Abstract 2930: Baicalein attenuates radiation-induced enteritis by improving endothelial dysfunction

Background: Radiation-induced intestinal injury is frequently observed following clinical application of radiation for abdominal and pelvic cancers or occurs secondary to radiation exposure following a nuclear accident. Radiation-induced enteritis may be considered an ideal model of gastrointestinal inflammation. The endothelium is a crucial component of inflammation, and the endothelial dysfunction following radiation exposure induces the intestinal proinflammatory response and progression of radiation enteritis. Baicalein (5,6,7-trihydroxyflavonoid) is a flavonoid from Scutellaria baicalensis used in oriental herbal medicine. Baicalein has been found to have multiple beneficial properties including antioxidant, anti-inflammatory, anti-allergic, and anti-cancer activities. Here, we investigated the therapeutic effects of baicalein on endothelial dysfunction in radiation-induced intestinal inflammation. Methods: We performed histological analysis, bacterial translocation assays, and intestinal permeability assays, and also assessed infiltration of leukocytes and inflammatory cytokine expression using a radiation-induced enteritis model. In addition, to investigate the effect of baicalein in endothelial dysfunction, we analyzed endothelial-derived adherent molecules in human umbilical vein endothelial cells and irradiated intestinal tissue. Results: Histological damage such as shortening of villi length and impaired intestinal crypt function was observed in the radiation-induced enteritis model. However, intestinal damage was attenuated in baicalein-treated groups with improvement of intestinal barrier function. Baicalein inhibited the expression of radiation-induced adherent molecules in the endothelial cells and increased leukocyte infiltration in the irradiated intestine. We also determined that baicalein could accelerate crypt regeneration via recovery of endothelial damage. Conclusions: Baicalein has a therapeutic effect on radiation-induced intestinal inflammation by attenuating endothelial damage. Citation Format: Hyosun Jang, Sunhoo Park, Sehwan Shim, Jae Kyung Myung. Baicalein attenuates radiation-induced enteritis by improving endothelial dysfunction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2930.