FIG 4.

IEC-MyD88^−/− mice display impaired barrier integrity at early infection time points. (A) FITC-dextran-based intestinal permeability assay performed on WT and IEC-MyD88^−/− mice under uninfected as well as infected (D1 and D3 pi) conditions. IEC-MyD88^−/− mice showed significantly increased barrier permeability compared to that of WT mice at D1 pi. Both groups experienced increased barrier permeability due to infection at D1 and D3 pi compared to that under uninfected conditions. Bars represent the average values for at least 7 mice per group from 3 or more independent experiments. *, P < 0.05; **, P < 0.005. (B) Immunostaining for the proliferation marker Ki-67 (red) and DNA (blue) revealed that WT and IEC-MyD88^−/− mice had increased proliferation in cecal tissue beginning at D1 pi. (C) Quantification of percent Ki-67-positive cells per crypt showed there were significantly more proliferating cells in IEC-MyD88^−/− mice at D1 pi than in WT mice.