title: Different susceptibility of prefrontal cortex and hippocampus to oxidative stress following chronic social isolation stress.
abstract: Chronic oxidative stress plays an important role in depression. The aim of present study was to examine the stress-induced changes in serum corticosterone (CORT) levels, cytosolic protein carbonyl groups, malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide (NO) and total superoxide dismutase (SOD) activity in the prefrontal cortex versus hippocampus of male Wistar rats exposed to acute (2 h of immobilization or cold), chronic (21d of social isolation) stress, and their combination (chronic + acute stress). The subcellular distribution of nuclear factor-κB (NF-κB) and cytosolic cyclooxygenase 2 (COX-2) protein expressions were also examined. Depressive- and anxiety-like behaviors were assessed via the forced swim, sucrose preference, and marble burying tests in chronically isolated rats. Although both acute stressors resulted in elevated CORT, increased MDA in the prefrontal cortex and NF-κB activation accompanied by increased NO in the hippocampus were detected only following acute cold stress. Chronic isolation resulted in no change in CORT levels, but disabled appropriate response to novel acute stress and led to depressive- and anxiety-like behaviors. Increased oxidative/nitrosative stress markers, likely by NF-κB nuclear translocation and concomitant COX-2 upregulation, associated with decreased SOD activity and GSH levels, suggested the existence of oxidative stress in the prefrontal cortex. In contrast, hippocampus was less susceptible to oxidative damage showing only increase in protein carbonyl groups and depleted GSH. Taken together, the prefrontal cortex seems to be more sensitive to oxidative stress than the hippocampus following chronic isolation stress, which may be relevant for further research related to stress-induced depressive-like behavior.
authors.affiliation: Laboratory of Molecular Biology and Endocrinology, Institute of Nuclear Sciences "Vinča", University of Belgrade, P. O. Box 522-090, 11001, Belgrade, Serbia.
authors.forename: Jelena
authors.initials: J
authors.lastname: Zlatković
authors.forename: Nevena
authors.initials: N
authors.lastname: Todorović
authors.forename: Maja
authors.initials: M
authors.lastname: Bošković
authors.forename: Snežana B
authors.initials: SB
authors.lastname: Pajović
authors.forename: Miroslav
authors.initials: M
authors.lastname: Demajo
authors.forename: Dragana
authors.initials: D
authors.lastname: Filipović
mesh_terms: D000818:Animals; D003345:Corticosterone / Q000097:blood; D051546:Cyclooxygenase 2 / Q000097:blood; D005978:Glutathione / Q000097:blood; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D016328:NF-kappa B / Q000097:blood; D009569:Nitric Oxide / Q000097:blood; D018384:Oxidative Stress; D017397:Prefrontal Cortex / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012934:Social Isolation / Q000523:psychology; D013315:Stress, Psychological; D013482:Superoxide Dismutase
chemical_list: D016328:NF-kappa B; D009569:Nitric Oxide; D051546:Cyclooxygenase 2; D013482:Superoxide Dismutase; D005978:Glutathione; D003345:Corticosterone