Normal Breast Milk Limits the Development of Colitis in IL-10-Deficient Mice.

Background And Aims: This study examined the role of breast milk in neonatal bacterial colonization of the colon and disease progression in IL-10-deficient mice.

Methods: IL-10-deficient mice were cross-fostered at birth and raised until weaning with a normal mother. Results were compared with normal pups cross-fostered to an IL-10-deficient mother. Mice were examined at various ages for histologic disease, levels of colonic bacteria, and proinflammatory cytokine secretion.

Results: IL-10-deficient mice that had been cross-fostered to a normal mother demonstrated normal levels of colonic adherent bacteria and reduced TNFalpha and IFN gamma secretion at 2 to 12 weeks of age. Histologic disease was significantly reduced up to 12 weeks of age. Normal mice cross-fostered to an IL-10-deficient mother had increased levels of adherent bacteria at 2 and 4 weeks and increased IFN gamma secretion. This group also demonstrated slight inflammation up until 12 weeks of age.

Conclusion: Breast milk has a role in neonatal bacterial colonization. Changing the luminal environment of IL-10-deficient mice during the neonatal period alters the natural disease course.