Gut bacteria are required for the benefits of black raspberries in Apc Min/+ mice.

Abstract

The gut microbiota plays a pivotal role in the development of inflammatory bowel disease and colorectal cancer. To determine whether the gut microbiota is required for the chemoprotective effects of black raspberries (BRBs) in Apc Min/+ mice. Apc Min/+ mice were given (a) a control diet for 8 weeks, or (b) the control diet for 4 weeks and then a 5% BRB diet for additional 4 weeks, or (c) the control diet and antibiotics for 4 weeks followed by the 5% BRB diet and antibiotics for the next 4 weeks. At the end of the study, all the mice were euthanized, and colonic and intestinal polyps were counted. mRNA expression levels of TLR4, NF-κB1, and COX2 were determined in colon and small intestine of these Apc Min/+ mice by quantitative real-time PCR. 5% BRBs significantly suppressed intestinal and colonic polyp development in the Apc Min/+ mice, whereas antibiotics significantly abolished BRBs' chemoprotective effects. BRBs decreased mRNA levels of TLR4, NF-κB1, and COX2 in colon, whereas significantly enhanced mRNA levels of TLR4 and NF-κB1 were observed in small intestine of BRB-treated Apc Min/+ mice fed antibiotics. The gut microbiota is required for BRBs' chemoprotection against polyp development in Apc Min/+ mice.