¹H NMR-based urinary metabolic analysis of high-dose cyclophosphamide-induced toxicity in mice

Cyclophosphamide (CP) is widely used in clinical fields. Beside its therapeutic effects, CP shows toxicity depending on dose and administration schedule. In this study, the urinary metabolic profiles were investigated in mice intraperitoneally injected with high-dose CP (150 mg/kg body weight) once a week over four weeks using nuclear magnetic resonance (NMR)-based metabolomics. Twenty-six metabolites were identified as potential biomarkers by multivariate statistical analysis. A decrease in isoleucine, alanine, N-acetylglutamic acid, proline, methionine, valine, phenylacetylglulamine, dimethylamine, hippurate, acetic acid, lactate, α-oxoglutarate, citrate, malonic acid, creatinine, niacin, β-hydroxybutyrate, and betaine, whereas an increase in leucine, glutamate, glycine, taurine, phenylacetylglycine, glucose, creatine, and choline were observed in the urine of high-dose CP-treated mice. Metabolites related to amino acid metabolism, energy metabolism, and gut microbial metabolism were changed markedly in the urine. Further metabolic pathway analysis suggested that seven metabolic pathways, including alanine, aspartate, and glutamate metabolism, arginine biosynthesis, glyoxylate, and dicarboxylate metabolism, glycine, serine and threonine metabolism, d-glutamine and d-glutamate metabolism, arginine, and proline metabolism, citrate cycle, as well as the gut microbiota metabolism, were significantly involved in response to high-dose CP treatment. These findings help to predict the toxicity of CP and understand the biological mechanism of the toxicity of CP.