Evaluation of Bioeffects of a Long‐term Administering Change on Rat by Proton NMR Method and Biochemical Examination

AbstractHigh resolution1H nuclear magnetic resonance (NMR) spectroscopy has been employed to assess long‐term toxicological effects of ChangLe (a kind of rare earth complex applied in agriculture). Male Wistar rats were administrated orally with ChangLe at doses of 0, 0.1, 0.2, 2.0, 10 and 20 mg/kg body weight daily, respectively, for 6 months. Urine was collected at day 30, 60, 90 and serum samples were taken after 6 months. Many low‐molecular weight metabolites were identified by1H NMR spectra of rat urine. A decrease in citrate and an increase in ketone bodies, creatinine, DMA, DMG, TMAO, and taurine in the urine of the rats receiving high doses were found by1H NMR spectra. These may mean that high‐dosage of ChangLe impairs the specific region of liver and kidney, such as renal tubule and mitochondria. The decrease in citrate and the increase in succinate and α‐ketoglutarate were attributed to a combination of the inhibition of certain citric acid enzymes, renal tubular acidosis and the abnormal fatty acid catabolism. The information of the renal capillary necrosis could be derived from the increase in DMA, DMG and TMAO. The increase in taurine was due to hepatic mitochondria dysfunction. The conclusions were supported by the results of biochemical measurements and enzymatic assay. No obviously toxicological effects on metabolism were found for low‐dosage ChangLe, but further studies on safety of ChangLe applied to agriculture are still required.