Abstract: AIM: To explore the protective effect and mechanism of dexmedetomidine on intestinal mucosal barrier injury in septic rats.  METHODS: Forty eight SD rats were randomly divided into four groups (n=12): sham operation group (sham group), sepsis group (sepsis group), sepsis + dexmedetomidine group (DEX group), and sepsis + DEX + HIF-1ɑ inhibitor Bay87-2243 (Bay87-2243 group). Sepsis model was established by cecal ligation and perforation (CLP). The rats in both DEX and Bay87-2243 groups were given 30 μg/kg of DEX intraperitoneally 30 minutes before CLP and 2 hours after CLP; while the rats in Bay87-2243 group received oral gavage of Bay87-2243 (9 mg/kg) for 3 days before CLP. The other groups were intraperitoneally injected and orally with the same amount of normal saline. The HIF-1ɑ and the tight junction protein (tight junction protein, TJs) was detected by western blot; the plasma concentrations of diamine oxidase (DAO), intestinal fatty acid binding protein (FABP2) and D-lactic acid (D-LAC) were detected by ELISA; the morphological changes of intestinal mucosa were detected by HE staining. RESULTS: DEX significantly increased the expression level of HIF-1ɑ (P<0.05) on intestinal mucosa in rats with sepsis injury (P<0.05), thus ameliorated intestinal mucosal pathological injury, reduced Chiu's score (P<0.05), decreased intestinal mucosal permeability (P<0.05), and up-regulated TJS protein expression (P<0.05). Moreover, effect on sepsis induced intestinal mucosal injury of DEX was reversed by HIF-1ɑ Bay87-2243. CONCLUSION: DEX could protect against sepsis-induced intestinal mucosal injury by up-regulating HIF-1ɑ expression in rats.

Key words: sepsis, dexmetomidine, hypoxia inducible factor-1ɑ, tight junction protein, intestinal mucosal permeability