Dynamic proteomic and metabonomic analysis reveal dysfunction and subclinical injury in rat liver during restraint stress

Stress is a risk factor for many diseases. In this study, we used fluorescence difference gel electrophoresis combined MALDI-TOF/TOF and 1H-NMR to monitor the intracellular processes in rat liver at proteomic and metabonomic levels when a rat was treated with restraint stress for 8 weeks. Dynamic changes in 42 proteins and 32 chemical groups were monitored and identified. These proteins and chemical groups were implicated in glycolysis, the tricarboxylic acid cycle, fatty acid oxidation, and the urea cycle. To verify the DIGE result, three proteins including DJ-1, Blvrb and AdoHycase were validated by Western blot. Furthermore, some metabolites related to diseases such as lactate, fatty acid, glucose and homocysteine, were observed to be increasing during 8 weeks of restraint stress. Our data indicated that subclinical hepatic injury occurs during restraint stress, including inhibition of glycolysis and gluconeogenesis in the liver, and dysfunction of fatty acid beta-oxidation. The results suggest a comprehensive map that addresses how functional proteins act on metabolites to produce energy and process materials in rat liver as it responds to restraint stress. Further functional study on these dynamic change proteins and metabolites may lead to better understanding of the mechanisms of stress-induced diseases.