Figure 3. Imbalance of oxidative stress and the antioxidant system in Cygb^−/− mice.

(A) Total concentrations of nitrite and nitrate, oxidised forms of nitrogen, in the serum (left-panel) and urine (right-panel) of young and aged WT and KO mice. (B) Immunoblots for nitrotyrosine (NT), an indicator or marker of cell damage, inflammation and NO (nitric oxide) production, in aged WT, KO non-tumour, and KO liver tumour area. GAPDH, loading control. All gels were run under the same experimental conditions. Cropped gels were used, and full-length gels are presented in Supplementary Fig. S4. (C) Concentration of malondialdehyde (MDA), an end product of lipid peroxidation, in the liver and serum of young WT and KO mice. (D) Total glutathione (GSH) in the serum of young and aged WT and KO mice (left-panel) and GSH/oxidised GSH (GSSG) ratio in the liver tissues (right-panel) of aged WT and KO mice. (E) The increased hepatic mRNA transcript levels of the pro-oxidant genes inducible nitric oxide synthase (iNos), myeloperoxidase (Mpo) (top panels) are opposite to the decreased expression of the antioxidant genes superoxide dismutase 2 (Sod-2) and catalase-1 (Cat-1) (bottom panels). (F) Liver sections of aged WT and KO mice were immunohistochemical stained for neutrophil and haem oxygenase-1 (HO-1). Bottom inset, hepatic mRNA levels of Ho-1. Open bar, WT; closed bar, KO. Young mice: ≤12 months of age; aged mice: 13–24 months. Data represent the mean ± SD; n = 10–15 per group. *p < 0.05; **p < 0.01; ***p < 0.001.