RAT EMBRYOS CULTURED UNDER COPPER-DEFICIENT CONDITIONS DEVELOP ABNORMALLY AND ARE CHARACTERIZED BY AN IMPAIRED OXIDANT DEFENSE SYSTEM

Rat embryos (gestation days 9.0 and 10.0) obtained from darns that wer e fed a Cu-adequate (8 mu g Cu/g) or Cu-deficient (<0.5 mu g Cu/g) die t were cultured for 48 hr in Cu-adequate (16.2 mu M) or Cu-deficient ( 1.0 mu M) rat serum. Control embryos cultured in control serum were mo rphologically normal. Embryos from Cu-deficient dams developed abnorma lly when cultured in Cu-deficient serum; the abnormalities included di stended hindbrains, blisters, blood pooling, and cardiac defects. Cont rol embryos cultured in Cu-deficient serum and Cu-deficient embryos cu ltured in control serum also showed abnormal development, but to a les ser degree than that of the Cu-deficient embryos cultured in Cu-defici ent serum. To test the idea that the above abnormalities were due in p art to free radical-induced damage occurring secondary to an impaired oxidant defense system, a chemiluminescence assay was used to detect s uperoxide dismutase (SOD) activity in the cultured embryos, SOD activi ty was lowest in embryos cultured in Cu-deficient serum. When the Cu-d eficient serum was supplemented with antioxidants (CuZnSOD or glutathi one peroxidase), its teratogenicity was reduced. These data support th e idea that an impaired oxidant defense system contributes to the dysm orphology associated with Cu deficiency. However, the Cu-deficient emb ryos also had low cytochrome c oxidase activity compared to control em bryos-thus, multiple factors are likely contributing to Cu deficiency- induced abnormalities. (C) 1998 Wiley-Liss, Inc.