Embryo

Copper-Deficient Rat Embryos Are Characterized by Low Superoxide Dismutase Activity and Elevated Superoxide Anions

Abstract

The teratogenicity of copper (Cu) deficiency may result from increased oxidative stress and oxidative damage. Dams were fed either control (8.0 µg Cu/g) or Cu deficient (0.5 µg Cu/g) diets. Embryos were collected on gestation day 12 for in vivo studies, or on gestation day 10 and cultured for 48 h in Cu deficient or Cu adequate media for in vitro studies. Superoxide dismutase (SOD), glutathione peroxidase (GPX), and glutathione reductase (GR) activities were measured in control and Cu deficient embryos as markers of the oxidant defense system. Superoxide anions were measured as an index of exposure to reactive oxygen species (ROS). There were no differences in GPX or GR activities among treatment groups. SOD activity was lower, and superoxide anion concentrations were higher in Cu deficient embryos cultured in Cu deficient serum compared to control embryos cultured in control serum. However, Cu deficient embryos had similar CuZnSOD protein levels as controls. In the in vitro system, Cu deficient embryos had a higher frequency of malformations and increased staining for superoxide anions in the forebrain, heart, forelimb and somites compared to controls. When assessed for lipid and DNA oxidative damage, conjugated diene concentrations were similar among the groups; but there was a tendency for Cu deficient embryos to have higher 8-hydroxy-2'deoxyguanosine concentrations than controls. Thus, Cu deficiency resulted in embryos with malformations and reduced SOD enzyme activity. Increased ROS concentrations in the Cu deficient embryo may cause oxidative damage and contribute to the occurrence of developmental defects.