engleski

Attenuated flow-induced dilation of middle cerebral arteries is related to increased vascular oxidative stress in rats on a short- term high salt diet

Aim was to determine flow-induced dilation (FID) and the role of oxidative stress/antioxidative capacity in isolated, pressurized middle cerebral arteries (MCA) of high salt (HS) fed rats. 11-weeks old healthy male Sprague-Dawley rats were fed 0.4%NaCl (low salt (LS) group) or 4%NaCl (HS group) diet for 1 week. Reactivity of MCA in response to stepwise increase in pressure gradient (Δ10-Δ100 mmHg) was determined in the absence or presence of superoxide dismutase (SOD) mimetic TEMPOL and/or nitric oxide synthases (NOS) inhibitor Nω -nitro-L-arginine methyl ester (L-NAME). mRNA levels of antioxidative enzymes, NAPDH- oxidase components, inducible (iNOS) and endothelial nitric oxide synthases (eNOS) were determined by quantitative real-time PCR. Blood pressure, antioxidant enzymes' activity, oxidative stress in peripheral leukocytes, lipid peroxidation products and antioxidant capacity of plasma were measured for both groups. FID was reduced in HS group compared to LS group. The presence of TEMPOL restored dilation in HS group, with no effect in LS group. Expression of glutathione peroxidase 4 (GPx4) and iNOS in HS group was significantly decreased ; oxidative stress was significantly higher in HS group compared to LS group. HS intake significantly induced basal reactive oxygen species production in the leukocytes of mesenteric lymph nodes and splenocytes, and intracellular production after stimulation in peripheral lymph nodes. Antioxidant enzymes activity and BP were not affected by HS diet. Low GPx4 expression, increased superoxide production in leukocytes, together with decreased iNOS expression likely underlies increased oxidative stress and reduced nitric oxide bioavailability which caused impairment of FID in HS group without changes in BP values. This article is protected by copyright. All rights reserved.

antioxidative enzymes ; flow-induced dilation ; high salt diet ; middle cerebral artery ; oxidative stress

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