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  • Meeting abstract
  • Open Access

Role of NADPH oxidase in the vascular reactivity and superoxide generation in the intrauterine undernourished rats: involvement of the renin–angiotensin system

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Critical Care20037 (Suppl 3) :P126

  • Published:


  • NADPH Oxidase
  • Xanthine Oxidase
  • Apocynin
  • Xanthine Oxidase Inhibitor
  • NADPH Oxidase Inhibition

We previously reported that intrauterine undernutrition increased the oxidative stress by decreasing superoxide dismutase activity. In the present study, we tested whether NADPH oxidase, xanthine oxidase, cyclooxygenase or nitric oxide synthase are responsible for the increased O2- generation observed in rats submitted to intrauterine undernutrition. In addition, we investigated the effect of angiotensin II (Ang II) on O2- production via activation of NADPH oxidase. Treatment of mesenteric arterioles with the xanthine oxidase inhibitor oxypurinol, the nitric oxide synthase inhibitor L-NAME or the cyclooxygenase inhibitor diclofenac did not significantly change superoxide production. These vascular sources of superoxide were thus not responsible for the increased superoxide concentration. In contrast, treatment with the NADPH oxidase inhibitor apocynin significantly decreased superoxide generation (10.3 ± 3.9 vs 22.35 ± 5.69, P < 0.05) and improved vascular function. On the other hand, intrauterine undernutrition did not alter the gene expression for p22phox and gp91phox. The fact that the local Ang II concentration was increased and the attenuation of oxidative stress by blocking the AT1 receptor with losatan (9.9 ± 1.9 vs 22.35 ± 5.69, P < 0.05) led us to suggest that Ang II induces O2- generation in intrauterine undernourished rats. Our study shows that NADPH oxidase inhibition attenuated superoxide anion generation and ameliorated vascular function in rats submitted to intrauterine undernutrition. Although it is not clear which mechanisms are responsible for the increase in NADPH oxidase activity, a role for Ang II-mediated superoxide production via activation of NADPH oxidase is suggested.

Authors’ Affiliations

Laboratory of Hypertension, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
Laboratory of Nephorology, UNIFESP, São Paulo, SP, Brazil


© BioMed Central Ltd 2003