ANTIINFLAMMATORY EFFECTS OF HUMAN-MILK ON CHEMICALLY-INDUCED COLITIS IN RATS

We examined the effects of a human milk diet on rats with chemical col itis induced with a 4% acetic acid enema. Colonic myeloperoxidase acti vity was used as a surrogate marker for neutrophil infiltration. Contr ol rats fed rat chow had little colonic myeloperoxidase activity; geom etric mean, 0.27 U/g of tissue. Rats with colitis fed rat chow had sig nificantly increased colonic myeloperoxidase activity (geometric mean, 6.76 U/g, p < 0.01 versus no colitis), as did rats with colitis fed i nfant formula or Pedialyte (geometric mean, 6.92 and 8.13 U/g, respect ively, both p < 0.01 versus no colitis). Animals with colitis fed huma n milk had significantly lower colonic myeloperoxidase activity (geome tric mean, 2.34 U/g) than did animals with colitis fed either chow or infant formula (p < 0.001). Similar effects were seen in rats with col itis fed infant formula supplemented with recombinant human IL-1 recep tor antagonist (geometric mean, 1.95 U/g). These data show that orally administered human milk has an antiinflammatory effect on chemically induced colitis in rats, which may be mediated in part by IL-1 recepto r antagonist contained in human milk.