[Study of Plasma amino acid related metabolites of septic rats using gas chromatography-mass spectrometry].

OBJECTIVE: To reveal the pathophysiological changes of sepsis, the plasma metabonomics of septic rats was determined and differential metabolites were determined by gas chromatography-mass spectrometry (GC-MS).

METHODS: Male Spraguee-Dawley (SD) rats about 8 weeks were randomly divided into sham group (n = 18) and sepsis group (n = 24). Cecal ligation and puncture (CLP) was used to build sepsis model, while cecum was kept intact only in the sham group. 6 hours after the operation, rats were anesthetized, and blood was harvested through heart thoracotomy. Then the plasma metabonomics was detected by GC-MS and metabolic profile analysis was performed to find the relative differential metabolites.

RESULTS: Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) showed that the metabolic profiling of the sepsis group was significantly different from the sham group. 259 kinds of metabolites were got by GC-MS, and 69 kinds of differential metabolites were found between sham group and sepsis group, in which 23 differential metabolites were related to amino acid metabolism. Compared with sham group, the contents of putrescine, N-glutamic acid, hydroxynorvaline, 3-cyanuric acid, D-alanyl-D-alanine and urea in the plasma of septic rats increased significantly, which ratios of sepsis/sham group were 10.876, 6.394, 2.800, 2.226, 1.323, 1.203, respectively (all P < 0.05). On the other hand, the contents of oxygen generation of proline, citrulline, glutamine, su-beta-hydroxy aspartic acid, citric acid, N-methyl-DL-alanine, serine, lysine, threonine, N-formyl-L-methionine, methionine, alanine, nicotinuric acid, N-methyl-L-glutamic acid, trans-4-hydroxy-L-proline, proline, L-glutamic acid in the plasma of septic rats decreased significantly, which ratios of sepsis/sham group were 0.858, 0.853, 0.834, 0.816, 0.816, 0.814, 0.813, 0.801, 0.793, 0.792, 0.774, 0.766, 0.748, 0.727, 0.716, 0.674, 0.603, respectively (all P < 0.05).

CONCLUSIONS: Through the GC-MS analysis of plasma metabonomics of septic rats, we found abnormal energy metabolism changes. The content of amino acid in plasma might be a method to evaluate the energy metabolism status of sepsis.