Radioiodine therapy induces dose-dependent in vivo oxidation injury: evidence by increased isoprostane 8-epi-PGF(2 alpha).

Abstract

131I is the treatment of choice for differentiated thyroid cancer and hyperthyroidism. A relationship between low-density lipoprotein oxidation and radioiodine therapy-related side effects, consequently inducing increased formation of 8-epi-prostaglandin F(2 alpha) (PGF(2 alpha)) in situ, has recently been reported by several investigators. Isoprostanes, among them 8-epi-PGF(2 alpha), have been associated with increased oxidation injury due to various pathologic conditions in vivo. The aim of this study was to investigate the possible induction of oxidative stress as a consequence of (131)I therapy. 8-epi-PGF(2 alpha) was examined in plasma, serum, and urine in 42 patients undergoing radioiodine treatment of hyperthyroidism or thyroid cancer. The 8-epi-PGF(2 alpha) levels were analyzed daily for 1 wk and thereafter at different points up to 12 wk after treatment. The isoprostane levels showed an increase after application of radioiodine in all investigated compartments. The effect was significantly higher and longer lasting after higher-activity therapy (2,960 or 7,400 MBq) than after lower-activity therapy (185 or 740 MBq). These findings document a significant, dose-dependent in vivo oxidation injury as a consequence of therapeutic radioiodine application to the salivary gland.