Figure 5.

Different responses elicited by infection closely related mycobacterial species after secondary exposure. (A) Experimental scheme. (B–D) Upon necropsy at 1 day after secondary exposure, colon length, liver and spleen weight were measured. (B) Total liver weight in Gram. (C) Total spleen weight in Gram. (D) Colon length of MAP, MAA and MHS infected group at 1 day after secondary exposure with the same mycobacteria species (n = 3–5). (E) Histology score of the colon analyzed at 1 day after secondary exposure (n = 3–5). n.d = not detected, histology score = 0. (F) H&E staining of colon tissue sections at day 1 after secondary exposure. Scale bars, 25 μm. H₂O+PBS+PBS (upper left) showed normal tissue. DSS+PBS+PBS (upper right) showed mild invasion of inflammatory cells (black arrow), mild epithelial hyperplasia and desquamation of epithelial cells (purple arrow). DSS+MAA+MAA (middle left) showed mild invasion of inflammatory cells (black arrow), moderate epithelial hyperplasia. DSS+MHS+MHS (middle right) showed mild invasion of inflammatory cells (black arrow), mild edema (green arrow), moderate epithelial hyperplasia. DSS+MAP+MAP (bottom part) showed severe transmural invasion of inflammatory cells (black arrow), ulceration (red arrow), moderate edema (green arrow) and severe epithelial hyperplasia. Graph show a representative of at least two independent experiments, show as Mean ± SEM. ^*P < 0.05; ^**p < 0.01; ^***p < 0.001, one-way ANOVA with Tukey's multiple comparison post-test.