GLUTATHIONE ISOPROPYL ESTER REDUCES UVB-INDUCED SKIN DAMAGE IN HAIRLESS MICE

The protective effect of administration of glutathione (GSH) isopropyl ester on photodamage, such as lipid peroxidation, inflammation and tu morigenesis induced by UV exposure (290-400 nm, max, 312 nm), was inve stigated using hairless mice, Pretreatment with 20 mg/kg GSH isopropyl ester prevented the increases of thiobarbituric acid-reactive substan ce (TEARS) formation in skin and serum sialic acid, indices of lipid p eroxidation and inflammatory reaction, respectively, which were caused by a single dose (15 kJ/m(2)) of UV irradiation. The level of epiderm al GSH in skins of the GSH ester-treated mice was maintained within no rmal limits. When mice were exposed to UV at a dose of 2 kJ/m(2), thre e times weekly, skin tumors developed in all of them after 25 weeks. T he formation of skin tumors was significantly inhibited by administrat ion of 10 mg/kg GSH ester prior to each UV irradiation for 25 weeks. M oreover, the increases of cutaneous TEARS and serum sialic acid in the tumor-bearing mice were also prevented by continuous pretreatment wit h GSH ester. Even after 24 weeks, the epidermal GSH content of the pre treated mice was mostly retained compared to nonirradiated mice. Howev er, administration of GSH prior to acute or chronic UV irradiation had no effect on the UV-induced damage. The present results suggest that the protection from photodamage afforded by pretreatment with GSH este r is due to maintenance of a normal GSH level.