NMR metabolic profiling combined with two-step principal component analysis for toxin-induced diabetes model rat...

Nuclear magnetic resonance-based metabolic profiling (NMR-MP) was applied to evaluate disorder model animals using urine. Diabetic nephropathy was established in this experiment by administering streptozotocin to Wistar rats, which immediately developed diabetes after toxin-treatment and then gradually produced albumin-containing urine (albuminuria). Urine samples were collected for the first 4 weeks after toxin treatment. Predominant urinary sugar signals were seen in (1)H-NMR spectra of diabetes rat urine, and spectra were processed and subjected to multivariate analysis. Principal component analysis (PCA) identified 3 outliers among 20 individuals. Outlier rats did not develop urinary sugar and were later found to be rats insufficient to establish diabetes models. A second PCA was performed excluding the additional glucose-signal region (3.2-6.3 ppm), as glucose signals had a predominant effect that may mask details of other metabolic profiles. Consequently another outlier was revealed. This exceptional rat did not develop albuminuria even after producing glucosuria for 14 weeks. NMR metabolic profiling provides good guidance to evaluate biophysical conditions of animals, enabling detection of abnormalities in the early stage of toxicological experiments.