ABSTRACT
Acetaminophen overdose is the most often cause of acute liver injury. The toxic mechanism is linked to formation of an active metabolite that reacts with glutathione generating acetaminophen-glutathione conjugate (APAP-SG). This compound has been recognized to be non-toxic generally. Our preliminary results showed, however, that APAP-SG could possess a toxic effect too. Therefore, the aim of our study was to prepare, purify and to test possible toxicity of APAP-SG. We prepared APAP-SG using organic synthesis. The conjugate was purified by preparative HPLC and its structure was confirmed using mass spectrometry. Final purity of APAP-SG was >98 %. We estimated a toxic effect of APAP-SG in isolated rat liver mitochondria using a fluorescent ROS probe. We assessed ROS production in presence of complex I or complex II substrates. The increase of ROS-dependent fluorescence in presence of glutamate/malate was 104 ± 13 % and 130 ± 10 % in 1 mM and 5 mM APAP-SG, respectively, in comparison with controls. ROS production related to presence of complex II substrate was enhanced 4-times in APAP-SG (5 mM) treated mitochondria (compared to controls). We conclude, we proved our hypothesis that APAP-SG conjugate is able to induce a mitochondrial impairment leading to enhanced ROS production.
Subject(s)
Acetaminophen/analogs & derivatives , Mitochondria, Liver/drug effects , Oxidative Stress , Acetaminophen/chemical synthesis , Acetaminophen/isolation & purification , Acetaminophen/toxicity , Animals , Chemical and Drug Induced Liver Injury/metabolism , Chemical and Drug Induced Liver Injury/pathology , Disease Models, Animal , Dose-Response Relationship, Drug , Glutamic Acid/metabolism , Liver/metabolism , Malates/metabolism , Male , Mitochondria, Liver/metabolism , Rats , Rats, Wistar , Reactive Oxygen Species/metabolismABSTRACT
Non-alcoholic fatty liver disease (NAFLD) is an important cause of liver-related morbidity and mortality. The aim of this work was to establish and characterize a nutritional model of NAFLD in rats. Wistar or Sprague-Dawley male rats were fed ad libitum a standard diet (ST-1, 10 % kcal fat), a medium-fat gelled diet (MFGD, 35 % kcal fat) and a high-fat gelled diet (HFGD, 71 % kcal fat) for 3 or 6 weeks. We examined the serum biochemistry, the hepatic malondialdehyde, reduced glutathione (GSH) and cytokine concentration, the respiration of liver mitochondria, the expression of uncoupling protein-2 (UCP-2) mRNA in the liver and histopathological samples. Feeding with MFGD and HFGD in Wistar rats or HFGD in Sprague-Dawley rats induced small-droplet or mixed steatosis without focal inflammation or necrosis. Compared to the standard diet, there were no significant differences in serum biochemical parameters, except lower concentrations of triacylglycerols in HFGD and MFGD groups. Liver GSH was decreased in rats fed HFGD for 3 weeks in comparison with ST-1. Higher hepatic malondialdehyde was found in both strains of rats fed HFGD for 6 weeks and in Sprague-Dawley groups using MFGD or HFGD for 3 weeks vs. the standard diet. Expression of UCP-2 mRNA was increased in Wistar rats fed MFGD and HFGD for 6 weeks and in Sprague-Dawley rats using HFGD for 6 weeks compared to ST-1. The present study showed that male Wistar and Sprague-Dawley rats fed by HFGD developed comparable simple steatosis without signs of progression to non-alcoholic steatohepatitis under our experimental conditions.
Subject(s)
Diet/adverse effects , Dietary Fats/adverse effects , Fatty Liver/etiology , Animals , Disease Models, Animal , Glutathione/blood , Ion Channels/biosynthesis , Liver/chemistry , Male , Malondialdehyde/metabolism , Mitochondrial Proteins/biosynthesis , Non-alcoholic Fatty Liver Disease , Rats , Rats, Sprague-Dawley , Rats, Wistar , Triglycerides/blood , Uncoupling Protein 2ABSTRACT
Iron humate produced as a waste by-product during an industrial manufacture of humic substances from low-rank brown coals was tested as a sorbent for the removal of metal cations--Cd (II), Cu (II), Co (II), Ni (II), Zn (II), TI (I), Eu (III), Cr (III)--as well as hexavalent chromium from waters. The Langmuir-type isotherms were used to describe the metal sorption; the respective equations may be derived and interpreted on the basis of a concept of surface-complexation reactions. Parameters of the sorption isotherms were estimated from experimental dependencies measured in a batch arrangement. The sorption capacities ranged from 0.024 mmol g(-1)for Co (II) to 0.324 mmol g(-1)for Tl(I). The metal uptake was affected by the presence of complexing agents (EDTA, salicylate, citrate), but this effect depends strongly on pH and the kind of complexing agent. The sorption of Cu (II) ions was suppressed in the presence of EDTA in an almost whole examined pH range (ca. 1-6.5) and in the presence of citrate at higher pH values (above pH 4). In the presence of salicylate, on the other hand, a slight sorption enhancement was observed. The metal sorption was suppressed also in the presence of anionic surfactant (sodium dodecylsulfate). Both in the presence as well as in the absence of complexing agents, the metal sorption showed a strong dependence on pH--the sorption was reduced considerably at low pH values below ca. 2. A typical working range for iron humate as a sorbent is ca. pH 3-5, where it exhibits a high buffering capacity, a sufficient stability and metal-binding capability.
