Fig. 2

Microscopic large intestinal changes in C. jejuni infected secondary abiotic Nod2^−/− mice. Secondary abiotic wildtype (WT; white circles) and Nod2^−/− mice (black circles) were generated by broad-spectrum antibiotic treatment and perorally infected with C. jejuni strain 81-176 by gavage at day (d) 0 and d1. a Histopathological mucosal changes were assessed in H&E stained large intestinal paraffin sections. Furthermore, the average number of colonic epithelial b apoptotic cells (positive for caspase-3, Casp3) and c proliferating cells (positive for Ki67) from six high power fields (HPF, ×400 magnification) per animal was determined microscopically in immunohistochemically stained colonic paraffin sections at day 7 following C. jejuni infection. Naive (N) secondary abiotic mice served as uninfected controls. Medians (black bars), levels of significance (p-values) determined by Mann–Whitney U test and numbers of analyzed animals (in parentheses) are indicated. Data were pooled from four independent experiments