Modulation of Rat Intestinal Nuclear Factor NF-κB by Gum Arabic

The objective of this study was to test the hypothesis that in an animal model of cathartic-induce intestinal dysfunction the proabsorptive effects of gum arabic (GA) could be associated with modulation of nuclear factor-κB (NF-κB) and with reduction of the inflammatory response caused by cathartics, as evidenced by intestinal mucosa cytokine production and gene expression. Juvenile male rats were given a phenolphthalein–magnesium citrate solution for 6 days, by itself or supplemented with either 10 or 20 g L−1 GA, as a sole source of fluid. The controls given were tap water alone or with added 20 g L−1 GA. The animals were euthanized and small-intestinal mucosa nuclear fractions and RNA were isolated. NF-κB p65 activity was highest after administration of cathartics, lowest in controls, and intermediate in GA-treated rats. Mucosal IL-1β was overexpressed in tissues from cathartic-treated rats and from rats given high-GA solutions. Gene-array analysis revealed a complex pattern of gene regulation by cathartics which selectively upregulated several subfamilies of cytochrome P-450 family 2 genes. Co-administration of GA did not block this effect. These findings suggest that local anti-inflammatory effects on the small intestine could be obtained by administration of a nonabsorbable proteoglycan such as GA.