Hydrogen-rich saline protects against liver injury in rats with obstructive jaundice

Hydrogen Protection Boosts the Bioactivity of Chrysanthemum morifolium Extract in Preventing Palmitate-Induced Endothelial Dysfunction by Restoring MFN2 and Alleviating Oxidative Stress in HAEC Cells

As the most important natural antioxidants in plant extracts, polyphenols demonstrate versatile bioactivities and are susceptible to oxidation. The commonly used ultrasonic extraction often causes oxidation reactions involving the formation of free radicals. To minimize the oxidation effects during the ultrasonic extraction process, we designed a hydrogen (H₂)-protected ultrasonic extraction method and used it in Chrysanthemum morifolium extraction. Hydrogen-protected extraction improved the total antioxidant capacity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and polyphenol content of Chrysanthemum morifolium water extract (CME) compared with air and nitrogen (N₂) conditions. We further investigated the protective effects and mechanisms of CME on palmitate (PA)-induced endothelial dysfunction in human aorta endothelial cells (HAECs). We found that hydrogen-protected CME (H₂-CME) best-prevented impairment in nitric oxide (NO) production, endothelial NO synthase (eNOS) protein level, oxidative stress, and mitochondrial dysfunction. In addition, H₂-CME prevented PA-induced endothelial dysfunction by restoring mitofusin-2 (MFN2) levels and maintaining redox balance.

FAT10 promotes hepatocellular carcinoma (HCC) carcinogenesis by mediating P53 degradation and acts as a prognostic indicator of HCC

Background

With the advancement of hepatocellular carcinoma (HCC) treatment technology, the treatment options for HCC patients have increased. However, due to high heterogeneity, among other reasons, the five-year survival rate of patients is still very low. Currently, gene expression prognostic models can suggest more appropriate strategies for the treatment of HCC. This study investigates the role of FAT10 in hepatocarcinogenesis and its underlying mechanism.

Methods

The expression of FAT10 was detected by immunohistochemical method using tissue arrays containing 4 specimens of patients with digestive cancer. The expression of FAT10 was determined by a tissue microarray which included 286 pairs of HCC samples and corresponding normal mucosae and was further confirmed by real-time polymerase chain reaction (PCR) and western blot. The Kaplan-Meier survival curve was used to determine the correlation of FAT10 expression with patients' recurrence and overall survival (OS) rate. In vivo, liver fibrosis, cirrhosis, and HCC models were established to assess the FAT10 expression. Moreover, FAT10 over-expressing cell lines were used to determine the molecular mechanism underlying the FAT10-induced cell proliferation and hepatocarcinogenesis by reporter gene measure, real-time PCR, and western blot. Based on TCGA database, signal pathways associated with FAT10 and HCC invasion and metastasis were analyzed by KEGG enrichment analyze.

Results

Overexpression of FAT10 in HCC was observed in this study compared with its expression in other digestive tumors. Clinicopathological analysis revealed that FAT10 expression levels were closely associated with tumor diameters and poor prognosis of HCC. This study also confirmed through in vivo experiments that the expression of FAT10 in liver fibrosis, cirrhosis, and HCC gradually increases. Further study revealed that forced FAT10 expression enhanced the growth ability of HCC cells and mediated the degradation of the critical anti-cancer protein p53, which led to carcinogenesis. Finally, 9 signal pathways related to HCC metastasis were obtained through bioinformatics analysis.

Conclusions

FAT10 may act as a proto-oncogene that facilitates HCC carcinogenesis by mediating p53 degradation, and the expression of FAT10 is negatively correlated with the prognosis of HCC patients. FAT10 is expected to become a potential combined target and prognostic warning marker for HCC treatment.

