Proteomic analysis and identification of intestinal FBP as a predictor of gut dysfunction during heatstroke in mice

Gut-derived endotoxin and pathogenic bacteria have been proposed to be an important causative factor of morbidity and death during heatstroke. However, the molecular changes underlying heat stress-induced small intestine lesions have not yet been well characterized.

A heatstroke model was established in mice, and the thermal response and pathologic changes in the small intestine were examined during heat stress. Proteins extracted from the small intestine of the heated and control mice were separated by two-dimensional (2D) gel electrophoresis, and different protein spots were further identified by peptide mass fingerprint. Targeted proteins were further verified by Western blot and immunohistochemistry analysis.

Pathologic changes in the small intestine during heat stress were found to be substantial. Using 2 D gel proteomics we identified 14 proteins that were regulated differentially in the small intestine of the mice subjected to heat stress. These 14 identified proteins, seven were down-regulated and the other seven were up-regulated, appeared to be involved in metabolism, chaperone, cell skeleton, defense, signal transduction, DNA repair, and recombination. Using Western blot and immunohistochemical analysis, we further confirmed that down-regulated expression of intestinal fructose 1,6-bisphosphatase (FBP) correlated to the severity of small intestine lesions during heat stress and cooling treatment.

Our results identified 14 differentially expressed proteins, which may contribute to the understanding of molecular mechanisms underlying intestinal injury during heatstroke. Furthermore, intestinal FBP, one of the seven down-regulated proteins, may function as a potential marker for prognosis of gut dysfunction.