Toxicological effect of thallium in mice by NMR-based metabolic profiling of urine

INTRODUCTION: Thallium is a heavy metal that is used in the manufacture of electronic components, optical lenses, semiconductor materials, alloys, gamma radiation detection equipment, imitation jewelry, artist's paints, low temperature thermometers, and green fireworks. Cigarette smoking is also a source of thallium. After absorption, it gets accumulated in liver and kidney and causes renal and hepatotoxicity. Thallium demonstrates at least 5 major toxicologic effects viz: Disruption of potassium-dependent processes, Riboflavin sequestration, Interference with cysteine residues, Ribosomal inhibition and Myelin sheath injury. Biomarkers for effects of thallium intoxication are alopecia, neurological effects, and albuminuria which are indicative of exposure to many other toxicants as well. Therefore, methods are needed for more specific biomarkers for effects of thallium exposure. NMR Spectroscopy is a rapid, non destructive technique that allows the detection of a wide range of structurally diverse metabolites simultaneously, providing a metabolic ‘snapshot’ at a particular time point. Urine is readily collected and compared with other biofluids, it has relatively low concentrations of proteins and high concentrations of low molecular-weight compounds thus minimizing sample preparation and result in high-quality measurements due to the narrow line widths of the spectral peaks.