Evaluation of the interaction of vanadium with glutathione in human blood components

Metallo-elements including Vanadium [V] have strong affinity for sulfhydryl [-SH] groups in biological molecules including Glutathione [GSH] in tissues. Because of this fact it was of interest to further investigate the interaction of Ammonium Vanadate [NH[4]VO[3]] with Glutathione as a biomarker of toxicity and the role of Glutathione in the detoxification and conjugation processes in whole blood components including plasma and cytosolic fraction. Effects of different concentrations of Ammonium Vanadate [NH[4]VO[3]] on the level of reduced Glutathione in whole blood components [Plasma and Cytosolic fraction] were examined. GSH depletion in plasma and cytosolic fraction was Ammonium Vanadate's concentration-dependent. Depleted GSH level was more pronounced with more incubation time period. These findings show that changes in the GSH status produced by Ammonium Vanadate could be due to either by adduct formation of Vanadium and glutathione i.e. [V-SG] or by increased production of oxidized Glutathione [2GSH +V[+5] - GSSG]. This change in GSH metabolic status provides some information regarding the mechanism of toxicity by Ammonium Vanadate and the protective role of glutathione

Amelioration of arsenic toxicity by L-Ascorbic acid in laboratory rat.

A study so as to confirm the protective effects of L-ascorbic acid against inorganic arsenic (As23) toxicity was made in male Wistar rats. Multiphase observations made on iAs concentration in target organs viz. liver and kidney, liver function, histopathological changes, ultrastructural alterations, lipid peroxidation, oxidative stress and iAs-DNA interaction strongly favoured its ameliorative effects. These effects could mainly be attributed to its antioxidative property. It offers help in regeneration of GSH and alpha-tocopherol. The chelaticn of iAs by ascorbic acid has also been hypothesized. Inhibition of DNA damage by ascorbic acid in liver and kidney appears to be the most significant part of this study On the basis of these results, we conclude that administration of L-ascorbic acid to arsenic affected population may prevent the occurrence of fatal human diseases.

Protective effect of ethanolic and water extracts of sea buckthorn (Hippophae rhamnoides L.) against the toxic effects of mustard gas.

Ethanolic extract of H. rhamnoides L. leaf (HL-EOH), water and ethanolic extract of H. rhamnoides fruit (HF-W and HF-EOH), and H. rhamnoides flavone from fruit (HR-flavone) were evaluated against percutaneously administered sulphur mustard (SM), a chemical warfare agent. The animals administered with SM (9.7, 19.3 and 38.7 mg/kg) died at various days depending upon the dose and there was a significant reduction in the body weight. The H. rhamnoides extracts (1 g/kg; 3 doses; po) significantly protected the lethality, with a protective index of 2.4, 1.7, 1.7 and 2.2 for HL-EOH, HF-W, HF-EOH and HR-flavone respectively. Reduced glutathione (GSH) and oxidized glutalthione (GSSG) levels were reduced, and malondialdehyde (MDA) was elevated after percutaneous administration of SM. Oral administration of HL-EOH and HR-flavone significantly protected the body weight loss. Recovery in the levels of GSH, GSSG and MDA were also observed following oral administration of HL-EOH and HR-flavone. All the extracts were non-toxic and the LD50 was more than 5 g/kg. The present study shows that percutaneous administration of SM induces oxidative stress and ethanolic extract of leaf of H. rhamnoides and H. rhamnoides flavone from fruit can significantly protect it.

