Untargeted metabolite profiling of porcine urine samples: individual's response to stress during hemorrhage, shock and recovery.

摘要

Urine output was highly variable. Individual animals had difference in volume of up to 160-fold between time points and 35-fold between animals at a single time point. Urine samples exhibited a dramatic spread of standard deviation. Over two thirds of molecular features (baseline) expressed coefficient of variation between 50 and 100%, in contrast to both 2h samples showing 36% and 26% for control and stress, respectively. Instrument response was linear with respect to sample concentration as tested by dilution (R~2=0.9985, for global and R~2=0.8554-0.9999, for vastly represented molecular features). Signal correction to median fold change and log transformation followed by PCA and HCA were successfully used to recognize difference between control and shock animals and pinpointed the most contributing molecular features. Clear differentiation of control and shock groups 2hrs after injury was demonstrated. The significant reduction in sample variability in stressed animals suggests that trauma has initiated metabolic response mechanisms that's mask biological diversity. UPLC-MS analysis of urine is a promising approach for tracking strong changes in animal physiology, despite the dramatic differences in concentration that often confound the use of this easily obtainable biological fluid.