title: Neonatal hyperglycemia induces oxidative stress in the rat brain: the role of pentose phosphate pathway enzymes and NADPH oxidase.
abstract: Recently, the consequences of diabetes on the central nervous system (CNS) have received great attention. However, the mechanisms by which hyperglycemia affects the central nervous system remain poorly understood. In addition, recent studies have shown that hyperglycemia induces oxidative damage in the adult rat brain. In this regard, no study has assessed oxidative stress as a possible mechanism that affects the brain normal function in neonatal hyperglycemic rats. Thus, the present study aimed to investigate whether neonatal hyperglycemia elicits oxidative stress in the brain of neonate rats subjected to a streptozotocin-induced neonatal hyperglycemia model (5-day-old rats). The activities of glucose-6-phosphate-dehydrogenase (G6PD), 6-phosphogluconate-dehydrogenase (6-PGD), NADPH oxidase (Nox), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), the production of superoxide anion, the thiobarbituric acid-reactive substances (TBA-RS), and the protein carbonyl content were measured. Neonatal hyperglycemic rats presented increased activities of G6PD, 6PGD, and Nox, which altogether may be responsible for the enhanced production of superoxide radical anion that was observed. The enhanced antioxidant enzyme activities (SOD, CAT, and GSHPx) that were observed in neonatal hyperglycemic rats, which may be caused by a rebound effect of oxidative stress, were not able to hinder the observed lipid peroxidation (TBA-RS) and protein damage in the brain. Consequently, these results suggest that oxidative stress could represent a mechanism that explains the harmful effects of neonatal hyperglycemia on the CNS.
authors: Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil, deia1018@hotmail.com.
authors: Andrea Pereira
authors: AP
authors: Rosa
authors: Carlos Eduardo Dias
authors: CE
authors: Jacques
authors: Laila Oliveira
authors: LO
authors: de Souza
authors: Fernanda
authors: F
authors: Bitencourt
authors: Priscila Nicolao
authors: PN
authors: Mazzola
authors: Juliana Gonzales
authors: JG
authors: Coelho
authors: Caroline Paula
authors: CP
authors: Mescka
authors: Carlos Severo
authors: CS
authors: Dutra-Filho
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000201:enzymology* / Q000473:pathology*; D002374:Catalase / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D006943:Hyperglycemia / Q000473:pathology*; D019255:NADPH Oxidases / Q000378:metabolism*; D018384:Oxidative Stress; D010427:Pentose Phosphate Pathway; D050050:Protein Carbonylation; D017208:Rats, Wistar; D013481:Superoxides / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D017392:Thiobarbituric Acid Reactive Substances; D013481:Superoxides; D002374:Catalase; D005979:Glutathione Peroxidase; D019255:NADPH Oxidases