Milk- and soy-based diets have differential effects on colitis and colon gene expression in the Il10-/- mouse

Milk and soy are reported to contain bioactive molecules with antibacterial and immunomodulatory actions, which may be beneficial to people with IBD. The aim of this study was to determine whether diets containing ruminant milk or soy solids reduce intestinal inflammation in Il10-/- mice. Male Il10-/- mice and C57BL/6J mice were fed diets containing 40% (w/w) sheep, goat, or cow whole milk powder, 40% (w/w) soy solids (NOW® Foods Soy Milk Powder, Instant), or one of two control diets (casein-free modified-AIN76A or standard AIN76A) from 4 to 11 weeks of age. Diets were based on AIN76A, which was included as an inter-experimental control for inflammation. For all diets except AIN76A, total protein, fat, carbohydrate and energy were kept as similar as possible. Weight and food intake were measured throughout the experiment (three times weekly), and intestinal tissue was taken for histopathology evaluation of inflammation and analysis of gene expression. Analysis of mouse weight and feed intake both showed a significant strain-diet interaction: Il10-/- mice fed the cow and goat milk diets ate less and gained less weight than all the other diet groups. This diet effect was not evident for the C57BL/6J mice. Il10-/- mice on the cow and goat milk diets had reduced colon histological injury scores relative to those on the other diets. Il10-/- mice on the cow and goat milk diets also had reduced expression of many immune/inflammatory-related genes and pathways. 6x2 factorial design. Two strains of mouse (Il10 knockout mouse and the background strain C57BL/6J) were sampled at 12 weeks of age after feeding of milk, soy and control diets for 6 weeks, and intact proximal colon and colon epithelium harvested from each mouse (6 mice per group).