Ulinastatin mediates protection against vascular hyperpermeability following hemorrhagic shock.

OBJECT Recent studies have suggested that intrinsic apoptotic signaling cascade is involved in endothelial barrier dysfunction following hemorrhagic shock (HS), which results in vascular hyperpermeability. Our previous study demonstrated that ulinastatin (UTI) inhibits oxidant-induced endothelial hyperpermeability and apoptotic signaling. In present study, we hypothesized that UTI would improve HS-induced vascular hyperpermeability by regulating the intrinsic apoptotic signaling cascade. METHODS Hemorrhagic shock was induced in rats by withdrawing blood to reduce the mean arterial pressure to 40-45 mmHg for 60 min, followed by reperfusion. Mesenteric postcapillary venules were examined for changes in hyperpermeability by intravital microscopy. In vitro, Rat lung microvascular endothelial cells (RLMVECs) were exposed in hemorrhagic shock serum for 120 min, followed by transendothelial electrical resistance (TER) estimation. Mitochondrial release of cytochrome c and caspase-3 activation was estimated in vivo. In vitro, ratio of cell apoptosis was evaluated by Annexin-V/PI double stain assay; mitochondrial membrane potential (∆Ψm) was determined with JC-1; intracellular ATP content was assayed by a commercial kit; reactive oxygen species (ROS) was measured by DCFH-DA; adherens junction protein β-catenin was detected by immunofluorescense staining. RESULTS In vivo, UTI attenuated HS-induced vascular hyperpermeability versus the HS group (P < 0.05); In vitro, UTI attenuated shock serum induced RLMEC monolayer hyperpermeability (P < 0.05). In vivo, UTI inhibited HS-induced cytochrome c release and caspase-3 activation (P < 0.05). In vitro, shock serum induced cell apoptosis, low ATP level, ∆Ψm depolarization, ROS increase were improved by UTI pre-treatment (P < 0.05). UTI improved shock serum induced disruption of endothelial cell adherens junction. CONCLUSIONS UTI inhibits vascular hyperpermeability following HS. UTI regulates oxidative stress and intrinsic apoptotic signaling following HS.