Decreased reactive oxygen species production and NOX1, NOX2, NOX4 expressions contribute to hyporeactivity to phenylephrine in aortas of pregnant SHR.

AIMS: We determined whether decreased reactive oxygen species (ROS) production in the aorta of pregnant spontaneously hypertensive rats (SHR) resulted in increased nitric oxide (NO) bioavailability and hyporeactivity to phenylephrine (PE). MAIN METHODS: Systemic and aortic oxidative stress were measured in pregnant and non-pregnant Wistar rats and SHR. Furthermore, the hypotensive effects of apocynin (30 mg/kg) and Tempol (30 mg/kg) were analyzed. Intact aortic rings of pregnant and non-pregnant rats were stimulated with PE in the absence of or after incubation (30 min) with apocynin (100 µmol/L). The effect of apocynin on the concentrations of NO and ROS were measured in aortic endothelial cells (AEC) using DAF-2DA (10 mmol/L) and DHE (2.5 mmol/L), respectively. Western blotting was performed to analyze eNOS, NOX1, NOX2, NOX4 and SOD expression. ROS production was analyzed by the lucigenin chemiluminescence method. KEY FINDINGS: Aortic oxidative stress and ROS concentration in AEC were reduced in pregnant Wistar rats and SHR, when compared to non-pregnant rats. ROS production and NOX1, NOX2 and NOX4 expression in the aortas were decreased in pregnant SHR, but not in pregnant Wistar rats. Increased eNOS expression in aortas and NO concentration in AEC were observed in pregnant Wistar rats and SHR. Apocynin reduced PE-induced vasoconstriction in the aortas of non-pregnant Wistar rats and SHR, and pregnant Wistar rats, but not in the aortas of pregnant SHR. SIGNIFICANCE: Taken together, these results suggest that ROS production was decreased in the aortas of pregnant SHR and could contribute to higher NO bioavailability and hyporeactivity to PE in the aortas of pregnant SHR.

Papel do PMN na falencia de multiplos orgaos e sistemas / Role of the polymorphonuclear neutrophil in the failure of multiple organs and systems

Os autores analisam o papel do neutrofilo polimorfonuclear (PMN) na FMOS pos-trauma e cirurgia, papel este atribuido quer a ativacao para producao de radicais superoxidos e enzimas, quer a depressao funcional dos PMNs. Destacam: 1) a investigacao da sequencia de transmissao intracelular de sinais entre receptores de membrana do PMN e a resposta efetora final; 2) a estrutura e funcao do sistema NADPH do PMN; 3) os estados funcionais do PMN (quiescente, sensibilizado, ativado ou responsivo) em termos de ativacao do sistema NADPH; 4) o mecanismo de lesao tecidual pelo PMN. Discutem investigacoes clinicas sobre o estado de ativacao do PMN, e abordam as perspectivas terapeuticas apontadas pelas pesquisas recentes