The Effects of ultraviolet irradiation and hypoxia on expression of glutathione peroxidase and glyceraldehyde 3-phosphate dehydrogenase in the cultured retinal pigment epithelium

Akeo, Kiyoshi*; Funayama, Tomoo; Hamada, Nobuyuki*; Akeo, Yoko*; Hiramitsu, Tadahisa*; Kobayashi, Yasuhiko

Glutathione peroxidase (GPX) protects the phospholipids in the biomembrane barrier from damage by the free radicals. We studied cultured bovine retinal pigmented epithelial (RPE) cells exposed to UV-A and UV-B to try to determine the expression of GPX and glyceraldehdye-3-phosphate dehydrogenase (GAPDH) that are highly sensitive to oxidation. The total cellular RNA of the RPE cells was reverse transcribed by using primers for GPX and GAPDH. The quantitative real-time RT-PCR was performed to compare the effects of UV-A and UV-B irradiation on 18S ribosomal RNA (rRNA) and GPX expression using the LightCycler system. The expression of GAPDH and GPX was decreased by hyperoxia such as 20% oxygen and UV-B irradiation using electrophoresis. The LightCycler analysis, the quantitative real-time RT-PCR, showed that UV-A exposure at a small dose induced the defense mechanism against lipid peroxidation in RPE cells. However, UV-A exposure at a large dose led to a disturbance in the defense mechanism similar to that observed with UV-B irradiation; this could have a relationship with retinal diseases caused by light damage.