Effects of UVB Radiation on the Physicochemical Properties of Fibroblasts and Keratinocytes

The skin is the largest human organ, providing the first line of defense to protect the body from physical and environmental effects. The aim of this study was to determine the influence of short-wave ultraviolet (UVB) radiation on the membrane electrical properties, phospholipid content, and lipid peroxidation levels of fibroblasts and keratinocytes. Changes in cell function may affect the basal electrical surface properties of cell membranes. These changes can be detected using electrokinetic measurements. In this study, the surface charge densities of fibroblasts and keratinocytes were measured as a function of pH. A four-component equilibrium model was used to describe the interaction between the ions in solution and on cell membrane surfaces. Agreement was found between the experimental and theoretical charge variation curves of leukemia cells from pH 2.5 to pH 9. Phospholipid composition was determined qualitatively and quantitatively by HPLC, and lipid peroxidation was estimated by measuring the level of malondialdehyde. The acidic functional group concentrations and average association constants with hydroxyl ions were higher, and the average association constants with hydrogen ions were smaller in UVB-treated skin cell membranes compared to those in untreated cells. Moreover, our results showed that UVB radiation is associated with increased levels of phospholipids and lipid peroxidation products in fibroblasts and keratinocytes.