To anticipate the impact of antioxidant use on lipid peroxidation products, free oxygen radical scavengers, blood pressure (BP), proteinuria and neonatal outcome (as seen in percentage survival, litter birth weight) in a rat model of pre-eclampsia induced by NG-nitro-L-arginine-methyl-ester (L-NAME), an inhibitor of nitric oxide synthase (NOS).
Female adult non-pregnant Sprague-Dawley rats (n=40) with timed pregnancies were allocated into four groups according to medication they received on day 17 to term. Rats were randomised into a sham-treated group (group I, n=10) and groups treated with L-NAME, 50 mg/day i.p., only (group II, n=10), L-NAME + quercetine, 10mg/kg i.p. (group III, n=10) and L-NAME + glutathione, 60 mg/kg i.p. (group IV, n=10). Blood levels of superoxide dismutase (SOD), catalase (CAT) and malonyldialdehyde (MDA) were assessed on day 22 of gestation. Intracardiac blood sampling and hysterotomy were performed on day 22 of gestation. Mean systolic BP (measured with a tail-cuff device), level of proteinuria, total urine output, pups birth weight and percentages of live and of dead pups were recorded.
Mean systolic BP and SOD, CAT and MDA levels were higher in rats infused with L-NAME than in the sham-treated group. In group IV, SOD levels were lower than in group II (P <0.001). A linear positive correlation between BPs on day 20 and SOD levels (rp=0.39) was recorded, as were negative correlations between level of proteinuria and SOD levels (rp=-0.39) and between CAT and MDA levels (rp=-0.39). Birth weights were higher in the sham-treated group than in the other groups (P <0.001). Pups of hypertensive gravid rats treated with antioxidants had better survival rates than those of rats in group II and the sham-treated group (Chi-square=15.9, d.f.: 3, P <0.01).However, no correlation was detected between higher pup mortality rate and birth weight of pups.
In this rat model of pre-eclampsia, adverse outcomes, such as proteinuria and high neonatal death rate, are reversed by exogenous antioxidant use, even though no significant improvement is detected in terms of BP and birth weight of pups.