Molecular Hydrogen as a Novel Protective Agent against Pre-Symptomatic Diseases

Mibyou, or pre-symptomatic diseases, refers to state of health in which a disease is slowly developing within the body yet the symptoms are not apparent. Common examples of mibyou in modern medicine include inflammatory diseases that are caused by chronic inflammation. It is known that chronic inflammation is triggered by the uncontrolled release of proinflammatory cytokines by neutrophils and macrophages in the innate immune system. In a recent study, it was shown that molecular hydrogen (H2) has the ability to treat chronic inflammation by eliminating hydroxyl radicals (·OH), a mitochondrial reactive oxygen species (ROS). In doing so, H2 suppresses oxidative stress, which is implicated in several mechanisms at the root of chronic inflammation, including the activation of NLRP3 inflammasomes. This review explains these mechanisms by which H2 can suppress chronic inflammation and studies its applications as a protective agent against different inflammatory diseases in their pre-symptomatic state. While mibyou cannot be detected nor treated by modern medicine, H2 is able to suppress the pathogenesis of pre-symptomatic diseases, and thus exhibits prospects as a novel protective agent.

Hydrogen treatment: a novel option in liver diseases

Hydrogen therapy is a very promising treatment against several diseases due to its mild attributes, high affinity and inherent biosafety. However, there is little elaboration about current hydrogen treatment in liver diseases. This article introduces the administration of hydrogen and mechanisms of hydrogen therapy in vivo, including modulating reactive oxygen species, apoptosis and autophagy, and inflammation, affecting mitochondria, as well as protein transporters. The major focus is clinical hydrogen use and related mechanisms in liver dysfunction or diseases, including non-alcoholic fatty liver disease, hepatitis B, liver dysfunction caused by liver tumour and colorectal tumour chemotherapy. Further, the article reveals ex vivo hydrogen application in liver protection. Finally, the article discusses the current and future challenges of hydrogen therapy in liver diseases, aiming to improve knowledge of hydrogen therapy and provide some insights into this burgeoning field.

Potential Therapeutic Applications of Hydrogen in Chronic Inflammatory Diseases: Possible Inhibiting Role on Mitochondrial Stress

Mitochondria are the largest source of reactive oxygen species (ROS) and are intracellular organelles that produce large amounts of the most potent hydroxyl radical (·OH). Molecular hydrogen (H₂) can selectively eliminate ·OH generated inside of the mitochondria. Inflammation is induced by the release of proinflammatory cytokines produced by macrophages and neutrophils. However, an uncontrolled or exaggerated response often occurs, resulting in severe inflammation that can lead to acute or chronic inflammatory diseases. Recent studies have reported that ROS activate NLRP3 inflammasomes, and that this stimulation triggers the production of proinflammatory cytokines. It has been shown in literature that H₂ can be based on the mechanisms that inhibit mitochondrial ROS. However, the ability for H₂ to inhibit NLRP3 inflammasome activation via mitochondrial oxidation is poorly understood. In this review, we hypothesize a possible mechanism by which H₂ inhibits mitochondrial oxidation. Medical applications of H₂ may solve the problem of many chronic inflammation-based diseases, including coronavirus disease 2019 (COVID-19).

Redox Effects of Molecular Hydrogen and Its Therapeutic Efficacy in the Treatment of Neurodegenerative Diseases

Oxidative stress (OS) and neuroinflammatory stress affect many neurological disorders. Despite the clinical significance of oxidative damage in neurological disorders, still, no effective and safe treatment methods for neuro diseases are available. With this, molecular hydrogen (H2) has been recently reported as an antioxidant and anti-inflammatory agent to treat several oxidative stress-related diseases. In animal and human clinical trials, the routes for H2 administration are mainly categorized into three types: H2 gas inhalation, H2 water dissolving, and H2-dissolved saline injection. This review explores some significant progress in research on H2 use in neurodegenerative diseases (NDs), including Alzheimer’s disease, Parkinson’s disease, neonatal disorders of the brain, and other NDs (retinal ischemia and traumatic brain injury). Even though most neurological problems are not currently curable, these studies have shown the therapeutic potential for prevention, treatment, and mitigation of H2 administration. Several possible H2-effectors, including cell signaling molecules and hormones, which prevent OS and inflammation, will also be addressed. However, more clinical and other related studies are required to evaluate the direct H2 target molecule.

