Bioluminescence imaging for IL-1β expression in experimental colitis

Background Interleukin 1 beta (IL-1β) contributes to the development of inflammatory bowel disease (IBD) and is correlated with the severity of intestinal inflammation. However, the precise source of IL-1β producing cells in DSS colitis is currently not known. Methods To determine IL-1β activity during intestinal inflammation in real time, an IL-1β transgenic mouse has been generated by incorporating the firefly luciferase gene driven by a 4.5-kb fragment of human IL-1β gene promoter (named cHS4I-hIL-1βP-Luc transgenic mice). Dextran sodium sulfate (DSS) induced colitis was confirmed with clinical presentation and histopathology. Results A substantial increase in luciferase activity (reflecting IL-1β production) in the region of inflamed colon was observed in a time dependent manner, followed by additional activity in the region of the mesenteric lymph node. The up-regulated luciferase activity was suppressed by dexamethasone (steroids) during DSS challenge, consistent with reduced severity of colitis, confirming the specificity of luciferase activity. Conclusions Our data suggests that bioluminescence is an interesting technology, which may be used to evaluate transcription of various genes in real time in experimental colitis.