Hydrogen alleviated organ injury and dysfunction in sepsis: The role of cross-talk between autophagy and endoplasmic reticulum stress: Experimental research.

AIMS: Sepsis is defined as a life-threatening organ dysfunction that is caused by a dysregulated host response to infection. Although much progress has been made in understanding the pathophysiology of sepsis, further discussion and study of the detailed therapeutic mechanisms are needed. Autophagy and endoplasmic reticulum stress are two pathways of the complicated regulatory network of sepsis. Herein, we focus on the cellular mechanism in which autophagy and endoplasmic reticulum stress participate in hydrogen (H2)-protected sepsis-induced organ injury. MATERIALS AND METHODS: Male C57BL/6 mice were randomly divided into the following groups: control group, cecal ligation puncture (CLP) group, CLP + tunicamycin(TM) group, CLP + 4-phenyl butyric acid (4-PBA) group, CLP + rapamycin (Rap) group, CLP + 3-methyladenine (3-MA) group, CLP + H2 group, CLP + H2 + 3-MA group, and CLP + H2 + TM group. After the experiment was completed, autophagosome was detected by transmission electron microscopy; protein PKR-like ER kinase (PERK), p-PERK, Eukaryotic translation initiation factor-2α (eIF2α), p-eIF2α, inositol-requiring enzyme1α(IRE1α), C/EBP homologous protein(CHOP), activating transcription factor(ATF), XBP-1, microtubule-associated protein 1 light(LC3), Beclin1, PTEN-induced putative kinase 1(PINK1), Parkin, and p65 subunit of Nuclear factor kappa B(NF-κb) were measured by Western blot; myeloperoxidase(MPO) activity in lung, bronchoalveolar lavage(BAL) total protein, lung wet-to-dry(W/D) ratio, serum biochemical indicators, 7-day survival rate, and pathological injury scores of lung, liver, and kidney were tested; and cytokines tumor necrosis factor-α(TNF-α), Interleukin(IL)-1ß, and IL-6 and high mobility group box protein (HMGB)1 were detected by enzyme-linked immunosorbent assay(ELISA). RESULTS: We demonstrated that sepsis induced endoplasmic reticulum stress. Moreover, it was found that an increase in endoplasmic reticulum impaired autophagy activity in sepsis, and the absence of endoplasmic reticulum stress attenuated tissue histological injury and dysfunction of lung, liver, and kidney in septic mice. Intriguingly, hydrogen alleviated the endoplasmic reticulum stress via the autophagy pathway and also mitigated inflammation and organ injury. CONCLUSION: Hydrogen provided protection from organ injury induced by sepsis via autophagy activation and endoplasmic reticulum stress pathway inactivation.

Hydrogen-rich saline improves survival and neurological outcome after cardiac arrest and cardiopulmonary resuscitation in rats.

BACKGROUND: Sudden cardiac arrest is a leading cause of death worldwide. Three-fourths of cardiac arrest patients die before hospital discharge or experience significant neurological damage. Hydrogen-rich saline, a portable, easily administered, and safe means of delivering hydrogen gas, can exert organ-protective effects through regulating oxidative stress, inflammation, and apoptosis. We designed this study to investigate whether hydrogen-rich saline treatment could improve survival and neurological outcome after cardiac arrest and cardiopulmonary resuscitation, and the mechanism responsible for this effect. METHODS: Sprague-Dawley rats were subjected to 8 minutes of cardiac arrest by asphyxia. Different doses of hydrogen-rich saline or normal saline were administered IV at 1 minute before cardiopulmonary resuscitation, followed by injections at 6 and 12 hours after restoration of spontaneous circulation, respectively. We assessed survival, neurological outcome, oxidative stress, inflammation biomarkers, and apoptosis. RESULTS: Hydrogen-rich saline treatment dose dependently improved survival and neurological function after cardiac arrest/resuscitation. Moreover, hydrogen-rich saline treatment dose dependently ameliorated brain injury after cardiac arrest/resuscitation, which was characterized by the increase of survival neurons in hippocampus CA1, reduction of brain edema in cortex and hippocampus, preservation of blood-brain barrier integrity, as well as the decrease of serum S100ß and neuron-specific enolase. Furthermore, we found that the beneficial effects of hydrogen-rich saline treatment were associated with decreased levels of oxidative products (8-iso-prostaglandin F2α and malondialdehyde) and inflammatory cytokines (tumor necrosis factor-α, interleukin-1ß, and high-mobility group box protein 1), as well as the increased activity of antioxidant enzymes (superoxide dismutase and catalase) in serum and brain tissues. In addition, hydrogen-rich saline treatment reduced caspase-3 activity in cortex and hippocampus after cardiac arrest/resuscitation. CONCLUSIONS: Hydrogen-rich saline treatment improved survival and neurological outcome after cardiac arrest/resuscitation in rats, which was partially mediated by reducing oxidative stress, inflammation, and apoptosis.