Advances in the Protective Mechanism of NO, H2S, and H2 in Myocardial Ischemic Injury

Myocardial ischemic injury is among the top 10 leading causes of death from cardiovascular diseases worldwide. Myocardial ischemia is caused mainly by coronary artery occlusion or obstruction. It usually occurs when the heart is insufficiently perfused, oxygen supply to the myocardium is reduced, and energy metabolism in the myocardium is abnormal. Pathologically, myocardial ischemic injury generates a large number of inflammatory cells, thus inducing a state of oxidative stress. This sharp reduction in the number of normal cells as a result of apoptosis leads to organ and tissue damage, which can be life-threatening. Therefore, effective methods for the treatment of myocardial ischemic injury and clarification of the underlying mechanisms are urgently required. Gaseous signaling molecules, such as NO, H₂S, H₂, and combined gas donors, have gradually become a focus of research. Gaseous signaling molecules have shown anti-apoptotic, anti-oxidative and anti-inflammatory effects as potential therapeutic agents for myocardial ischemic injury in a large number of studies. In this review, we summarize and discuss the mechanism underlying the protective effect of gaseous signaling molecules on myocardial ischemic injury.

Hydrogen: A Novel Option in Human Disease Treatment

H₂ has shown anti-inflammatory and antioxidant ability in many clinical trials, and its application is recommended in the latest Chinese novel coronavirus pneumonia (NCP) treatment guidelines. Clinical experiments have revealed the surprising finding that H₂ gas may protect the lungs and extrapulmonary organs from pathological stimuli in NCP patients. The potential mechanisms underlying the action of H₂ gas are not clear. H₂ gas may regulate the anti-inflammatory and antioxidant activity, mitochondrial energy metabolism, endoplasmic reticulum stress, the immune system, and cell death (apoptosis, autophagy, pyroptosis, ferroptosis, and circadian clock, among others) and has therapeutic potential for many systemic diseases. This paper reviews the basic research and the latest clinical applications of H₂ gas in multiorgan system diseases to establish strategies for the clinical treatment for various diseases.

Chronic molecular hydrogen inhalation mitigates short and long-term memory loss in polymicrobial sepsis

The central nervous system (CNS) is one of the first physiological systems to be affected in sepsis. During the exacerbated systemic inflammatory response at the early stage of sepsis, circulatory inflammatory mediators are able to reach the CNS leading to neuroinflammation and, consequently, long-term impairment in learning and memory formation is observed. The acute treatment with molecular hydrogen (H₂) exerts important antioxidative, antiapoptotic, and anti-inflammatory effects in sepsis, but little is known about the mechanism itself and the efficacy of chronic H₂ inhalation in sepsis treatment. Thus, we tested two hypotheses. We first hypothesized that chronic H₂ inhalation is also an effective therapy to treat memory impairment induced by sepsis. The second hypothesis is that H₂ treatment decreases sepsis-induced neuroinflammation in the hippocampus and prefrontal cortex, important areas related to short and long-term memory processing. Our results indicate that (1) chronic exposure of hydrogen gas is a simple, safe and promising therapeutic strategy to prevent memory loss in patients with sepsis and (2) acute H₂ inhalation decreases neuroinflammation in memory-related areas and increases total nuclear factor E2-related factor 2 (Nrf2), a transcription factorthat regulates a vast group of antioxidant and inflammatory agents expression in these areas of septic animals.

Hydrogen: An Endogenous Regulator of Liver Homeostasis

Basic and clinical studies have shown that hydrogen (H₂), the lightest gas in the air, has significant biological effects of anti-oxidation, anti-inflammation, and anti-apoptosis. The mammalian cells have no abilities to produce H₂ due to lack of the expression of hydrogenase. The endogenous H₂ in human body is mainly produced by anaerobic bacteria, such as Firmicutes and Bacteroides, in gut and other organs through the reversible oxidation reaction of 2 H⁺ + 2 e^- ⇌ H₂. Supplement of exogenous H₂ can improve many kinds of liver injuries, modulate glucose and lipids metabolism in animal models or in human beings. Moreover, hepatic glycogen has strong ability to accumulate H₂, thus, among the organs examined, liver has the highest concentration of H₂ after supplement of exogenous H₂ by various strategies in vivo. The inadequate production of endogenous H₂ play essential roles in brain, heart, and liver disorders, while enhanced endogenous H₂ production may improve hepatitis, hepatic ischemia and reperfusion injury, liver regeneration, and hepatic steatosis. Therefore, the endogenous H₂ may play essential roles in maintaining liver homeostasis.

