Abstract: Abstract:Objective To investigate the role of JNK in intestinal barrier dysfunction in severe septic mice treated by hydrogen. Methods Eighty male ICR mice were randomly divided into four groups (n=20 each):sham operation group, hydrogen control group, sepsis group and hydrogen treatment group. Severe sepsis rat model was reproduced by cecal ligation and puncture (CLP). Laparotomy without CLP was performed in sham operation group and hydrogen control group. The mice in hydrogen control group and hydrogen treatment group received 1-hour inhalation of 2% hydrogen at 1 hour and 6 hours after sham operation or CLP, respectively. Ten mice of each group were selected at 20 h after CLP operation and were gavaged with fluorescein- isothiocyanate- conjugated dextran (FITC- dextran). Blood samples were obtained by cardiac puncture to measure the serum concentration of FITC-dextran 4 h after treatment with FITC-dextran . Ten mice in each group were sacrificed at 24 h after CLP operation. The colony-forming unit (CFU) numbers in the peritoneal lavage fluid were counted. The middle intestinal tissues were obtained for the measurement of tumor necrosis factor alpha (TNF- α), interleukin (IL)-1β and high mobility group box 1(HMGB1) by ELISA. The level of phosphorylated JNK (p-JNK) and the expression of tight junction protein ZO- 1 and Occludin were detected by Western blot assay. The intestinal pathological changes and epithelial ultrastructure changes were observed by light microscope and transmission electron microscope(TEM). Results There was no statistical significance in clinical variables between sham operation group and hydrogen control group. Compared with sham operation group, the serum FITC- dextran concentration, the CFU numbers in the peritoneal lavage fluid, the levels of TNF-α, IL-1β and HMGB1 in intestine, and the expression of p-JNK were significantly increased, the expression of ZO-1 and Occludin were down-regulated in sepsis group（P < 0.05). There was a significant intestinal pathological injury along with epithelial ultrastrcture injury in sepsis group. Compared with sepsis group, the serum FITC-dextran concentration, the CFU numbers in the peritoneal lavage fluid, the levels of intestinal TNF- α, IL-1β and HMGB1, and the expression of p-JNK were significantly decreased, the expression of ZO-1 and Occludin were up-regulated in hydrogen treatment group（P < 0.05), and the pathological and ultrastructure damage was significantly reduced. Conclusion Hydrogen can decrease levels of proinflammatory factors and up-regulate the expression of tight junction to improve intestinal barrier dysfunction caused by severe sepsis, which is related with the inhibition of JNK signaling pathway

Key words: sepsis, hydrogen, JNK mitogen-activated protein kinases, intestinal mucosa, tumor necrosis factor-alpha, interleukin-1beta, high mobility group proteins, tight junction protein