Differential response to lipid peroxidation in male and female mice with age: correlation of antioxidant enzymes matters.

The aim of this study was to correlate the activity of superoxide dismutase, catalase and glutathione peroxidase in liver and brain of 1, 4 and 18 months old CBA mice of both sexes. In liver, decreased superoxide dismutase and increased glutathione peroxidase activities were observed during aging in male mice. In brain, the increase of catalase and glutathione peroxidase activity during aging was observed only in female mice. Regardless of tissue examined, different sex-related correlation pattern of antioxidant enzyme activity was demonstrated in young and old mice. The cooperation between antioxidant enzymes becomes more coherent with increased lipid peroxidation concentration in liver and brain of older female mice. On the contrary, in older male mice the link among three antioxidant enzymes becomes weaker, regardless of lipid peroxidation concentration which increased in liver and decreased in brain during aging. In older mice lower partial coefficient of correlation than pair correlation demonstrates the influence of the third party in the cooperation of two antioxidant enzymes. The results imply stronger correlative links in old female than male mice, which might explain why old females are better protected from oxidative stress than males.