NMR and pattern recognition studies on liver extracts and intact livers from rats treated with α-naphthylisothiocyanate

• Published in: Biochemical pharmacology 2002-07, Vol.64 (1), p.67-77
• Main Authors: Waters, Nigel J, Holmes, Elaine, Waterfield, Catherine J, Farrant, R.Duncan, Nicholson, Jeremy K
• Format: Article
• Language: English
• Subjects: 1-Naphthylisothiocyanate - toxicity; Analysis; Animals; Aqueous extract; Biological and medical sciences; Chloroform/methanol extract; General pharmacology; Han–Wistar rat; Liver; Liver - chemistry; Liver - drug effects; Liver Extracts - chemistry; Magic angle spinning; Magnetic Resonance Spectroscopy - methods; Male; MAS [formula omitted] NMR spectroscopy; Mass Spectrometry; Medical sciences; Metabonomics; Pattern Recognition, Automated; Pharmacology. Drug treatments; Rats; Rats, Wistar; α-Naphthylisothiocyanate
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/S0006-2952(02)01016-X

The metabolite profiles from livers of toxin-treated rats were investigated using high resolution 1 H NMR spectroscopy of aqueous (acetonitrile/water), lipidic (chloroform/methanol) extracts and magic angle spinning (MAS)-NMR spectroscopy of intact tissue. Rats were treated with the model cholestatic hepatotoxin, α-naphthylisothiocyanate (ANIT, 150 mg/kg) and NMR spectra of liver were analysed using principal components analysis (PCA) to extract novel toxicity biomarker information. 1 H NMR spectra of control aqueous extracts showed signals from a range of organic acids and bases, amino acids, sugars, and glycogen. Chloroform/methanol extracts showed signals from a range of saturated and unsaturated triglycerides, phospholipids and cholesterol. The MAS 1 H NMR spectra of livers showed a composite of signals found in both aqueous and lipophilic extracts. Following ANIT treatment, 1 H NMR-PCA of aqueous extracts indicated a progressive reduction in glucose and glycogen, together with increases in bile acid, choline, and phosphocholine signals. 1 H NMR-PCA of chloroform/methanol extracts showed elevated triglyceride levels. The 1 H MAS-NMR-PCA analysis allowed direct detection of all of the ANIT-induced tissue perturbations revealed by 1 H NMR of extracts, enabling metabolic characterisation of the lesion, which included steatosis, bile duct obstruction and altered glucose/glycogen metabolism. MAS-NMR spectroscopy requires minimal sample preparation and, unlike 1 H NMR spectroscopy of tissue extracts, does not discriminate metabolites based on their solubility in a particular solvent and so this is a particularly useful exploratory tool in biochemical toxicology.