Dextran sodium sulfate alters cytokine production in macrophages in vitro

Macrophages have been assumed to have a crucial role in the development of inflammatory bowel disease (IBD). However, involvement of intestinal macrophages in IBD onset and functional alterations of macrophages during IBD development has not been clarified. We investigated the effect of exposure of compounds used in the induction of colitis in mice on the immune responses of peritoneal macrophages in mice. 2,4,6- trinitrobenzenesulfonic acid and oxazolone did not affect the production of interleukin (IL)-10 and IL-12 from lipopolysaccharide (LPS)-stimulated peritoneal macrophages from BALB/c mice. A significant increase in IL-10 secretion and decrease in IL-12 production from LPS-stimulated macrophages were observed upon exposure to dextran sodium sulfate (DSS). TNF-α production was enhanced significantly by exposure to DSS and LPS. The level of nitric-oxide production from macrophages was increased slightly by exposure to DSS and LPS. Expression of sphingosine kinase-1 and LIGHT (both of which are specific biomarkers of M2b macrophages) was observed in macrophages upon DSS exposure. Alteration of cytokine production in macrophages was observed upon DSS exposure in the absence of LPS stimulation. Peritoneal macrophages from C57BL/6 mice showed similar responses to peritoneal macrophages from BALB/c mice against DSS. These results suggest that DSS directs the immune response of macrophages towards the M2b phenotype.