Effects of kiwifruit extracts on colonic gene and protein expression levels in IL-10 gene-deficient mice

Inflammatory bowel disease (IBD) is a collective term for conditions characterised by chronic inflammation of the gastrointestinal tract involving an inappropriate immune response to commensal micro-organisms in a genetically susceptible host. Previously, aqueous and ethyl acetate extracts of gold kiwifruit (Actinidia chinensis) or green kiwifruit (A. deliciosa) have demonstrated anti-inflammatory activity usingin vitromodels of IBD. The present study examined whether these kiwifruit extracts (KFE) had immune-modulating effectsin vivoagainst inflammatory processes that are known to be increased in patients with IBD. KFE were used as a dietary intervention in IL-10-gene-deficient (Il10− / −) mice (anin vivomodel of IBD) and the C57BL/6J background strain in a 3 × 2 factorial design. While allIl10− / −mice developed significant colonic inflammation compared with C57BL/6J mice, this was not affected by the inclusion of KFE in the diet. These findings are in direct contrast to our previous study where KFE reduced inflammatory signalling in primary cells isolated fromIl10− / −and C57BL/6J mice. Whole-genome gene and protein expression level profiling indicated that KFE influenced immune signalling pathways and metabolic processes within the colonic tissue; however, the effects were subtle. In particular, expression levels across gene sets related to adaptive immune pathways were significantly reduced using three of the four KFE in C57BL/6J mice. The present study highlights the importance of investigating food components identified by cell-based assays with appropriatein vivomodels before making dietary recommendations, as a food that looks promisingin vitromay not be effectivein vivo.