Heme oxygenase-1 mediates the anti-inflammatory effect of molecular hydrogen in LPS-stimulated RAW 264.7 macrophages.

BACKGROUND: Molecular hydrogen (H2) as a new medical gas has an anti-inflammatory effect. In the present study, we investigated whether heme oxygenase-1 (HO-1) contributes to the anti-inflammatory effect of H2 in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. METHODS: RAW 264.7 macrophages were stimulated by LPS (1 µg/mL) with presence or absence of different concentrations of H2. Cell viability and injury were tested by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay and lactate dehydrogenase (LDH) release, respectively. The cell culture supernatants were collected to measure inflammatory cytokines [TNF-α, IL-1ß, HMGB1 (high mobility group box-1) and IL-10] at different time points. Moreover, HO-1 protein expression and activity were tested at different time points. In addition, to further identify the role of HO-1 in this process, zinc protoporphyrin (ZnPP)-IX, an HO-1 inhibitor, was used. RESULTS: H2 treatment had no significant influence on cell viability and injury in normally cultured RAW 264.7 macrophages. Moreover, H2 treatment dose-dependently attenuated the increased levels of pro-inflammatory cytokines (TNF-α, IL-1ß, HMGB1), but further increased the level of anti-inflammatory cytokine IL-10 at 3 h, 6 h, 12 h and 24 h after LPS stimulation. Furthermore, H2 treatment could also dose-dependently increase the HO-1 protein expression and activity at 3 h, 6 h, 12 h and 24 h in LPS-activated macrophages. In addition, blockade of HO-1 activity with ZnPP-IX partly reversed the anti-inflammatory effect of H2 in LPS-stimulated macrophages. CONCLUSIONS: Molecular hydrogen exerts a regulating role in the release of pro- and anti-inflammatory cytokines in LPS-stimulated macrophages, and this effect is at least partly mediated by HO-1 expression and activation.

[Regulative effects of hydrogen-rich medium on monocytic adhesion and vascular endothelial permeability].

OBJECTIVE: To explore the regulative effects of hydrogen-rich medium on lipopolysaccharide (LPS)-induced monocytes adhesion to human umbilical vein endothelial cells (HUVEC) and vascular endothelial permeability in vitro. METHODS: Endothelial cells were seeded in 6-well plates and randomly divided into 4 groups (n = 42 each):control (A), hydrogen-rich medium (B), LPS (C) and LPS+hydrogen-rich medium (D). Cells were cultured in plain culture medium in groups A and C or in hydrogen-saturated culture medium in groups B and D.LPS 1 µg/ml was added into groups C and D.When forming a monolayer, monocytes were added into each group after 6, 12 and 24 h respectively. After a 90-minute co-culturing, adhesion status was detected by Wright-Giemsa stain.Supernatants were collected to detect the concentrations of vascular cell adhesion molecule-1 (VCAM-1) and E-selectin by enzyme-linked immunosorbent assay (ELISA). The expression of VE-cadherin was measured by Western blot. Cells were stained with immunofluorescence to show the distribution of VE-cadherin after a 24-hour incubation. RESULTS: Compared with group A, the adhesion of monocytes to endothelial cells increased (P < 0.05) in group C, the levels of E-selectin and VCAM-1 became elevated (P < 0.05) while the expression of VE-cadherin decreased significantly (P < 0.05). Compared with group C, adhesion decreased in group D (P < 0.05), the levels of E-selectin and VCAM-1 decreased (P < 0.05) while there was an increased expression of VE-cadherin (P < 0.05). Three timepoints showed the same tendency. The results of 24 h fluorescence indicated that, compared with group A, VE-cadherin was incomplete in cell-cell connections in group C.However it was complete and well-distributed in group D versus group C. CONCLUSION: Hydrogen-rich medium may reduce the LPS-induced release of adhesion molecules, lessen monocytic adhesion to HUVEC and regulate the expression of VE-cadherin to protect vascular permeability.