Colitis induced by 2,4,6-Trinitrobenzenesulfonic acid (TNBS) has been used as a model for Crohn's disease (CD) of inflammatory bowel disease (IBD). Lipocalin-2 (Lcn-2) is an emerging and clinically relevant biomarker of IBD. We investigated the performance of serum and fecal Lcn-2 in the TNBS model of colitis. Female, 7-week-old, BALB/c mice were administered intrarectally phosphate-buffered saline/water or 30% ethanol (vehicle control groups) for 5 days or TNBS for 5 days followed by a 28-day recovery phase. Serum and fecal levels of Lcn-2 were quantified, and effects on body weight, clinical scores, colon weight and length, gross pathology, and histopathology were investigated. Increased serum Lcn-2 levels correlated only with marked to severe inflammation. A clear differentiation in Lcn-2 fecal levels between TNBS-treated and vehicle-treated control mice was most noticeable on days 2 and 3. There was a strong correlation between body weight change, histopathologic scores of inflammation, and/or fecal Lcn-2 levels on days 2 and 5. Both serum and fecal Lcn-2 levels declined over time as the colonic mucosa recovered. Fecal Lcn-2 was found to be a more sensitive biomarker (vs. serum Lcn-2) and was able to discriminate mild, moderate, and severe colonic inflammation.
Keywords: Crohn’s disease; IBD; TNBS; biomarker; lipocalin-2.