Molecular Hydrogen Protects Human Melanocytes from Oxidative Stress by Activating Nrf2 Signaling

Oxidative stress is proven to be critical for the initiation and progression of vitiligo. Molecular hydrogen (H₂) possesses potent antioxidant activity and has been shown to protect against various oxidative stress-related diseases. In this study, we first investigated the effects and mechanisms of H₂ in human melanocytes damaged by hydrogen peroxide. We initially found that H₂ reduced intracellular ROS accumulation and malondialdehyde levels in both vitiligo specimens and hydrogen peroxide-treated melanocytes in vitro in a concentration- and time-dependent manner, concomitant with the enhancement of antioxidant enzyme activity. Correspondingly, H₂ reversed hydrogen peroxide-induced apoptosis and dysfunction in both normal and vitiligo melanocytes. H₂ protected mitochondrial morphology and function in melanocytes under stress and promoted the activation of Nrf2 signaling, whereas Nrf2 deficiency abolished the protective effect of H₂ against hydrogen peroxide-induced oxidative damage. Furthermore, H₂ positively modulated β-catenin in hydrogen peroxide-treated melanocytes, and the β-catenin pathway was implicated in H₂-induced Nrf2 activation. Collectively, our results indicate that H₂ could be a promising therapeutic agent for vitiligo treatment via attenuating oxidative damage, and its beneficial effect in human melanocytes might involve Wnt/β-catenin-mediated activation of Nrf2 signaling.

Inhalation of molecular hydrogen prevents ischemia-reperfusion liver damage during major liver resection

Background

Liver resection is a surgical procedure associated with a high risk of hepatic failure that can be fatal. One of the key mechanisms involves ischemia-reperfusion damage. Building on the well-known positive effects of hydrogen at mitigating this damage, the goal of this work was to demonstrate the antioxidant, anti-inflammatory, and anti-apoptotic effects of inhaled hydrogen in domestic pigs during major liver resection.

Methods

The study used a total of 12 domestic pigs, 6 animals underwent resection with inhaled hydrogen during general anesthesia, and 6 animals underwent the same procedure using conventional, unsupplemented, general anesthesia. Intraoperative preparation of the left branch of the hepatic portal vein and the left hepatic artery was performed, and a tourniquet was applied. Warm ischemia was induced for 120 minutes and then followed by liver reperfusion for another 120 minutes. Samples from the ischemic and non-ischemic halves of the liver were then removed for histological and biochemical examinations.

Results

An evaluation of histological changes was based on a numerical expression of damage based on the Suzuki score. Liver samples in the group with inhaled hydrogen showed a statistically significant reduction in histological changes compared to the control group. Biochemical test scores showed no statistically significant difference in hepatic transaminases, alkaline phosphatase (ALP), lactate dehydrogenase (LD), and lactate. However, a surprising result was a statistically significant difference in gamma-glutamyl-transferase (GMT). Marker levels of oxidative damage varied noticeably in plasma samples.

Conclusions

In this experimental study, we showed that inhaled hydrogen during major liver resection unquestionably reduced the level of oxidative stress associated with ischemia-reperfusion damage. We confirmed this phenomenon both histologically and by direct measurement of oxidative stress in the organism.

Myalgic encephalomyelitis/chronic fatigue syndrome: From pathophysiological insights to novel therapeutic opportunities

Myalgic encephalomyelitis (ME) or chronic fatigue syndrome (CFS) is a common and disabling condition with a paucity of effective and evidence-based therapies, reflecting a major unmet need. Cognitive behavioural therapy and graded exercise are of modest benefit for only some ME/CFS patients, and many sufferers report aggravation of symptoms of fatigue with exercise. The presence of a multiplicity of pathophysiological abnormalities in at least the subgroup of people with ME/CFS diagnosed with the current international consensus "Fukuda" criteria, points to numerous potential therapeutic targets. Such abnormalities include extensive data showing that at least a subgroup has a pro-inflammatory state, increased oxidative and nitrosative stress, disruption of gut mucosal barriers and mitochondrial dysfunction together with dysregulated bioenergetics. In this paper, these pathways are summarised, and data regarding promising therapeutic options that target these pathways are highlighted; they include coenzyme Q₁₀, melatonin, curcumin, molecular hydrogen and N-acetylcysteine. These data are promising yet preliminary, suggesting hopeful avenues to address this major unmet burden of illness.

