Oxidative stress markers in the brain of a glaucoma model

S.M. FERREIRA; S.F. LERNER; C.G. REIDES; S.F. LLESUY

Santiago de Chile

Congreso; Free Radicals and antioxidants; 2009

The aim of the present study was to establish the antioxidant status in brain homogenates of an experimental glaucoma model. Wistar rats (n= 12) weighing 250-300 g were operated under a microscope by cauterized two of the epischeral veins (GG) and another  sham procedure group (n= 12) (GC). In order to assess the occurrence of oxidative stress the following markers were evaluated in brain homogenates at seven days after the surgery: spontaneous chemiluminescence (QL), the activities of antioxidant enzymes: superoxide dismutase (SOD) , catalase (CAT) and glutathione peroxidase (GPX),  protein carbonylation (PC), total antioxidant capacity (TRAP), ascorbic acid and nitrite concentrations. QL in GG was  690 ± 41 cpm/ mg protein (GC: 432 ± 29 cpm/ mg protein  *p< 0,001). PC in glaucoma  rats was 2,84  ± 0,216 nmoles/ mg protein (GC: 1,46 ± 0,27 nmoles/ mg protein *p< 0,001). SOD activity in GG was 3,98 ± 0,43 U/ mg protein  (GC 2,51 ± 0,28 U/ mg protein *p< 0,05). GPX activity in glaucoma rats  was  0,067 ± 0,008 U/ mg protein.min (GC 0,042 ± 0,003 U/ mg protein.min *p< 0,05). No significant changes were found in CAT. TRAP levels were 50% decreased in GG (GC 153 ± 18 mM*p< 0,001) . Nitrite concentration was 5,30 ± 0,25 mM for GG (GC 4,41 ± 0,24 mM *p< 0,05). Ascorbic acid concentration was 275 ± 22 mM for GG (GC 67 ± 26 mM *p< 0,001). Reactive oxygen and nitrogen species were increased in glaucoma, this could be evidenced by the increased in the chemiluminescence, protein carbonylation and nitrite concentration. The decrease in antioxidants and a compensatory up-regulation of SOD and glutathione peroxidase activity may be a consecuence of an increase in