Caco-2 cells were incubated with iron/ascorbate for 1-24 h, they exhibited increased malondialdehyde levels and decreased polyunsaturated fatty acid proportion in favor of saturated fatty acids. These modifications were accompanied with alterations in membrane fluidity and permeability. The oxidative stress did not induce changes in the antioxidant enzyme activity of superoxide dismutase, catalase, glutathione peroxidase, and glutathione transferase, or in cellular glutathione content. However, iron/ascorbate-mediated lipid peroxidation promoted inhibitor-B degradation and NF-B activation, as well as gave rise to IL-8, cyclooxygenase-2, and ICAM-1. These results support the importance of oxidant/ antioxidant balance in the epithelial cell inflammatory response. oxidative stress; membrane transport; nuclear factor-B; cyclooxygenase-2; intercellular adhesion molecule-1.

Bacterial endotoxin and prooxidants may overwhelm antioxidant defenses and become deleterious to enterocyte function, whereas butyric acid and BHT may provide antioxidant protection.

No abstract