Objective To investigate the therapeutic effect and mechanism of hydrogen (H2) on collagen-induced arthritis (CIA) in mice. Methods DBA/1 mice were randomly divided into normal control group, CIA group and CIA mice treated with H2 group (H2 treated group), with 6 mice in each group. Following the preparation of CIA mouse model, the H2 treated group received H2 inhalation therapy (300 mL/L, 3 hours/d) for 15-60 days. The arthritis score were assessed and HE staining of joint were evaluated by referring to the pathology score; The number of CD4+IL-22+ cells in spleen and joint was observed by flow cytometry and immunohistochemical staining; ELISA was conducted to assess the levels of interleukin 22 (IL-22) in serum and joint; Western blotting was performed to examine the expression of phosphorylated STAT3 (p-STAT3) and phosphorylated NF-κB (p-NF-κB) in joint between the three groups. Results In the CIA group, both the arthritis score and pathology score were higher than control group, while they dropped after H2 treatment. In addition, compared with control group, CIA group showed higher proportion of CD4+IL-22+ cells and higher level of IL-22 which then interestingly decreased after H2 therapy. Besides, the p-STAT3 and p-NF-κB were elevated in CIA mice compared with control group, and H2 treatment significantly inhibited them. Conclusion H2 can reduce the levels of CD4+IL-22+ cells and IL-22, and alleviate arthritis symptoms in CIA mice by inhibiting STAT3/NF-κB pathway.
Endotoxins and other harmful substances may cause an increase in permeability in endothelial cells (ECs) monolayers, as well as ECs shrinkage and death to induce lung damage. Lipopolysaccharide (LPS) can impair endothelial progenitor cells (EPCs) functions, including proliferation, migration, and tube formation. EPCs can migrate to the damaged area, differentiate into ECs, and participate in vascular repair, which improves pulmonary capillary endothelial dysfunction and maintains the integrity of the endothelial barrier. Hydrogen (H2) contributes to the repairment of lung injury and the damage of ECs. We therefore speculate that H2 protects the EPCs against LPS-induced damage, and it’s mechanism will be explored. The bone marrow-derived EPCs from ICR Mice were treated with LPS to establish a damaged model. Then EPCs were incubated with H2, and treated with PI3K inhibitor LY294002 and endothelial nitric oxide synthase (eNOS) inhibitor L-NAME. MTT assay, transwell assay and tube formation assay were used to detect the proliferation, migration and angiogenesis of EPCs. The expression levels of target proteins were detected by Western blot. Results found that H2 repaired EPCs proliferation, migration and tube formation functions damaged by LPS. LY294002 and L-NAME significantly inhibited the repaired effect of H2 on LPS-induced dysfunctions of EPCs. H2 also restored levels of phosphor-AKT (p-AKT), eNOS and phosphor-eNOS (p-eNOS) suppressed by LPS. LY294002 significantly inhibited the increase of p-AKT and eNOS and p-eNOS expression exposed by H2. L-NAME significantly inhibited the increase of eNOS and p-eNOS expression induced by H2. H2 repairs the dysfunctions of EPCs induced by LPS, which is mediated by PI3K/AKT/eNOS signaling pathway.