Analysis of time-related metabolic fluctuations induced by ethionine in the rat.
ABSTRACT The time-course of metabolic events following response to a model hepatotoxin ethionine (800 mg/kg) was investigated over a 7 day period in rats using high-resolution (1)H NMR spectroscopic analysis of urine and multivariate statistics. Complementary information was obtained by multivariate analysis of (1)H MAS NMR spectra of intact liver and by conventional histopathology and clinical chemistry of blood plasma. (1)H MAS NMR spectra of liver showed toxin-induced lipidosis 24 h postdose consistent with the steatosis observed by histopathology, while hypertaurinuria was suggestive of liver injury. Early biochemical changes in urine included elevation of guanidinoacetate, suggesting impaired methylation reactions. Urinary increases in 5-oxoproline and glycine suggested disruption of the gamma-glutamyl cycle. Signs of ATP depletion together with impairment of the energy metabolism were given from the decreased levels in tricarboxylic acid cycle intermediates, the appearance of ketone bodies in urine, the depletion of hepatic glucose and glycogen, and also hypoglycemia. The observed increase in nicotinuric acid in urine could be an indication of an increase in NAD catabolism, a possible consequence of ATP depletion. Effects on the gut microbiota were suggested by the observed urinary reductions in the microbial metabolites 3-/4-hydroxyphenyl propionic acid, dimethylamine, and tryptamine. At later stages of toxicity, there was evidence of kidney damage, as indicated by the tubular damage observed by histopathology, supported by increased urinary excretion of lactic acid, amino acids, and glucose. These studies have given new insights into mechanisms of ethionine-induced toxicity and show the value of multisystem level data integration in the understanding of experimental models of toxicity or disease.
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ABSTRACT: The aim of this work was to identify mechanisms and potential biomarkers for predicting the development and progression of aflatoxin B1 (AFB1)-induced acute hepatotoxicity. In this study, microarray analysis and metabolites profiles were used to identify shifts in gene expression and metabolite levels associated with the affected physiological processes of rats treated with AFB1. Histopathological examinations and serum biochemical analysis were simultaneously performed; the results indicated that hepatotoxicity occurred in higher dosage groups. However, gene expression analysis and metabolite profiles are more sensitive than general toxicity studies for detecting AFB1-induced acute hepatotoxicity as the patterns of low-dose AFB1-treated rats in these two technique platforms were more similar to the rats in higher dosage groups than to the control rats. Integrated analysis of the results from general toxicity studies, transcriptomics and metabonomics profiles suggested that p53 signaling pathway induced by oxidative damage was the crucial step in AFB1-induced liver hepatotoxicity, whereas gluconeogenesis and lipid metabolism disorder were found to be the major metabolic effects after acute AFB1 exposure. The genes and metabolites significantly affected in common in rat liver or serum of three doses AFB1 treatments served as potential biomarkers for detecting AFB1-induced acute hepatotoxicity.Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 02/2013; · 2.99 Impact Factor
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ABSTRACT: Erythromycin estolate (EE), a macrolide antibiotic, has caused hepatotoxicity both in human and experimental animals. The objective of this study was to integrate general toxicology, transcriptomics, and metabonomics approaches to determine the mechanisms of EE-induced liver injury. Histopathological examinations unveiled dose-dependent hydropicdegenerationof hepatocytes after EE administration. Further biochemical analysis of treated rats confirmed that cholestasis and oxidative stress were induced by EE treatments. Microarray analysis of the livers from EE-treated rats showed that differentially expressed genes were enriched in the ABC transporters, cell cycle, and p53 signaling pathways. Metabonomics analysis revealed that EE exposure could lead to disturbances in energy metabolism, amino acid metabolism, lipid metabolism, and nucleotide metabolism, which may be attributable to EE toxicological effects on the liver through oxidative stress. 5-oxoproline may be used as a biomarker of EE-induced liver injury. More importantly, the integrated analysis of transcriptomics and metabonomics datasets demonstrated that the induction of ABC transporters pathway severed as an anti-cholestatic adaptive mechanism in EE-induced cholestasis. In addition, EE-induced liver injury was also related to alteration in glycogen and sucrose metabolism, arachidonic acid metabolism, and linoleic acid metabolism pathways.Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 01/2014; · 2.99 Impact Factor
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ABSTRACT: Heavy metals that are harmful to humans include arsenic, cadmium, chromium, lead, mercury, and nickel. Some metals or their related compounds may even cause cancer. However, the mechanism underlying heavy metal-induced cancer remains unclear. Increasing data show a link between heavy metal exposure and aberrant changes in both genetic and epigenetic factors via non-targeted multiple toxicogenomic technologies of the transcriptome, proteome, metabolome, and epigenome. These modifications due to heavy metal exposure might provide a better understanding of environmental disorders. Such informative changes following heavy metal exposure might also be useful for screening of biomarker-monitored exposure to environmental pollutants and/or predicting the risk of disease. We summarize advances in high-throughput toxicogenomic-based technologies and studies related to exposure to individual heavy metal and/or mixtures and propose the underlying mechanism of action and toxicant signatures. Integrative multi-level expression analysis of the toxicity of heavy metals via system toxicology-based methodologies combined with statistical and computational tools might clarify the biological pathways involved in carcinogenic processes. Although standard in vitro and in vivo endpoint testing of mutagenicity and carcinogenicity are considered a complementary approach linked to disease, we also suggest that further evaluation of prominent biomarkers reflecting effects, responses, and disease susceptibility might be diagnostic. Furthermore, we discuss challenges in toxicogenomic applications for toxicological studies of metal mixtures and epidemiological research. Taken together, this review presents toxicogenomic data that will be useful for improvement of the knowledge of carcinogenesis and the development of better strategies for health risk assessment.International journal of hygiene and environmental health 03/2013; · 2.64 Impact Factor