Attempts have made to characterize the antioxidant potential of the early phase of bronchial asthma. An experimental model trying to mimic allergic bronchial asthma was immunologically induced with ovalbumin (OA) in guinea pigs which were then treated with a NO donor (ammonium salt of N- nitrosophenyl-N-hydroxilamine) at a concentration of 0,1 mg/Kg (1/400 of DL50) for 2 weeks. The animals were killed afterwards, for assessing the presence of cellular oxidative stress and free radicals (FR). The changes in the activity of superoxide-dismutase (SOD), glutathione-peroxidase (GPx), reduced glutathione (GSH) and malon-dialdehide (MDA), were followed in the heparinized blood of guinea pigs series (5-6 animals in series): L1 = nebulized with OA; L2 = hypersensitized with OA; L3 = hypersensitized with OA and treated intraperitoneal for 2 weeks with NO donor; L4 = controls, healthy guinea pigs.

The final data have revealed: The increased activity of SOD at series L3 compared to series L1 (+120.79 %) and to series L2 (+69.95 %) becoming closer to the activity of the control series; the increased activity of GPx at series L3, compared to series L1 (+2.48 %), to series L2 (+24.77 %) and to series L4 (+8.64 %); the decreased level of GSH at series L3, compared to series L2 (-22.18 %) and to series L1 (-15.83 %), but with an increased level compared to series L4 (+ 36.85 %); the decreased concentration of MDA at series L3 compared to series L1 (-6.52 %), to series L2 (-17,64 %) and to series L4 (-9.40 %), all these proving a lower level of the lipid peroxides and damaging free radicals. The positive effect of the NO- donor, with the above specific concentration, is due to the stimulation of the synthesis of the oxidative stress biomarkers which have an important antioxidant rol.