Effect of hydrogen inhalation on acute lung injury in rats with sepsis

Objective To investigate the effect of hydrogen(H2) inhalation on acute lung injury in rats with sepsis.Methods Forty healthy male SD rats(weighing 200-250 g) were randomly divided into 4 groups(n = 10) using a random number table: sham operation group(SH group), cecal ligation and puncture group(CLP group), 1% H2 group, 2%H2group respectively. Sepsis model was produced by CLP. 1% H2 and 2% H2 group received 2 h inhalation of 1% H2 and 2% H2 at 12 h after CLP, respectively. At the end of hydrogen inhalation, blood samples were obtained for blood gas analysis. Pa O2/Fi O2 was calculated and the levels of high mobility group protein 1(HMGB1), interleukin-6(IL-6)were determined. The rats were then sacrificed and lungs were immediately removed for determination of the activity of Toll-like receptors-4(TLR-4), nuclear factor kappa B(NF-κB) and myeloperoxidase(MPO); pathology assessment of lung was done under light microscope. Results Compared with SH group, Pa O2/Fi O2 was significantly decreased, plasma levels of HMGB1, IL-6 increased, levels of TLR-4, NF-κB, MPO in lungs increased, and the pathological injury was significantly aggravated in CLP group, 1% H2 group and 2% H2group(P 0.05). Compared with CLP group, Pa O2/Fi O2 increased significantly, levels of HMGB1, IL-6 in plasma decreased markedly, levels of TLR-4, NF-κB, MPO in lungs decreased, and the pathological injury was reduced in 1% H2 group and 2% H2group(P 0.05). There were no significant differences of the above indexes between 1% H2 group and 2% H2group(P 0.05). Conclusion Hydrogen inhalation can alleviate sepsis induced ALI in rats, and its mechanism may be related to inhibiting inflammatory response.