Abstract
BACKGROUND AND PURPOSE: The inflammatory bowel diseases(IBD) such as ulcerative colitis(UC) are intractable diseases of unknown origin. The mucosal injury of UC is presumed to be partly caused by reactive oxygen species(ROS) produced by neutrophils. Chronic inflammation of UC results in chronic anemia, to which iron is given. In this study, to evaluate the effect of sodium ferrous citrate(SFC) on neutrophil functions, we measured superoxide generation and migration of neutrophils treated with SFC in vitro.
METHODS: Superoxide generation induced by phorbol myristate acetate(PMA), opsonized zymosan(OPZ) and N-formyl-menthionyl-leucyl-phenylalanine(fMLP) was determined based on the superoxide dismutaseinhibitable cytochrome c reduction. To further clarify the inhibitory mechanism of SFC, the membrane fraction was isolated and NADPH-dependent superoxide production was measured. Moreover, neutrophil migration was evaluated with a Boyden chamber assay using zymosan-activated serum (C5a) as a chemoattractant.
RESULTS: SFC dose-dependently inhibited the superoxide production induced by all the stimuli examined. Similarly, SFC-treatment inhibited the activity of NADPH oxidase in the membrane fraction of neutrophils. In addition, SFC suppressed chemotaxis toward zymosan-activated serum in a dose-dependent fashion.
CONCLUSIONS: In this study, we revealed that SFC could suppress neutrophil functions such as superoxide generation (NADPH oxidase activity) and migration. During episodes of IBD, stimulated neutrophils are accumulated in inflamed mucosa via the migration through vascular endothelium, where they release ROS such as superoxide. Thus, the present observations suggest that SFC may have a potential to reduce mucosal injury by suppressing migration and ROS generation by neutrophils in UC.
