Effects of anti-allergic drugs on intestinal mastocytosis and worm expulsion of rats infected with Neodiplostomum seoulense

Abstract

The effects of anti-allergic drugs on intestinal mastocytosis and the expulsion of Neodiplostomumseoulense were observed in Sprague-Dawley rats, after oral infection with 500 metacercariae. The drugs used werehydroxyzine (a histamine receptor H1 blocker), cimetidine (a H2 blocker), cyclosporin-A (a helper T-cell suppressant),and prednisolone (a T- and B-cell suppressant). Infected, but untreated controls, and uninfected controls, wereprepared. Worm recovery rate and intestinal mastocytosis were measured on weeks 1, 2, 3, 5, and 7 post-infection.Compared with the infected controls, worm expulsion was significantly (P < 0.05) delayed in hydroxyzine- andcimetidine-treated rats, despite mastocytosis being equally marked in the duodenum of all three groups. In thecyclosporin-A- and prednisolone-treated groups, mastocytosis was suppressed, but worm expulsion was only slightlydelayed, without statistical significance. Our results suggest that binding of histamine to its receptors on intestinalsmooth muscles is more important in terms of the expulsion of N. seoulense from rats than the levels of histaminealone, or mastocytosis.