Kidney Res Clin Pract.  2014 Mar;33(1):19-25.

Effects of oxidative stress on endothelial modulation of contractions in aorta from renal hypertensive rats

• Choi S
• Shin HR
• Kim SH
• Lee MJ
• Jun JY
• Kim HL
• Chung JH
• Yeum CH

Abstract

BACKGROUND
Endothelial dysfunction is linked to exaggerated production of superoxide anions. This study was conducted to examine the effects of oxidative stress on endothelial modulation of contractions in chronic two-kidney, one-clip (2K1C) renal hypertensive rats.
METHODS
The 2K1C hypertension was induced by clipping the left renal artery; age-matched rats receiving sham treatment served as controls. Thoracic aortae were isolated and mounted in tissue baths for measurement of isometric tension.
RESULTS
Norepinephrine-induced contraction was augmented by the removal of the endothelium, which was more pronounced in sham rats than in 2K1C rats. Nomega-nitro-L-arginine methyl ester, an inhibitor of nitric oxide production, had a similar augmenting effect. Vitamin C inhibited the contraction in aortic rings with intact endothelium from 2K1C rats but not from sham rats. The contraction was also suppressed by treatment with diphenyleneiodonium or apocynin, inhibitors of nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate (NADH/NADPH) oxidase, in the aortae with intact endothelium from 2K1C rats but not in those from sham rats. Superoxide anions generated by xanthine oxidase/hypoxanthine enhanced the contraction in the aortae with intact endothelium from sham rats, but had no effect in 2K1C rats. Enhanced contractile responses to norepinephrine by xanthine oxidase/hypoxanthine in sham rats were reversed by vitamin C.
CONCLUSION
These results suggest that the effect on endothelial modulation of endothelium-derived nitric oxide is impaired in 2K1C hypertension. The impairment is, at least in part, related to increased production of superoxide anions by NADH/NADPH oxidase.

Keyword

Endothelium; Renal hypertension; Superoxide; Oxidative stress

MeSH Terms

Adenine
Animals
Aorta*
Aorta, Thoracic
Ascorbic Acid
Baths
Endothelium
Hypertension
Hypertension, Renal
Niacinamide
Nitric Oxide
Norepinephrine
Oxidative Stress*
Oxidoreductases
Placebos
Rats*
Renal Artery
Superoxides
Xanthine
Adenine
Ascorbic Acid
Niacinamide
Nitric Oxide
Norepinephrine
Oxidoreductases
Placebos
Superoxides
Xanthine