Integrated metabolomic analysis of the nano-sized copper particle-induced hepatotoxicity and nephrotoxicity in rats: a rapid in vivo screening method for nanotoxicity

Despite an increasing application of copper nanoparticles, there is a serious lack of information concerning their impact on human health and the environment. In this study, the biochemical compositions of urine, serum, and extracts of liver and kidney tissues of rats treated with nano-copper at the different doses (50, 100, and 200 mg/kg/d for 5 d) were investigated using ¹H NMR techniques with the pattern recognition methods. Serum biochemical analysis and histopathological examinations of the liver and kidney of all the rats were simultaneously performed. All the results indicated that the effects produced by nano-copper at a dose of 100 or 50 mg/kg/d were less than those induced at a higher dose of 200 mg/kg/d. Nano-copper induced overt hepatotoxicity and nephrotoxicity at 200 mg/kg/d for 5 d, which mainly involved scattered dot hepatocytic necrosis and widespread renal proximal tubule necrosis. Increased citrate, succinate, trimethylamine-N-oxide, glucose, and amino acids, accompanied by decreased creatinine levels were observed in the urine; furthermore, elevated levels of lactate, 3-hydroxybutyrate, acetate, creatine, triglycerides, and phosphatide and reduced glucose levels were observed in the serum. The predominant changes identified in the liver tissue aqueous extracts included increased lactate and creatine levels together with reduced glutamine and taurine levels, and the metabolic profile of the kidney tissue aqueous extracts showed an increase in lactate and a drop in glucose. In the chloroform/methanol extracts of the liver and kidney tissues, elevated triglyceride species were identified. These changes suggested that mitochondrial failure, enhanced ketogenesis, fatty acid β-oxidation, and glycolysis contributed to the hepatotoxicity and nephrotoxicity induced by nano-copper at 200 mg/kg/d for 5 d. An increase in triglycerides in the serum, liver and kidney tissues could serve as a potential sensitive biomarker reflecting the lipidosis induced by nano-copper. The data generated from the current study completely supports the fact that an integrated metabolomic approach is promising for the development of a rapid invivo screening method for nanotoxicity.