Intestinal epithelial barrier protective effect of nut oils (walnut, almond, pistachio, and pine nut) on TNF-α/IFN-γ induced damage in Caco-2 cell monolayers

Damage to the intestinal barrier causes intestinal inflammation, which could lead to the development of gastrointestinal diseases. Nut oils contain an abundance of unsaturated fatty acids, which are responsible for most of the bioactivities of nut oils. Here, the protective effect of four nut oils on the intestinal epithelial barrier was confirmed using Caco-2 cells damaged by tumor necrosis factor-alpha/interferon-gamma treatment. Nut oils effectively increased transepithelial electronic resistance and lowered paracellular fluorescein isothiocyanate-dextran permeability in damaged Caco-2 cells. Furthermore, the nut oils inhibited the pro-inflammatory cytokine production of interleukin-6, which was induced by the inflammatory response. In particular, walnut oil effectively improved tight junction protein (occludin and zonula occludens-1) expression and distribution in damaged Caco2 cells. In conclusion, our findings suggest that nut oils are promising candidates for impaired intestinal barrier protection.