title: Dexamethasone treatment reverses cognitive impairment but increases brain oxidative stress in rats submitted to pneumococcal meningitis.
abstract: Pneumococcal meningitis is associated with a significant mortality rate and neurologic sequelae. The animals received either 10 μL of saline or a S. pneumoniae suspension and were randomized into different groups: sham: placebo with dexamethasone 0.7 mg/kg/1 day; placebo with dexamethasone 0.2 mg/kg/7 days; meningitis groups: dexamethasone 0.7 mg/kg/1 day and dexamethasone 0.2 mg/kg/7 days. Ten days after induction we evaluated memory and oxidative stress parameters in hippocampus and cortex. In the step-down inhibitory avoidance task, we observed memory impairment in the meningitis group with dexamethasone 0.2 mg/kg/7 days. The lipid peroxidation was increased in hippocampus in the meningitis groups with dexamethasone and in cortex only in the meningitis group with dexamethasone 0.2 mg/kg/7 days. The protein carbonyl was increased in hippocampus in the meningitis groups with dexamethasone and in cortex in the meningitis groups with and without dexamethasone. There was a decrease in the proteins integrity in hippocampus in all groups receiving treatment with dexamethasone and in cortex in all groups with dexamethasone (0.7 mg/kg/1 day). The mitochondrial superoxide was increased in the hippocampus and cortex in the meningitis group with dexamethasone 0.2 mg/kg/7 days. Our findings demonstrate that dexamethasone reverted cognitive impairment but increased brain oxidative stress in hippocampus and cortex in Wistar rats ten days after pneumococcal meningitis induction.
authors.affiliation: Laboratory of Experimental Microbiology and National Institute for Translational Medicine (INCT-TM), Postgraduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, 88806-000 Criciúma, SC, Brazil. tba@unesc.net
authors.forename: Tatiana
authors.initials: T
authors.lastname: Barichello
authors.forename: Ana Lucia B
authors.initials: AL
authors.lastname: Santos
authors.forename: Cintia
authors.initials: C
authors.lastname: Silvestre
authors.forename: Jaqueline S
authors.initials: JS
authors.lastname: Generoso
authors.forename: Andreza L
authors.initials: AL
authors.lastname: Cipriano
authors.forename: Fabricia
authors.initials: F
authors.lastname: Petronilho
authors.forename: Felipe
authors.initials: F
authors.lastname: Dal-Pizzol
authors.forename: Clarissa M
authors.initials: CM
authors.lastname: Comim
authors.forename: João
authors.initials: J
authors.lastname: Quevedo
mesh_terms: D000818:Animals; D002525:Cerebellar Cortex / Q000187:drug effects* / Q000503:physiopathology; D060825:Cognitive Dysfunction / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D003907:Dexamethasone / Q000008:administration & dosage* / Q000009:adverse effects; D006624:Hippocampus / Q000187:drug effects* / Q000503:physiopathology; D015227:Lipid Peroxidation; D008297:Male; D008569:Memory Disorders; D008586:Meningitis, Pneumococcal / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D018384:Oxidative Stress / Q000187:drug effects; D050050:Protein Carbonylation; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function / Q000187:drug effects
chemical_list: D003907:Dexamethasone