Analysis of urinary metabolic profile in aging rats undergoing caloric restriction

Background and aims: While caloric restriction (CR) is associated with a prolonged lifespan in multiple species by regulating metabolism, a comprehensive profile of metabolism under CR conditions remains largely unclear. Therefore, in this study we aimed to characterize the metabolomic profiling associated with CR using a rat model. Methods: Rapid resolution liquid chromatography/electrospray ionization quadrupole-time of flight mass spectrometry (RRLC/ESI-Q-TOFMS) was employed to analyze metabolomic profiling of urine samples from aging rats who underwent caloric restriction (CR; n=7) or were provided a normal diet (N; n=8) for 12 weeks time. Multivariate data analysis was performed on the mass data of metabolomic profiles to uncover the differences between the CR and N groups. Results: CR treatment led to manifest metabolic changes in aging rats, and fifteen urinary metabolites including hypoxanthine, hippurate, dimethylglycine and creatinine were significantly different in the rat groups. Conclusion: Our study demonstrates the high reliability of the HPLC-based metabolomic approach towards the study of anti-aging effects induced by CR, while the urinary metabolites we identified may become potential biomarkers of aging.