The level of hydrogen sulphide and antioxidant system in rat brain in homocysteine thiolactone-induced hyperhomocysteinemia and its correction
Hyperhomocysteinemia (HHC) is associated with neurovascular and neurodegenerative diseases. Disposal of homocysteine in the brain associated with the synthesis of H2S - neuromodulator, vasodilator, cytoprotector. It was established that under experimental hyperhomocysteinemia deficit H2S formed in the brain tissues is associated with decreased activity of H2S-synthesizing enzymes and with imbalance in ways of H2S utilization. The aim was to determine the effect of an isolated HHC on level H2S and indicators pro - / antioxidant systems in the rats brain under correction with vitamins B6, B9, B12 and esmin.
Materials and methods. Research conducted on 50 white laboratory male rats weighing 250-270 g. in accordance with the requirements of the Commission on bioethics, "the General ethical principles of animal experimentation" (Kyiv, 2001), "the European Convention for the protection of vertebrate animals used for research and other scientific purposes (Strasbourg, 1986). HHC aroused in 4 groups of rats by the administration of the thiolactone D,L-homocysteine (Sigma, USA) introgastrically in a dose 100 mg/kg during 28 days. H2S level, prooxidant and antioxidant enzymes activity were estimated in brain’s homogenates. The activity of cystathionine-β-synthase (EC 220.127.116.11) were measured in the incubation medium (0.67 mM pyridoxal phosphate, 3.3 mM L-cysteine, D, L-homocysteine 3.3 mM, 0.083 M Tris buffer, pH 8.5 at final concentrations) by H2S in growth. Homocysteine serum level was estimated by «Homocysteine EIA» (Axis-Shield, UK). Statistical analysis was conducted using the Student t-test, correlation analysis was performed by Pearson. Reliable considered the data at p<0.05.
Results. Introduction homocysteine thiolactone (100 mg / kg for 28 days) causes an increase in the basal level of homocysteine in the serum of 154%, which is accompanied by a decrease in the H2S level and activity of cystathionine-β-synthase in rat brain (53.0 and 34.1% ). In the HHC conditions violations in the H2S / cystathionine synthase-β-associated with increased activity of NADPH oxidase (on 76%), decreased activity of SOD, thioredoxin reductase, glutamate cysteine ligase and decreased glutathione content (on 38.6; 53.3; 50.3; 48.2%).
Administration of vitamins B6, B9, B12 or esmin reduces the level of homocysteine in the blood, reduced the deficit of H2S, and increased the activity of antioxidant enzymes in rat brain with HHC. But the composition of vitamins B6, B9, B12 with trace elemen*ts most effectively reduces homocysteine levels and corrects irregularities in H2S system and antioxidant system in the brain in conditions thiolactone-induced HHC.
Results. The composition of vitamins B6, B9, B12 with trace elements most effectively reduces homocysteine levels and corrects irregularities in H2S system and antioxidant system in the brain in conditions thiolactone-induced HHC. Thus, increase of H2S content in the brain by vitamins and trace elements can be an important strategy for the neuroprotection at the conditions of HHC.