Luteolin reduces high glucose-mediated impairment of endothelium-dependent relaxation in rat aorta by reducing oxidative stress.

While luteolin, a flavone rich in many plants, has some cardiovascular activity, it is not clear whether luteolin has beneficial effects on the vascular endothelial impairment in hyperglycemia/high glucose. Here, we reveal the protective effect of luteolin on endothelium-dependent relaxation in isolated rat aortic rings exposed to high glucose. The thoracic aorta of male Sprague-Dawley rats was rapidly dissected out and the effect of luteolin on the tension of aortic rings pretreated with high glucose (44mM) for 4h was measured in an organ bath system. The levels of nitric oxide (NO), hydroxy radical (OH(-)) and reactive oxygen species (ROS), and the activity of superoxide dismutase (SOD) and nitric oxide synthase (NOS) were measured in aortas. The vasorelaxation after treatment with luteolin for 8 weeks in aortic rings from diabetic rats was also determined. We found that exposure to high glucose decreased acetylcholine-induced endothelium-dependent relaxation. However, high mannitol had no effect on vasorelaxation. Luteolin evoked a concentration-dependent relaxation in aortic rings previously contracted by phenylephrine, and the pD(2) value was 5.24+/-0.04. The EC(50) of luteolin markedly attenuated the inhibition of relaxation induced by high glucose, which was significantly weakened by pretreatment with l-NAME (0.1mM), but not by indomethacin (0.01mM). Luteolin significantly inhibited the increase of ROS level and OH(-) formation, and the decrease of NO level, NOS and SOD activity caused by high glucose. The improving effect of luteolin on endothelium-dependent vasorelaxation in diabetic rat aortic rings was reversed by pretreatment with l-NAME or methylene blue. The results indicate that the decrease of endothelium-dependent relaxation in rat aortic rings exposed to high glucose is markedly attenuated by luteolin, which may be mediated by reducing oxidative stress and enhancing activity in the NOS-NO pathway.

Reconstruction of a new pulmonary artery in arterial switch operation.

BACKGROUND: This study was undertaken to evaluate the new method for the reconstruction of the pulmonary artery in arterial switch operation (ASO). METHODS: A total of 108 consecutive infants with congenital heart disease were treated with ASO in our department between January 2004 and June 2012. The new pulmonary arterial root was reconstructed with a fresh autologuos pericardium which was clipped pants-like with continuous mattress suture of 6-0 Prolene thread. Patients were reexamined consecutively at 3 and 6 months and 1, 2 and 6 years after discharge. The pulmonary arterial blood velocity was measured by continuous Doppler during systole. The pulmonary flow of healthy children of same age was also measured in the control group. Simplified Bernoulli formula was used to calculate the pressure gradient via the pulmonary artery for determining whether there was pulmonary stenosis. RESULTS: In this series, 96 infants survived after the surgery and 88 were followed up with a mean peirod of (22±4) months. No pulmonary stenosis was detected with the simplified Bernoulli formula. CONCLUSION: No pulmonary stenosis was detected with the simplified Bernoulli formula.