Ion beam irradiation has different influences on superoxide dismutase activity in cultured human retinal vascular endothelial cells between C and He

ヒト培養網膜血管内皮細胞のSOD活性におけるイオンビーム照射効果のイオン種依存性

明尾 潔*; 舟山 知夫; 小林 泰彦; 明尾 庸子*

Akeo, Kiyoshi*; Funayama, Tomoo; Kobayashi, Yasuhiko; Akeo, Yoko*

イオンビームがヒト培養網膜色素上皮細胞に及ぼす影響を明らかにするために、異なる核種のイオンビームで照射した細胞におけるSuperoxide Dismutase (SOD)活性の測定を実施した。ヒト培養網膜血管内皮細胞にヘリウムイオンビーム、および炭素イオンビームを照射し、照射後0, 4, 8, 24時間後に細胞を採取した。この細胞試料にSODアッセイバッファを加えて凍結解凍を繰り返すことで溶解した細胞抽出液のSOD活性を、ルミノールアッセイ法を用いて定量した。その結果、ヘリウムイオンビームを照射した細胞試料では、照射後の時間経過に伴いSOD活性の低下が進むことが認められたが、炭素イオンビームを照射した細胞では、照射24時間後にSOD活性が上昇することが明らかになった。この結果は、ヘリウムイオンと炭素イオンでは、照射後のSOD活性に及ぼす影響が異なることを示唆する。

It is known that superoxide dismutases (SOD) are a class of enzymes that catalyze the dismutation of superoxide into oxygen and hydrogen peroxide. Ionizing radiation is known to induce oxidative stress through generation of reactive oxygen species resulting in imbalance of the pro-oxidant and antioxidant in the cells, which is suggested to culminate in cell death. Therefore, we measured the activity of SOD in human RE cells exposed to the He- and C-ion beam. The cells collected at 0, 4, 8, and 24 hr after irradiation were extracted by adding the SOD assay buffer to the pellets, and lysed by several cycles of freezing and thawing. The activity of SOD was measured using a modification of the luminol assay. SOD activity decreased according to duration time after irradiation of He-ion, however, in case of C-ion, it increased at 24 hr after irradiation. The result suggested that that there were the differences of the effects by irradiation on SOD activity between He- and C-ion.