Oxidative effects of cigarette smoke on the human skin

The oxidative effects of cigarette smoke on the human skin were investigated. A remarkable increase in the conversion ratio of squalene (SQ) to squalene monohydroperoxide (SQHPO) due to exposure to cigarette smoke was observed using a CL-HPLC (high performance liquid chromatography with a chemiluminescence detector) system. The results showed that cigarette smoke caused lipid peroxidation. We also found that the addition of chain-breaking-type antioxidants, such as oolong tea extract, inhibited the peroxidation. When cultured human skin fibroblasts were exposed to cigarette smoke, this increased the intensity of ultraweak chemiluminescence (CL), leading us to assume that cigarette smoke caused oxidation in cultured human skin fibroblasts. When the cultured human skin fibroblasts were treated with antioxidants such as glutathione, thiotaurine, hypotaurine and ascorbic acid there was little increase in CL, meaning that oxidation had been prevented in the human skin fibroblasts. We also exposed the human forearm to cigarette smoke and obtained sebum using cotton immersed in acetone in order to measure hydroperoxide levels by means of a CL-HPLC system. The exposure of skin to the smoke caused a dose-dependent increase in hydroperoxides derived from cigarette smoke. Further exposure of the forearm to cigarette smoke increased the intensity of CL, but pretreating the skin with antioxidants such as glutathione, thiotaurine and hypotaurine inhibited this increase. From these results, we concluded that cigarette smoke had an oxidative effect on SQ, cultured human skin fibroblasts and the surface of the human skin. The application of antioxidants prevented the cigarette smoke-induced oxidation. We consider that these oxidative effects on the skin could be a cause of skin disorders and skin aging.