Increased susceptibility to Trichuris muris infection and exacerbation of colitis in Mdr1a-/- mice.

AIM: To investigate the influence of Trichuris muris (T. muris) infection in a mouse model of genetic susceptibility to inflammatory bowel disease, Mdr1a-/-.

METHODS

Mdr1a-/- mice were housed under specific pathogen free conditions to slow the development of colitis and compared to congenic FVB controls. Mice were infected with approximately 200 embryonated ova from T. muris and assessed for worm burden and histological and functional markers of gut inflammation on day 19 post infection.

RESULTS

Mdr1a-/- mice exhibited a marked increase in susceptibility to T. muris infection with a 10-fold increase in colonic worm count by day 19 pi compared to FVB controls. Prior to infection, Mdr1a-/- exhibited low-level mucosal inflammation with evidence of an enhanced Th1 environment. T. muris infection accelerated the progression of colitis in Mdr1a-/- as evidenced by marked increases in several indicators including histological damage score, mucosal CD⁺ T-cell and DC infiltration and dramatically increased production of pro-inflammatory cytokines.

CONCLUSION

These data provide further evidence of the complex interaction between T. muris and an inflammatory bowel disease (IBD)-susceptible host which may have relevance to the application of helminth therapy in the treatment of human IBD.