Loss of effects of LPKM on the EPEC-induced reduction of intestinal permeability in vitro and in vivo . (A) TER was found significantly decreased in the EPEC group, compared with control (P < 0.05), which was prevented by the simultaneous treatment of LP (P < 0.05). However, treatment with LPKM showed no effects on the EPEC-induced TER decrease (P > 0.05). Anti-MIMP antibody also inhibited the effect of LP on TER decrease (P > 0.05). (B) Similar findings were obtained for dextran permeability. (C) An increased small intestinal permeability was observed in the IL-10-/- mice at age of 4 weeks and onwards, as compared with the wild-type mice (P < 0.05). LP could decrease small intestinal permeability in IL-10-/- mice, and the effects were more evident at the age of 8–14 weeks when the small intestinal permeability returned to the normal level (P < 0.05). However, LPKM showed no decrease of small intestinal permeability in IL-10-/- mice (P > 0.05). (D) IL-10-/- mice had a significantly increased of colonic permeability, compared with control (P < 0.05). Treatment of LP had no significant effects on the intestinal permeability until week 10. At week 10–15, oral daily administration of pure milk containing LP effectively decreased colonic permeability of IL-10-/- mice (P < 0.05). However, LPKM showed no help in decreasing colonic permeability of IL-10-/- mice (P > 0.05). The intestinal epithelial monolayers were divided into five different experimental groups in triplicate. Each group used 10 animals for determination. *vs. EPEC group, P < 0.05; # vs. *, P < 0.05. The data were expressed as the mean ± standard deviation. Statistical analyses were performed using the SPSS 13.0 software (SPSS Inc., Chicago, IL). Data were analyzed by one-way ANOVA when conditions of homogeneity of variance were present.