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Investigations into the biochemical effects of region-specific nephrotoxins
K P Gartland1, F W Bonner, J K Nicholson
1Department of Chemistry, Birkbeck College, University of London, United Kingdom.
Abstract:
1H NMR spectroscopy provides a useful initial biochemical screen with which to detect abnormal patterns of metabolites in urine collected from animals with different sites of nephrotoxic lesions. Male Fischer 344 rats were treated with nephrotoxic doses of sodium chromate (pars convoluta of proximal tubule), cisplatin, hexachlorobutadiene, mercury II chloride (pars recta of proximal tubule), propylene imine, and bromoethanamine (renal papilla) in order to induce damage in specific regions of the kidney. Urine was collected for up to 48 hr after dosing and was analyzed by 1H NMR spectroscopy (400 MHz) and conventional biochemical methods to provide biochemical fingerprints of urine in various site-specific nephrotoxic states. Hexachlorobutadiene and HgCl2 produced severe glycosuria and transient enzymuria. 1H NMR urinalysis revealed aminoaciduria, glycosuria, and lactic aciduria after exposure to all proximal tubular toxins except cisplatin, whereas papillary insult resulted in early elevations in urinary trimethylamine N-oxide and dimethylamine, together with later elevations in urinary acetate, succinate, and N,N-dimethylglycine (after propylene imine). Trimethylamine N-oxide and dimethylamine are suggested as novel markers of site-specific renal papillary injury in the rat.
Insights
Proton NMR spectroscopy detects specific urinary metabolite changes indicating kidney damage location. Trimethylamine N-oxide and dimethylamine show promise as novel markers for renal papillary injury.
Area of Science:
- Biochemistry
- Toxicology
- Analytical Chemistry
Background:
- Kidney damage can be site-specific, affecting different parts of the nephron.
- Detecting the location of kidney injury is crucial for understanding toxicity and prognosis.
- Conventional biochemical methods may not always pinpoint the exact site of nephrotoxic lesions.
Purpose of the Study:
- To evaluate 1H NMR spectroscopy as a tool for identifying site-specific nephrotoxic lesions in rats.
- To establish biochemical fingerprints of urine following exposure to known nephrotoxins targeting specific kidney regions.
- To identify novel urinary biomarkers for renal papillary injury.
Main Methods:
- Male Fischer 344 rats were administered specific nephrotoxins targeting the proximal tubule (sodium chromate, hexachlorobutadiene, mercury II chloride) or renal papilla (propylene imine, bromoethanamine).
- Urine samples were collected up to 48 hours post-dosing.
- Urine was analyzed using 1H NMR spectroscopy (400 MHz) and conventional biochemical assays.
Main Results:
- 1H NMR urinalysis revealed distinct metabolite patterns correlating with the site of kidney injury.
- Proximal tubular toxins (except cisplatin) induced aminoaciduria, glycosuria, and lactic aciduria.
- Hexachlorobutadiene and mercury II chloride caused severe glycosuria and transient enzymuria.
- Renal papillary insult led to early increases in urinary trimethylamine N-oxide and dimethylamine, followed by acetate, succinate, and N,N-dimethylglycine.
Conclusions:
- 1H NMR spectroscopy is a valuable tool for detecting site-specific nephrotoxic lesions.
- Urinary trimethylamine N-oxide and dimethylamine are proposed as novel biomarkers for rat renal papillary injury.
- Metabolite profiling of urine via 1H NMR can provide insights into the location and extent of kidney damage.