Expression of oxidative stress-response genes is not activated in the prefrontal cortex of patients with depressive disorder.

To test the hypothesis that the oxidative stress consistently detected in the peripheral blood of patients with depressive disorder impacts on the functionally relevant brain region, the expression level of nine major genes of the stress response and repair systems has been quantified in the prefrontal cortex of 24 depressive and 12 control subjects. These genes were: superoxide dismutase (SOD1), SOD2, catalase (CAT), gluthatione peroxidase 1 (GPx1), 8-oxoguanine DNA glycosylase (OGG1), nei-like 1 (NEIL1), methionine sulphoxide reductase A (MSRA), telomere repeat-binding factor 2 (TERF2) and C-FOS. Telomere length (a maker of chronic exposure to oxidative stress) has been measured in the DNA of the occipital cortex. No significant difference has been found between the compared groups. It must be concluded that the pathogenic role of the oxidative stress in the cerebral mechanism of depression cannot be inferred from the alteration of peripheral parameters.