Effect of inhalation of hydrogen mixed with hyperoxia on acute lung injury in septic mice

Abstract

Objective To investigate the effect of inhalation of hydrogen mixed with hyperoxia on acute lung injury in septic mice. Methods One hundred and thirty adult male C57BL/6 mice, weighing 20-25 g, were randomly divided into 5 groups(n=26 each)using a random number table: sham operation group(group Sham); sepsis induced by cecal ligation and puncture(CLP)group(group CLP); hyperoxia group(group O2); hydrogen group(group H2); hydrogen plus hyperoxia group(H2+ O2 group). Sepsis was produced by CLP.At 1 and 6 h after CLP, 2% hydrogen, 98% oxygen and the mixture of 21% oxygen and 79% nitrogen were inhaled for 3 h in H2, O2 and H2+ O2 groups, respectively, and the mixture of 21% oxygen and 79% nitrogen was inhaled for 3 h in Sham and CLP groups.Twenty mice in each group were selected, and the survival rates within 7 days after CLP or sham operation were recorded.The left 6 mice in each group were selected, and the animals were sacrificed at 24 h after CLP or sham operation.The right lung was lavaged, and broncho-alveolar lavage fluid(BALF)was collected for determination of the protein concentrations.The lungs were removed for examination of the pathological changes and for determination of the wet to dry weight ratio(W/D ratio), activities of superoxide dismutase(SOD)and catalase(CAT)and 8-isoprostaglandin F2α(8-iso-PGF2α)content in lung tissues. Results Compared with group Sham, the survival rates were significantly decreased, the pathological score, W/D ratio and protein concentrations in BALF were significantly increased, the SOD and CAT activities were significantly decreased, and the 8-iso-PGF2α content was significantly increased in CLP, O2 and H2 groups, and the pathological score and protein concentrations in BALF were significantly increased, the SOD and CAT activities were significantly decreased, the 8-iso-PGF2α content was significantly increased(P 0.05). Compared with group CLP, the survival rates were significantly increased, the pathological score, W/D ratio and protein concentrations in BALF were significantly decreased, the SOD and CAT activities were significantly increased, and the 8-iso-PGF2α content was significantly decreased in O2, H2 and H2+ O2 groups(P<0.05). Compared with group O2 or group H2, the survival rates were significantly increased, the pathological score, W/D ratio and protein concentrations in BALF were significantly decreased, the SOD and CAT activities were significantly increased, and the 8-iso-PGF2α content was significantly decreased in group H2+ O2(P<0.05). Conclusion Inhalation of hydrogen mixed with hyperoxia provides better efficacy than either alone in reducing acute lung injury in septic mice. Key words: Hydrogen; Oxygen; Sepsis; Respiratory distress syndrome, adult