Inflammatory bowel diseases (IBDs) are devastating conditions of the gastrointestinal tract with limited treatments, and dietary intervention may be effective and affordable for managing symptoms.
Glucosinolate compounds are highly concentrated in broccoli sprouts, especially
glucoraphanin (GLR), and can be metabolized by certain mammalian gut bacteria into anti-inflammatory
isothiocyanates, such as
sulforaphane. Gut microbiota exhibit biogeographic patterns, but it is unknown if
colitis alters these or whether the location of
glucoraphanin-metabolizing bacteria affects anti-inflammatory benefits. We fed specific pathogen-free C57BL/6 mice either a control diet or
a 10% steamed broccoli sprout diet and gave a three-cycle regimen of 2.5%
dextran sodium sulfate (DSS) in
drinking water over a 34-day experiment to simulate chronic, relapsing
ulcerative colitis (UC). We monitored
body weight, fecal characteristics,
lipocalin, serum
cytokines, and bacterial communities from the
luminal- and mucosal-associated populations in the jejunum, cecum, and colon. Mice fed the broccoli sprout diet with DSS treatment performed better than mice fed the control diet with DSS, and had significantly more
weight gain, lower Disease Activity Index scores, lower plasma
lipocalin and proinflammatory
cytokines, and higher bacterial richness in all gut locations. Bacterial communities were assorted by gut location but were more homogenous across locations in the control diet + DSS mice. Importantly, our results showed that broccoli sprout feeding abrogated the effects of DSS on gut microbiota, as bacterial richness and biogeography were similar between mice receiving broccoli sprouts with and without DSS. Collectively, these results support the protective effect of steamed broccoli sprouts against
dysbiosis and
colitis induced by DSS. IMPORTANCE Evaluating bacterial communities across different locations in the gut provides a greater insight than fecal samples alone and provides an additional metric by which to evaluate beneficial host-microbe interactions. Here, we show that 10% steamed broccoli sprouts in the diet protects mice from the negative effects of
dextran sodium sulfate-induced
colitis, that
colitis erases biogeographic patterns of bacterial communities in the gut, and that the cecum is not likely to be a significant contributor to colonic bacteria of interest in the DSS mouse model of
ulcerative colitis. Mice fed the broccoli sprout diet during
colitis performed better than mice fed the control diet while receiving DSS. The identification of accessible dietary components and concentrations that help maintain and correct the gut microbiome may provide universal and equitable approaches to IBD prevention and recovery, and broccoli sprouts represent a promising strategy.