Fh15 Reduces Colonic Inflammation and Leukocyte Infiltration in a Dextran Sulfate Sodium-Induced Ulcerative Colitis Mouse Model.

Ulcerative colitis (UC) is the most prevalent inflammatory bowel disease (IBD) in the USA. Current treatments present clinical limitations, underscoring the need for innovative therapeutics that promote an anti-inflammatory immune response. This study evaluates the anti-inflammatory potential of Fh15, a recombinant fatty acid binding protein, in a DSS-induced UC mouse model. Our results demonstrated that Fh15 treatment significantly ameliorated the severity of colitis by reducing the disease activity index (DAI) and histopathological scores. Moreover, Fh15 also decreased the serum levels of myeloperoxidase (MPO) and chitinase-3-like protein 1 (CHI3L1), and the expression of S100A9, a calcium and zinc binding protein, which is an important marker for the pathogenesis of UC. Furthermore, Fh15 downregulated pro-inflammatory cytokines TNFα and IL-1β in the distal colon, suggesting modulation of macrophage activity. Immunohistochemistry analysis revealed significantly reduced neutrophil and macrophage infiltration in UC Fh15-treated mice. These findings highlight the therapeutic potential of Fh15 for UC, as it modulates inflammatory responses, reduces leukocyte infiltration, and preserves colon integrity.