Fig. 5.

Red 40 causes inflammation in the distal colon and rectum of the A/J mouse model. A/J mice were exposed to Red 40 in the drinking water (mouse equivalent of 7 mg/kg/d or 14 mg/kg/d) beginning at 3 months of age and continuing until 11 months of age. Because of the use of Red 40 in a high-fat, westernized diet; we also included groups consuming both a low-fat diet (LFD) and a high-fat diet (HFD). Flat structures, resembling aberrant crypt foci, were counted under a dissecting microscope in the proximal colon (A) and distal (B) colon/rectum. We then scored the inflammatory “histological” changes in the distal colon and rectum as we have done many times previously (C). Foci count in the distal colon and rectum were also quantified (D). We also stained for inducible nitric oxide synthase (iNOS) in the distal colon/rectum as a marker of inflammation (E). Finally, to see if Red 40 affects systemic inflammatory load, we measured serum IL-6; and saw that Red 40 indeed elevates the levels of IL-6 in the presence of a HFD (F). HFDR = High-Fat Diet + 1x Acceptable Daily Intake (ADI) Red 40; HFD2R = HFD + 2x ADI Red 40.

*, indicates significant difference (p < 0.05).