The amount of enzyme that inhibited 50% of epinephrine auto-oxidation was defined as 1 U of SOD activity. The analysis
of CAT activity is based on measuring the decrease in hydrogen peroxide [32]. Catalase activity was determined by measuring the decrease in absorption at 240 nm in a reaction medium containing 50 mM PF-6463922 phosphate buffer saline (pH 7.2) and 0.3 M hydrogen peroxide. The enzyme activity was assayed spectrophotometrically at 240 nm. The activity of GPx is based on the NF-��B inhibitor consumption of NADPH in the reduction of oxidised glutathione [33]. The glutathione peroxidase activity was determined by the oxidation rate of NADPH in the presence of reduced glutathione and glutathione reductase. Sodium azide was added to inhibit catalase activity. The GPx activity was measured with a spectrophotometer at 340 nm. Total glutathione (GSH), a water soluble non-enzymatic antioxidant, [34] was measured as
described previously [35], in a reaction medium consisting of a solution of 300 mM phosphate buffer (Na2HPO4·1H2O) and a solution of dithionitrobenzoic acid (DTNB). The reaction products were read at 412 nm. The alkaline comet assay was carried out as described in [36], with minor modifications [37]. The liver tissue samples (200-250 mg) were placed in 0.5 mL of cold phosphate-buffered saline (PBS) and finely minced in order to obtain a cell suspension; the blood samples (50 μL) were placed in 5 μL of anti-coagulant (heparin sodium 25.000 UI- Liquemine®). Liver EGFR inhibitor and blood cell suspensions (5 μL) were embedded in 95 μL of 0.75% low melting point agarose (Gilco BRL) and spread on agarose-precoated microated microscope slides. After solidification, slides were placed in lysis buffer (2.5 M NaCl, 100 mM EDTA an 10 mM Tris, Cepharanthine pH 10.0), with freshly added 1% Triton X-100 (Sigma) and 10% DMSO for 48 h at 4°C. The slides were
subsequently incubated in freshly prepared alkaline buffer (300 mM NaOH and 1 mM EDTA, pH > 13) for 20 min, at 4°C. An electric current of 300 mA and 25 V (0.90 V/cm) was applied for 15 min to perform DNA electrophoresis. The slides were then neutralized (0.4 M Tris, pH 7.5), stained with silver and analyzed using microscope. Images of 100 randomly select cells (50 cells from each of two replicate slides) were analyzed from each animal. Cells were also visually scored according to tail size into five classes ranging from undamaged (0) to maximally damage (4), resulting in a single DNA damage score to each animal, and consequently to each studied group. Therefore, the damage index (DI) can range from 0 (completely undamaged, 100 cells × 0) to 400 (with maximum damage, 100 × 4). Damage frequency (%) was calculated based on the number of tailed versus tailless cells. The levels of nitrates and nitrites were measured by the reaction of the samples with Griess reagent.
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