Most cited article - PubMed ID 17182211
Determination of reduced and oxidized glutathione in biological samples using liquid chromatography with fluorimetric detection
Mitochondria play an essential role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Previously, we found that succinate-activated respiration was the most affected mitochondrial parameter in mice with mild NAFLD. In this study, we focused on the role of succinate dehydrogenase (SDH) in NAFLD pathogenesis. To induce the progression of NAFLD to nonalcoholic steatohepatitis (NASH), C57BL/6J mice were fed a Western-style diet (WD) or control diet for 30 weeks. NAFLD severity was evaluated histologically and the expression of selected proteins and genes was assessed. Mitochondrial respiration was measured by high-resolution respirometry. Liver redox status was assessed using glutathione, malondialdehyde, and mitochondrial production of reactive oxygen species (ROS). Metabolomic analysis was performed by GC/MS. WD consumption for 30 weeks led to reduced succinate-activated respiration. We also observed decreased SDH activity, decreased expression of the SDH activator sirtuin 3, decreased gene expression of SDH subunits, and increased levels of hepatic succinate, an important signaling molecule. Succinate receptor 1 (SUCNR1) gene and protein expression were reduced in the livers of WD-fed mice. We did not observe signs of oxidative damage compared to the control group. The changes observed in WD-fed mice appear to be adaptive to prevent mitochondrial respiratory chain overload and massive ROS production.
- Keywords
- mitochondria, nonalcoholic fatty liver disease, oxidative phosphorylation, respirometry, succinate, succinate dehydrogenase,
- MeSH
- Apoptosis MeSH
- Biomarkers MeSH
- Cell Respiration MeSH
- Fibrosis MeSH
- Mitochondria, Liver metabolism MeSH
- Succinic Acid metabolism MeSH
- Metabolome MeSH
- Metabolomics methods MeSH
- Disease Models, Animal MeSH
- Mice MeSH
- Disease Susceptibility MeSH
- Non-alcoholic Fatty Liver Disease etiology metabolism pathology MeSH
- Oxidation-Reduction * MeSH
- Oxidative Stress * MeSH
- Succinate Dehydrogenase metabolism MeSH
- Diet, Western * MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Biomarkers MeSH
- Succinic Acid MeSH
- Succinate Dehydrogenase MeSH
Maladaptation of mitochondrial oxidative flux seems to be a considerable feature of nonalcoholic fatty liver disease (NAFLD). The aim of this work was to induce NAFLD in mice fed a Western-style diet (WD) and to evaluate liver mitochondrial functions. Experiments were performed on male C57BL/6J mice fed with a control diet or a WD for 24 weeks. Histological changes in liver and adipose tissue as well as hepatic expression of fibrotic and inflammatory genes and proteins were evaluated. The mitochondrial respiration was assessed by high-resolution respirometry. Oxidative stress was evaluated by measuring lipoperoxidation, glutathione, and reactive oxygen species level. Feeding mice a WD induced adipose tissue inflammation and massive liver steatosis accompanied by mild inflammation and fibrosis. We found decreased succinate-activated mitochondrial respiration and decreased succinate dehydrogenase (SDH) activity in the mice fed a WD. The oxidative flux with other substrates was not affected. We observed increased ketogenic capacity, but no impact on the capacity for fatty acid oxidation. We did not confirm the presence of oxidative stress. Mitochondria in this stage of the disease are adapted to increased substrate flux. However, inhibition of SDH can lead to the accumulation of succinate, an important signaling molecule associated with inflammation, fibrosis, and carcinogenesis.
