Characterisation of a canine epithelial cell line for modelling the intestinal barrier.

Little is known about how food interacts with the intestinal epithelium during the digestion process. However, it is known that ingredients in food can modulate the intestinal barrier, and have the potential to disrupt homeostasis of the gut. Here, we characterise a conditionally immortalised canine intestinal epithelial cell (cIEC) line for use in in vitro assays, to assess the effect of food ingredients on intestinal barrier function, permeability, cell health, and inflammation. Microscopy and flow cytometry confirmed that cIECs had a phenotype consistent with those of epithelial origin, and were able to differentiate to mature enterocytes. The cIECs also formed a monolayer when grown on Transwell® inserts, producing functional tight junctions between the cells. In contrast to the human-derived Caco-2 cell line, transepithelial electrical resistance (TEER) was increased in cIECs in response to two different raw ingredients. The exposure of cIECs to known inflammatory stimuli and raw ingredients induced the nuclear translocation of nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-?B). This work demonstrates the value of a unique cIEC in vitro model to study the effects of food ingredients on canine intestinal function and health, and supports continued efforts to reduce and refine the use of animals in scientific research.