Telmisartan loading thermosensitive hydrogel repairs gut epithelial barrier for alleviating inflammatory bowel disease

Inflammatory bowel disease (IBD) remains a global health concern with a complex and incompletely understood pathogenesis. In the course of IBD development, damage to intestinal epithelial cells and a reduction in the expression of tight junction (TJ) proteins compromise the integrity of the intestinal barrier, exacerbating inflammation. Notably, the renin-angiotensin system and angiotensin II receptor type 1 (AT1R) play a crucial role in regulating the pathological progression including vascular permeability, and immune microenvironment. Thus, Telmisartan (Tel), an AT1R inhibitor, loading thermosensitive hydrogel was constructed to investigate the potential of alleviating inflammatory bowel disease through rectal administration. The constructed hydrogel exhibits an advantageous property of rapid transformation from a solution to a gel state at 37°C, facilitating prolonged drug retention within the gut while mitigating irritation associated with rectal administration. Results indicate that Tel also exhibits a beneficial effect in ameliorating colon shortening, colon wall thickening, cup cell lacking, crypt disappearance, and inflammatory cell infiltration into the mucosa in colitis mice. Moreover, it significantly upregulates the expression of TJ proteins in colonic tissues thereby repairing the intestinal barrier damage and alleviating the ulcerative colitis (UC) disease process. In conclusion, Tel-loaded hydrogel demonstrates substantial promise as a potential treatment modality for IBD.