Figure 1. LTB₄ production is induced in C. difficile infection.

Experimental timeline for C. difficile infection (A). C57BL/6 mice were treated for 5 days with cefoperazone in drinking water followed by 2 days of recovery period in regular drinking water and then orally infected with 10⁴ spores of strain 630 (left panels) or 10² spores of strain VPI 10463 (right panels). The 630-infected mice develop a mild disease with slight weight loss (B), and mild intestinal inflammation and damage (C), while VPI 10463-infected mice develop a more severe disease showing a rapid weight loss (F) and intense, edematous intestinal inflammation and damage (G). Animals infected with either 630 or VPI 10463 strain showed increased intestinal level of LTB₄ (D, H) but not cysLT (E, I) compared to uninfected animals. Leukotrienes were measured in cecal homogenates by ELISA at the indicated time points. Data are presented as representative images of H&E stained cecum sections or as means ±SEM. Size bars in histological images = 200 μm. Asterisks indicate the cecal lumen and arrows indicate submucosal edema. Statistical comparisons were made using one-way ANOVA followed by Bonferroni’s multiple comparison tests. * P < 0.05 (n = 12 for weight loss and n = 4–5 for ELISA).