(A). Protective effect of retinol in IEC-6 cell migration following 12 and 24 hours of C. difficile toxin A (TxA) exposure (0.01μg/mL) with (M+) or without (M-) mitomycin C pretreatment (5μg/ml, 15-20 min prior to the scraping). IEC-6 cell monolayers were scraped and incubated with retinol (0.01-100nM) diluted in a glutamine-free medium, immediately after standard medium replacement. (B) Representative images of IEC-6 cell migration (X100) at 24 hours following TxA exposure (0.01μg/mL) and retinol supplementation (0.01-100nM) from 6-well plates with (M+) or without (M-) mitomycin C pretreatment. The bars represent mean ± SEM for the number of migrating cells per square millimeter of the scraped area. *P<0.05 compared to in cells incubated with TxA at 12 hours, #P<0.05, compared to in cells incubated with TxA at 24 hours, by ANOVA and Bonferroni's test.