MEMBRANE DAMAGE-INDUCED IN CULTURED HUMAN SKIN FIBROBLASTS BY UVA IRRADIATION

Irradiation of cultured human skin fibroblasts with ultraviolet light from 320 to 400 nm (UVA) leads to a decrease in the membrane fluidity exemplified by an enhanced fluorescence anisotropy of the lipophilic f luorescent probe trimethylamino)-phenyl]-6-phenylhexa-1,3,5-triene. Th is UVA-induced decrease in fluidity is associated with lactate dehydro genase leakage in the supernatant. Vitamin E, an inhibitor of lipid pe roxidation, exerts a protective effect on both phenomena. Therefore, t his UVA-induced damage in membrane properties may be related to lipid peroxidation processes. Moreover, exponentially growing cells are more sensitive to these UVA-induced alterations than confluent cells.