations support the use of the selected biomarkers to monitor UV‐A1 damage and provide evidence that dietary ingredients could reduce ultraviolet‐A radiation‐induced damage.