A Metabonomics Study of the Hepatotoxicants Galactosamine, Methylene Dianiline and Clofibrate in Rats*

Abstract: The efficacy of high-resolution 1H nuclear magnetic resonance (1H-NMR) spectroscopy-based metabonomics was studied in a model of rat liver toxicity. Hepatotoxicities were induced in male rats using methylene dianiline, clofibrate and galactosamine. Twenty-four-hr urine from days 1 to 5 after treatment were subjected to 1H-NMR evaluation of the biochemical effects. Blood were also taken at Days 2, 3 and 5 to examine biochemical changes associated with hepatotoxicities, and histopathological changes were evaluated at termination. Increases in liver enzymes were observed in animals treated with methylene dianiline or galactosamine, and histopathological analysis revealed changes associated with hepatobiliary damage and hepatocellular necrosis in methylene dianiline- and galactosamine-treated animals, respectively. Principal component analysis and statistical Spotfire analyses were used to visualize similarities and differences in urine biochemical profiles produced by 1H-NMR spectra. The biochemical effects of methylene dianiline and galactosamine were characterized by elevated levels of glucose, fructose, β-hydroxybutyrate, alanine, acetoacetate, lactate and creatine and decreased levels of hippurate, 2-oxoglutarate, citrate, succinate, trimethylamine-N-oxide, taurine and N-acetylglutamate in rat urine. Clofibrate treatment elevated the levels of N-methylnicotinamide and 3,4-dihydroxymandelate and decreased the levels of 2-oxoglutarate and N-acetylaspartate. This work shows that combinations of 1H-NMR and pattern recognition are powerful tools in the evaluation of the biochemical effects of xenobiotics in liver.