Liver glutathione depletion after preservation and reperfusion in human liver transplantation

OBJETIVO: O estresse oxidativo é um importante mecanismo responsável pela disfunção dos enxertos após transplante de fígado (TF). Sabe-se que níveis baixos de Glutationa reduzida (GSH) deixam os enxertos vulneráveis aos danos de reperfusão. O objetivo deste estudo foi avaliar as concentrações de GSH e da Glutationa oxidada (GSSG), os danos hepatocelulares e a função em enxertos ótimos e subótimos após TF. MÉTODOS: Foram realizadas biópsias em 33 pacientes imediatamente antes do implante e duas horas após a reperfusão, permitindo a determinação do GSH, GSSG e o cálculo do índice de stress oxidativo (GSH/GSSG). Foram medidas as transaminases hepáticas e as atividades da Protrombina (TP) e do Fator V para avaliação dos danos hepatocelulares e da função do enxerto, respectivamente. O dano histopatológico foi avaliado através de um índice de cinco parâmetros. RESULTADOS: Houve uma diminuição nos níveis de GSH (p<0.01) 0.323 ± 0.062 ìmol/g to 0.095 ± 0.01 ìmol/g and 0.371 ± 0.052 ìmol/g to 0.183 ± 0.046 ìmol/g) e aumento nos níveis de GSSG (0.172 ± 0.038 ìmol/g to 0.278 ± 0.077 ìmol/g and 0.229 ± 0.048 ìmol/g to 0.356 ± 0.105 ìmol/g) (p<0.05). Houve diminuição do GSH/GSSG (2.23 ± 0.31 to 0.482 ± 0.042 and 2.47 ± 0.32 to 0.593 ± 0.068). Nenhuma diferença entre os grupos ótimo e subótimo foi vista após duas horas de reperfusão. Os escores de danos histopatológicos foram maiores no grupo subótimo (6.46 ± 0.4 vs. 5.39 ± 1.1) (p<0.05) e mostraram correlação com o TP e fator V no grupo Ótimo (p<0.05). A análise multivariada apontou a esteatose como um fator de risco independente para a ocorrência de danos histopatológicos (p<0.05). CONCLUSÃO: Houve uma significativa depleção de GSH e formação de GSSG após a preservação em solução devido a um intenso estresse oxidativo nos enxertos ótimos e subótimos, porém estes níveis não se correlacionaram com a viabilidade dos enxertos.

Antioxidant responses of cortex neurons to iron loading

Brain cells have a highly active oxidative metabolism, yet they contain only low to moderate superoxide dismutase and catalase activities. Thus, their antioxidant defenses rely mainly on cellular reduced glutathione levels. In this work, in cortical neurons we characterized viability and changes in reduced and oxidized glutathione levels in response to a protocol of iron accumulation. We found that massive death occurred after 2 days in culture with 10 mM Fe. Surviving cells developed an adaptative response that included increased synthesis of GSH and the maintenance of a glutathione-based reduction potential. These results highlight the fundamental role of glutathione homeostasis in the antioxidant response and provide novel insights into the adaptative mechanisms of neurons subjected to progressive iron loads.

In vivo and in vitro influence of selenium on DNA/RNA synthesis in spleen and lymphocytes in culture--possible mediation of changes in GSH/GSSG ratio.

Effect of superanutritional levels of selenium (Se) as sodium selenite (0.5 and 1.5 ppm) given orally to Balb/c mice for one and two weeks was observed on the rate of DNA/RNA synthesis, levels of reduced as well as oxidized glutathione (GSH and GSSG) and glutathione peroxidase (GSH-Px)/glutathione-S-transferase (GSH-S-transferase) activities in spleen. Similar effect of three different concentrations of Se (10(-7), 10(-5) and 10(-3) M) in culture media was also observed on the rate of DNA/RNA synthesis in proliferating lymphocytes taken from mice spleen. The results of the present study indicated that with increasing concentration and duration of Se treatment in vivo and in vitro, a marked inhibition of the rate of DNA/RNA synthesis was observed. Levels of total glutathione and GSSG in spleen were elevated significantly only after two weeks in 1.5 ppm treatments. Glutathione peroxidase activities in spleen decreased (p < 0.05) in 1.5 ppm group at one week and in 0.5 ppm group at two week treatment. At higher Se treatment, the activity recovered towards control. However, GSH-S-transferase in spleen remained unchanged at all treatment intervals. The results indicated that changes in glutathione system by increasing Se concentration might account for inhibition of rate of DNA/RNA synthesis.