Key result
Introgressing the Brown Norway renin allele onto the Dahl salt-sensitive background significantly increased Cu/Zn SOD expression and lowered vascular superoxide levels in cerebral arteries.
Why the study?
Does introgressing the Brown Norway renin allele onto the Dahl salt-sensitive genetic background reduce vascular superoxide levels and increase SOD expression in cerebral arteries of rats?
Does introgressing the Brown Norway renin allele onto the Dahl salt-sensitive genetic background reduce vascular superoxide levels and increase SOD expression in cerebral arteries of rats?
Restoring normal renin-angiotensin system activity in Dahl salt-sensitive rats via genetic introgression lowers vascular superoxide levels and increases Cu/Zn SOD expression in cerebral arteries.
Answers are grounded in this paper and cite their sources.
Hypothesis-generating for renin effects on cerebral oxidative stress in salt-sensitive models; leaves open human translation.
BACKGROUND: Nitric oxide (NO)-dependent vasodilation is impaired in middle cerebral arteries (MCAs) from Dahl salt-sensitive (SS) rats that are fed normal salt (NS) diet, due to low plasma renin activity and chronic exposure to low plasma angiotensin II (ANG II) levels. NO-dependent vasodilator responses are rescued in MCAs from Ren1-BN congenic rats, which have a 2.0 Mbp portion of Brown Norway (BN) chromosome 13 containing the renin gene introgressed onto the Dahl SS genetic background. METHODS: Vascular superoxide levels were measured with dihydroethidium (DHE) fluorescence in basilar arteries from 10- to 14-week-old, male Dahl SS and Ren1-BN congenic rats that fed NS diet. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and xanthine oxidase (XO) activity were also measured in cerebral artery tissue homogenates. Expression of the superoxide dismutase (SOD) enzymes was evaluated via western blotting in cerebral arteries from the two rat strains. RESULTS: Superoxide levels were significantly higher in basilar arteries from Dahl SS rats compared to Ren1-BN congenic rats. NADPH oxidase and XO activity were similar between the two rat strains. Cu/Zn SOD expression was significantly higher in cerebral arteries from Ren1-BN congenic rats vs. those from Dahl SS rats. The expression of Mn-SOD was similar in cerebral arteries from both strains. CONCLUSIONS: These findings suggest that introgressing the BN renin allele onto the Dahl SS genetic background to restore normal activity of the renin-angiotensin system (RAS) protects NO-dependent vascular relaxation in cerebral arteries by increasing the expression of Cu/Zn SOD and lowering vascular superoxide levels.
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Durand et al. (2011) studied this question. Introgression of the Brown Norway renin allele (Ren1-BN congenic rats) vs. Dahl salt-sensitive (SS) rats was evaluated on Vascular superoxide levels and Cu/Zn SOD expression. Introgressing the Brown Norway renin allele onto the Dahl salt-sensitive background significantly increased Cu/Zn SOD expression and lowered vascular superoxide levels in cerebral arteries.
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