1H NMR-based metabonomics approach in a rat model of acute liver injury and regeneration induced by CCl4 administration

Abstract

The administration of carbon tetrachloride (CCl4) has been established as a model of toxin-induced acute and chronic liver injury. In the present study, we investigate the progression of the biochemical response to acute CCl4-induced liver injury, capturing metabolic variations during both toxic insult and regeneration using NMR-based metabonomic analysis of liver tissue and plasma.A single dose of CCl4 (1mL/kg BW) was intraperitoneally administered to male Wister rats sacrificed every 12h up to 72h post treatment, while healthy animals served as controls. Acquired 1H NMR spectra of liver tissue extracts and plasma samples were explored with multivariate analysis and the resulted models were correlated with conventional biochemical and histopathological indices of toxicity for monitoring the progression of experimental injury.The metabonomic analysis resulted in discrimination between the subjects under toxic insult (up to 36h) and those at the regenerative phase (peaked at 48h). At 72h normalization of liver's pathology similar to the controls group was apparent. Principal component analysis (PCA) trajectories highlighted the time points of the greater degree of toxic insult and the regenerative state.A number of metabolites such as glucose, lactate, choline, formate exhibited variations suggesting CCl4 induced impairment in essential biochemical pathways as energy metabolism, lipid biosynthesis and transmethylation reactions. The latter provides new evidence of B12 and folate pathways deficiency, indicative of new mechanistic implications possibly by direct inhibition of B12 dependent enzymes by the chlorinated radicals of CCl4 metabolism.