Studies of the biochemical toxicology of uranyl nitrate in the rat

Abstract

High resolution 1H NMR spectroscopy of urine and plasma, conventional clinical chemical methods and histopathology have been applied to investigate the effects of uranyl nitrate (UN) on renal function and biochemistry in the Fischer 344 (F344) rat. Administration of UN (5-20 mg/kg) to male F344 rats resulted in a dose-related proximal nephropathy assessed conventionally by histopathology and urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG), and related to changes in the patterns of low MW metabolites observed in 400 MHz 1H NMR spectra of urine. The changes in urinary metabolite profiles included elevations in glucose accompanied by minor elevations in certain amino acids (alanine, valine and glutamate). 1H NMR urinalysis also revealed altered excretion of low MW metabolites which are not routinely measured, such as L-lactate, acetate, citrate, succinate and 2-oxoglutarate (2-OG). In addition, the striking appearance of high concentrations of 3-D-hydroxybutyrate (HB) in the urine was noted, in the absence of acetoacetate or acetone, and it is suggested that this may provide a new marker of proximal tubular damage for certain types of nephrotoxic mechanism. Broadening of the 1H NMR signals of citrate following 10 mg/kg UN was shown to be due to a dynamic exchange process involving chelation with urinary Ca2+ and Mg2+ ions. Conventional biochemical analysis of plasma from UN-treated rats revealed dose-related increases in creatinine, urea and HB concentrations. 1H NMR-detected evidence of raised alanine amino-transferase (ALT) levels in rats administered the highest dose of UN was indicated by the partial deuteration of alanine in lyophilised plasma reconstituted in 2H2O. The degree of 1H NMR-detected abnormalities agreed well with histopathological observations and conventional biochemical indices of nephrotoxicity and more fully characterised the renal changes produced by UN. The significance of HB-uria in UN-induced proximal nephropathy is discussed in relation to biochemical observations on other proximal nephrotoxins.

Use of liquid chromatography/time‐of‐flight mass spectrometry and multivariate statistical analysis shows promise for the detection of drug metabolites in biological fluids

“…The use of multivariate analysis of spectroscopic data has been pioneered by Nicholson and Lindon et al [9][10][11] for metabonomics analysis of biological fluids. In this approach, mathematical algorithms identify peaks/analytes that are responsible for group clustering, and have allowed many new and novel markers of drug toxicity to be identified.…”

Comparison of the specificity and sensitivity of traditional methods for assessment of nephrotoxicity in the rat with metabonomic and proteomic methodologies

“…Two papers (Bandara et al, 2003a,b) reported different subsets of results from the same experiment and were therefore treated as one paper for the purposes of this review. The objective of the study by Anthony et al (1994a), summarised in Table 1, was to provide a characterisation of the structural and functional consequences of uranyl nitrate nephrotoxicity using 1 H-NMR spectroscopy (without any subsequent bioinformatic data manipulation), blood and urine chemistry and histopathology. The NMR markers that did show changes generally correlated well with the changes detected by conventional clinical chemistry.…”

Amoxicillin Is Effective against Penicillin-Resistant Streptococcus pneumoniae Strains in a Mouse Pneumonia Model Simulating Human Pharmacokinetics

“…Sustained leukopenia was induced by three intraperitoneal injections (150 mg/kg of body weight) of cyclophosphamide (Endoxan; Sarget Laboratories, Mérignac, France) per day starting 4 days before the bacterial challenge. Circulating leukocyte counts dropped from about 7,000/mm 3 initially to about 1,200/mm 3 on the day of infection, with neutrophil counts at about 100/mm 3 . The average leukocyte count reached 1,000/mm 3 of blood 1 day after infection and then increased progressively to 4,700/mm 3 of blood 3 days after infection (neutrophil count around 500/mm 3 ) to return to a normal count around 7,100/mm 3 of blood 5 days after infection (10,11).…”

“…Circulating leukocyte counts dropped from about 7,000/mm 3 initially to about 1,200/mm 3 on the day of infection, with neutrophil counts at about 100/mm 3 . The average leukocyte count reached 1,000/mm 3 of blood 1 day after infection and then increased progressively to 4,700/mm 3 of blood 3 days after infection (neutrophil count around 500/mm 3 ) to return to a normal count around 7,100/mm 3 of blood 5 days after infection (10,11). The organisms were introduced by intratracheal instillation as described in detail elsewhere (9).…”

“…We chose this protocol because it induces less early mortality than the protocol described by Craig (10 mg/kg 3 days before infection) (1). Uranyl nitrate induces reversible acute tubular necrosis and has long been used to induce experimental renal failure (3,37). We dissolved the uranyl nitrate crystals, and we diluted the solution to the desired concentration.…”