Oxidized fat induces oxidative stress but has no effect on NF-κB-mediated proinflammatory gene transcription in porcine intestinal epithelial cells

Abstract

The effect of oxidized frying oils on PPARgamma which is a potent inhibitor of inflammatory responses in the intestine is currently unknown. Thus, the present study aimed to explore the effect of oxidized frying oil on PPARgamma DNA-binding and proinflammatory responses in intestinal epithelial cells. 18 male pigs were fed two different diets containing either fresh fat or oxidized fat (n = 9 each). After 28 d, intestinal epithelial cells were isolated and analyzed for PPARgamma DNA-binding, NF-kappaB DNA-binding and NF-kappaB target gene expression. In addition, markers of lipid peroxidation and antioxidant status were determined. Feeding the oxidized fat slightly, but not significantly, activated PPARgamma DNA-binding in intestinal epithelial cells when compared to fresh fat. In addition, oxidized fat increased the concentration of TBARS and reduced the concentrations of alpha-tocopherol and activities of antioxidant enzymes relative to fresh fat (P < 0.05). No effect of the oxidized fat was observed on NF-kappaB DNA-binding and NF-kappaB target gene expression in intestinal epithelial cells. The present study suggests that moderate PPARgamma activation and induction of oxidative stress by oxidized frying oil have no implication for NF-kappaB-mediated proinflammatory gene expression in porcine intestinal epithelial cells.