Brain Oxidative Damage Following Acute Immobilization and Mild Emotional Stress

We studied the role of free radicals on brain oxidative damage in rats after acute immobilization stress (restraint) and mild emotional stress (handling). To investigate brain oxidative damage, CuZn and Mn dependent superoxide dismutase (CuZn SOD, Mn SOD) activities, lipid peroxidation (TBARs), Na⁺K⁺ATPase activity, protein carbonyl (PrC), and reduced and oxidized glutathione (GSH, GSSG) levels were measured in the cerebral cortex (CTX), hippocampus (HIP), and striatum (ST) of the animals after the two different stress stimuli. Because stress produces abnormalities in the hypothalamic-pituitary-adrenal axis, the intensity of the two stress conditions were measured by plasmatic corticosteroid (COR) levels: particularly, COR levels doubled in handled rats and increased 15-fold in restrained animals. The SOD activities increased in CTX and decreased in HIP of the handled rats, while in ST a significant decrease in handled animals but an increase in restrained animals occurred. TBARs, GSH, and GSSG levels remained unchanged, while an index of glutathione redox decreased significantly in ST of handled animals and in CTX of restrained ones. Na⁺K⁺ATPase activity increased significantly in the HIP and ST of both groups of stressed rats. The stress induced a remarkable increase in PrC levels in all studied cerebral areas. These findings provide evidence to support the idea that stress produces oxidants but that the oxidative damage in stress differs in cerebral areas and could contribute to the degenerative mechanism of aging.