Change of Intestinal Microbiota with Elemental Diet and Its Impact on Therapeutic Effects in a Murine Model of Chronic Colitis

Abstract

Elemental diet (ED) has been used as an enteral nutritional therapy for Crohn's disease. However, the precise mechanisms of ED remain unclear. In interleukin-10 (IL-10)-deficient cell-transferred mice, we investigated the change of intestinal microbiota with ED using molecular terminal-restriction fragment length polymorphism (T-RFLP) analysis and culture method, and evaluated its influence on therapeutic effects of ED. ED significantly suppressed intestinal inflammation. The total amount of bacteria in colitis mice fed the regular diet was higher than in normal mice but decreased in colitis mice fed ED. T-RFLP profiles of the ED group markedly differed from those of the regular diet groups. The diversity of bacterial species in the ED group decreased to 60% of that found in the regular diet groups. Among the cultivated bacteria, the change in lactic acid bacteria composition was remarkable. Lactobacillus reuteri and L. johnsonii decreased and Enterococcus faecalis and E. durans increased in the ED group. The culture supernatant of L. reuteri isolates induced significant tumor necrosis factor-alpha (TNF-alpha) and IL-6 activity in RAW 264 cells, while the culture supernatant of E. faecalis and E. durans barely induced their activity. These data suggested that reduction in amount and diversity of intestinal microbiota and decrease of proinflammatory cytokines via a change in composition of lactic acid bacteria by ED seem to contribute to reduction of bowel inflammation in this model.