Increased oxidative DNA damage, lipid peroxidation, and reactive oxygen species in cultured orbital fibroblasts from patients with Graves’ ophthalmopathy: evidence that oxidative stress has a role in this disorder

Abstract

We investigated the oxidative stress in orbital fibroadipose tissues and cultured orbital fibroblasts from patients with Graves' ophthalmopathy (GO). The content of 8-hydroxy 2'-deoxyguanosine (8-OHdG), an important biomarker of oxidative DNA damage, was measured in orbital fibroadipose tissues and cultured orbital fibroblasts from patients with GO and compared with age-matched normal controls. A product of lipid peroxidation, malondialdehyde (MDA), and intracellular reactive oxygen species (ROS) in cultured orbital fibroblasts was also determined. There was no significant difference in the 8-OHdG content of orbital fibroadipose tissues between patients with GO and age-matched normal controls (P=0.074). However, the levels of 8-OHdG and MDA in GO orbital fibroblasts were significantly higher than those of normal controls (P=0.0026 and P<0.001, respectively). In addition, GO orbital fibroblasts had higher contents of superoxide anions and hydrogen peroxide compared with those of normal controls (P=0.0133 and 0.0025, respectively). Orbital fibroblasts represent the most abundant cell type among orbital connective tissues and exhibit great differences in their phenotypes. Increased oxidative DNA damage and lipid peroxidation, as well as higher intracellular ROS levels in GO orbital fibroblasts may have a role in the pathogenesis of GO.