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

Objective and design: The effect of oxidized frying oils on PPAR gamma 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 PPAR gamma DNA-binding and proinflammatory responses in intestinal epithelial cells. Material and methods: 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 PPAR gamma DNA-binding, NF-kappa B DNA-binding and NF-kappa B target gene expression. In addition, markers of lipid peroxidation and antioxidant status were determined. Results: Feeding the oxidized fat slightly, but not significantly, activated PPAR gamma 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 cc-tocopherol and activities of antioxidant enzymes relative to fresh fat (P < 0.05). No effect of the oxidized fat was observed on NF-kappa B DNA-binding and NF-kappa B target gene expression in intestinal epithelial cells. Conclusions: The present study suggests that moderate PPAR gamma activation and induction of oxidative stress by oxidized frying oil have no implication for NF-kappa B-mediated proinflammatory gene expression in porcine intestinal epithelial cells.