Role of Rho/ROCK signaling pathway in the protective effects of hydrogen against acute lung injury in septic mice

Results: There was no statistical difference in the above indexes between the sham surgery group and the H2 control group.Compared with the sham surgery group,the sepsis group demonstrated significant increases in the concentrations of protein, TNF-α,IL-1 β and PMN counts in BALF, the lung EB and MDA content, W/D ratio, the ratio of Rho-GTP/total Rho,the expressions of ROCK1 and ROCK2,the ratio of phosphorylated-myosine phosphatae targeting subunit 1 (p-MYPT1)/MYPT1,and significant decreases in the lung SOD activity and ZO-1 expression. Compared with the sepsis group, the H2 treatment group showed statistically significant decreases in the concentrations of protein, TNF-α,IL-1 β,PMN counts in BALF [protein (g/L):3.12 ± 0.33 vs.6.37±0.56,TNF-o(ng/L):128.45± 17.33 vs.563.83±61.72,IL-1β (ng/L):75.76± 14.35 vs.245.52±30.56,PMN counts (× 105/L):7.46± 1.34 vs.18.55± 5.73],and permeability of lung [EB concentration (μg/g):73.33±6.98vs.144.83± 12.38],the lung MDA content (mmol/g:3.66±0.53 vs.6.04± 1.13),the lung W/D ratio (5.02± 0.34 vs.7.26 ±0.56),the ratio of Rho-GTP/total Rho, the expressions of ROCK1 and ROCK2,the ratio of p-MYPT1/MYPT1 [Rho-GTP/total Rho:(43.12 ± 4.69)％ vs.(68.82± 5.44)％,ROCK1 (gray value):2.42 ± 0.42 vs.6.03 ± 0.64,ROCK2(gray value):2.56± 0.52 vs.4.85 ± 0.53,p-MYPT1/MYPT1:(57.83 ± 8.67)％ vs.(112.50± 13.43)％],and statistically significant increases in the lung SOD activity (kU/g:18.58± 1.68 vs.13.31±2.20) as well as the expression of ZO-1 (gray value:0.61 ± 0.07 vs.0.32 ± 0.06,fluorescence intensity:0.77 ± 0.06 vs.0.54 ± 0.05;all P ＜ 0.05). Moreover, lung HE staining showed that there were obvious lung injuries in the sepsis group which were alleviated in the H2 treatment group.

Conclusion: H2 could improve endothelial permeability and suppress inflammation and oxidative stress to alleviate ALI in septic mice through inhibition of Rho/ROCK signaling pathway.