- Keywords
- mitochondria, nonalcoholic fatty liver disease, oxidative phosphorylation, respirometry,
- MeSH
- Diet, High-Fat adverse effects MeSH
- Glutathione metabolism MeSH
- Mitochondria, Liver metabolism MeSH
- Liver metabolism pathology MeSH
- Mice, Inbred C57BL MeSH
- Mice MeSH
- Non-alcoholic Fatty Liver Disease etiology metabolism MeSH
- Lipid Peroxidation * MeSH
- Succinate Dehydrogenase metabolism MeSH
- Adipose Tissue metabolism pathology MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Glutathione MeSH
- Succinate Dehydrogenase MeSH
Non-alcoholic fatty liver disease (NAFLD) is the most common chronic condition of the liver in the western world. There is only little evidence about altered sensitivity of steatotic liver to acute toxic injury. The aim of this project was to test whether hepatic steatosis sensitizes rat liver to acute toxic injury induced by thioacetamide (TAA). Male Sprague-Dawley rats were fed ad libitum a standard pelleted diet (ST-1, 10% energy fat) and high-fat gelled diet (HFGD, 71% energy fat) for 6 weeks and then TAA was applied intraperitoneally in one dose of 100 mg/kg. Animals were sacrificed in 24-, 48- and 72-h interval after TAA administration. We assessed the serum biochemistry, the hepatic reduced glutathione, thiobarbituric acid reactive substances, cytokine concentration, the respiration of isolated liver mitochondria and histopathological samples (H+E, Sudan III, bromodeoxyuridine [BrdU] incorporation). Activities of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase and concentration of serum bilirubin were significantly higher in HFGD groups after application of TAA, compared to ST-1. There were no differences in activities of respiratory complexes I and II. Serum tumour necrosis factor alpha at 24 and 48 h, liver tissue interleukin-6 at 72 h and transforming growth factor β1 at 24 and 48 h were elevated in TAA-administrated rats fed with HFGD, but not ST-1. TAA-induced centrilobular necrosis and subsequent regenerative response of the liver were higher in HFGD-fed rats in comparison with ST-1. Liver affected by NAFLD, compared to non-steatotic liver, is more sensitive to toxic effect of TAA.
- MeSH
- Cholesterol metabolism MeSH
- Cytokines blood MeSH
- Dietary Fats adverse effects MeSH
- Liver drug effects metabolism pathology MeSH
- Carcinogens toxicity MeSH
- Rats MeSH
- Thiobarbituric Acid Reactive Substances metabolism MeSH
- Disease Models, Animal MeSH
- Non-alcoholic Fatty Liver Disease MeSH
- Rats, Sprague-Dawley MeSH
- Cell Proliferation drug effects MeSH
- Electron Transport Complex I drug effects physiology MeSH
- Electron Transport Complex II drug effects physiology MeSH
- Thioacetamide toxicity MeSH
- Triglycerides metabolism MeSH
- Fatty Liver blood chemically induced pathology MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH
- Names of Substances
- Cholesterol MeSH
- Cytokines MeSH
- Dietary Fats MeSH
- Carcinogens MeSH
- Thiobarbituric Acid Reactive Substances MeSH
- Electron Transport Complex I MeSH
- Electron Transport Complex II MeSH
- respiratory complex II MeSH Browser
- Thioacetamide MeSH
- Triglycerides MeSH
Vitamin C (ascorbic acid, ascorbate, AA) is a water soluble organic compound that participates in many biological processes. The main aim of this paper was to utilize two electrochemical detectors (amperometric - Coulouchem III and coulometric - CoulArray) coupled with flow injection analysis for the detection of ascorbic acid. Primarily, we optimized the experimental conditions. The optimized conditions were as follows: detector potential 100 mV, temperature 25 °C, mobile phase 0.09% TFA:ACN, 3:97 (v/v) and flow rate 0.13 mL·min-1. The tangents of the calibration curves were 0.3788 for the coulometric method and 0.0136 for the amperometric one. The tangent of the calibration curve measured by the coulometric detector was almost 30 times higher than the tangent measured by the amperometric detector. Consequently, we coupled a CoulArray electrochemical detector with high performance liquid chromatography and estimated the detection limit for AA as 90 nM (450 fmol per 5 μL injection). The method was used for the determination of vitamin C in a pharmaceutical preparations (98 ± 2 mg per tablet), in oranges (Citrus aurantium) (varied from 30 to 56 mg/100 g fresh weight), in apples (Malus sp.) (varied from 11 to 19 mg/100 g fresh weight), and in human blood serum (varied from 38 to 78 μM). The recoveries were also determined.
