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.

Femoral biomechanic and microtomography from male ratssubmitted to dietary restriction supplemented with sucrose

Food restriction reduces body weight and influence bone mass and also is correlated with bone mineraldensity (BMD). Mechanisms have been proposed for the loss of BMD after body weight reduction, includingreduced energy intake. Growing 8 wk-old Wistar male rats were randomly divided into Control and Calorierestriction associated with sucrose 30% (CRS). These animals were subjected to intermittent food restrictionduring 8 weeks and had free access to tap water and sucrose30% in distilled water. The rats were euthanizedat the end of week 8, blood collected from abdominal aorta artery, femurs cleaned of adherent soft tissues,scanned using dual energy X-ray absorptiometry, structural and material properties determined by three-pointbending testing in the mid-diaphyseal region, bone surface tested in a microhardness tester and microstructurewas assessed in a microcomputer tomography. In CRS animals body weight decreased significantly relative tothe Control animals. There was a clear option for high-sucrose beverage in CRS animals. No difference wasobserved in biochemical, densitometric and biomechanical analyzes. Results from micro CT showed onlysignificant difference in connectivity of trabecular bone. It has been suggested that rats submitted to foodrestriction consumed sugar not because of its inherent palatability, but in order to alter their macronutrientbalance and animals need to meet energy demands in high-sucrose.