Role of peroxisome proliferator-activated receptor-α in ileum tight junction alteration in mouse model of restraint stress

Restraint stress induces permeability changes in the small intestine, but little is known about the role of endogenous peroxisome proliferator-activated receptor-alpha (PPAR-alpha) ligand in the defects of the tight junction function. In the present study, we used PPAR-alpha knockout mice to understand the roles of endogenous PPAR-alpha on ileum altered permeability function in models of immobilization stress. The absence of a functional PPAR-alpha gene in PPAR-alpha knockout mice resulted in a significant augmentation of the degree of 1) TNF-alpha production in ileum tissues; 2) the alteration of zonula occludens-1, occludin, and beta-catenin (immunohistochemistry); and 3) apoptosis (terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling staining, Bax, Bcl-2 expression). Taken together, our results demonstrate that endogenous PPAR-alpha ligands reduce the degree of tight junction permeability in the ileum tissues associated with immobilization stress, suggesting a possible role of endogenous PPAR-alpha ligands on ileum barrier dysfunction.