Caspase-3, 3-Nitrotyrosine (3-NT) staining scores and nitrite measurements at 14 day post-infection.

(A) Semi-quantification of immunohistochemical Caspase-3 staining in distal colon from C. rodentium infected mice with and without VIP treatment (B) Semi-quantification of immunohistochemical 3-NT in distal colon from infected mice with and without VIP treatment. (C) Nitrite concentration in the murine distal colon of infected and VIP treated mice (n = 2–7 mice/group). Of the mice harvested day 14 post infection, one mouse died in the group that was administered VIP day 5–10 and two in the group that were administered VIP day 10–14. Data about dead animals is not included in the graphs, and the group with only two mice remaining (VIP day 10–14) was omitted from the statistical analysis. (D) Nitrite concentration in the in vitro mucosal intestinal model infected with C. rodentium and treated with cytokines in the presence and absence of VIP. (E-I) Representative photos showing caspase-3 tissue localization in distal colon from C. rodentium infected mice with and without VIP treatment. Note that although many cells in the tissue from infected mice stains pale brown, a study that performed both Caspase-3 and Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL) assays in parallel to detect DNA degradation, demonstrated that the proportion of cells that are in late stage apoptosis correspond to the strongly stained cells, not the light brown cells [58]. (J-N) Representative photos showing 3-NT tissue localization in distal colon from C. rodentium infected mice with and without VIP treatment. Scale bar 200 μm, magnification x400. Statistics: data are presented as mean ± S.E.M. and analysed by ANOVA with Student Newman-Keuls Multiple Comparison post hoc test: * PPP<0.001.