Protective role of heme oxygenase-1 in fatty liver ischemia-reperfusion injury

Ischemia-reperfusion (IR) injury is a kind of injury resulting from the restoration of the blood supply after blood vessel closure during liver transplantation and is the main cause of graft failure. The pathophysiological mechanisms of hepatic IR include a variety of oxidative stress responses. Hepatic IR is characterized by ischemia and hypoxia inducing oxidative stress, immune response and apoptosis. Fat-denatured livers are also used as donors due to the lack of liver donors. Fatty liver is less tolerant to IR than normal liver. Heme oxygenase (HO) is an enzyme that breaks down hemoglobin to bilirubin, ferrous iron and carbon monoxide (CO). Inducible HO subtype HO-1 is an important protective molecule in mammalian cells used to improve acute and chronic liver injury owing to its characteristic anti-inflammatory and anti-apoptotic qualities. HO-1 degrades heme, and its reaction product CO has been shown to reduce hepatic IR injury and increase the survival rate of grafts. As an induced form of HO, HO-1 also exerts a protective effect against liver IR injury and may be useful as a new strategy of ameliorating this kind of damage. This review summarizes the protective effects of HO-1 in liver IR injury, especially in fatty liver.

Molecular hydrogen protects against ischemia-reperfusion injury in a mouse fatty liver model via regulating HO-1 and Sirt1 expression

Fatty liver has lower tolerance against ischemia-reperfusion (I/R) injury in liver operations, including liver transplantation. Seeking to ameliorate liver injury following I/R in fatty liver, we examined the protective effect of hydrogen (H₂) saline on I/R liver injury in a methionine and choline-deficient plus high fat (MCDHF) diet-induced fatty liver mouse model. Saline containing 7 ppm H₂ was administrated during the process of I/R. Livers were obtained and analyzed. Primary hepatocytes and Kupffer cells (KCs) were obtained from fatty liver and subjected to hypoxia/reoxygenation. Apoptosis-related proteins and components of the signaling pathway were analyzed after treatment with hydrogen gas. The MCDHF I/R group showed higher levels of AST and ALT in serum, TUNEL-positive apoptotic cells, F4/80 immunopositive cells, mRNA levels of inflammatory cytokines, constituents of the signaling pathway, pro-apoptotic molecules in liver, and KCs and/or primary hepatocytes, compared to the control group. In contrast, H₂ treatment significantly suppressed the signs of I/R injury in fatty liver. Moreover, the expression of Bcl-2, HO-1, and Sirt1 in liver, KCs, and hepatocytes by hydrogen gas were increased, whereas caspase activation, Bax, and acetylation of p53 were suppressed by hydrogen gas. These results demonstrated that H₂ treatment ameliorated I/R liver injury in a fatty liver model by reducing hepatocyte apoptosis, inhibiting macrophage activation and inflammatory cytokines, and inducing HO-1 and Sirt1 expression. Taken togather, treatment with H₂ saline may have a protective effect and safe therapeutic activity during I/R events, such as in liver transplantation with fatty liver.

Post-reperfusion hydrogen gas treatment ameliorates ischemia reperfusion injury in rat livers from donors after cardiac death: a preliminary study

BACKGROUND AND PURPOSE

We reported previously that hydrogen gas (H₂) reduced hepatic ischemia and reperfusion injury (IRI) after prolonged cold storage (CS) of livers retrieved from heart-beating donors. The present study was designed to assess whether H₂ reduced hepatic IRI during donation of a cardiac death (DCD) graft with subsequent CS.

METHODS

Rat livers were harvested after 30-min cardiac arrest and stored for 4 h in University of Wisconsin solution. The graft was reperfused with oxygenated buffer, with or without H₂ (H₂ or NT groups, respectively), at 37° for 90 min on isolated perfused rat liver apparatus.

RESULTS

In the NT group, liver enzyme leakage, apoptosis, necrosis, energy depletion, redox status, impaired microcirculation, and bile production were indicative of severe IRI, whereas in the H₂ group these impairments were significantly suppressed. The phosphorylation of cytoplasmic MKK4 and JNK were enhanced in the NT group and suppressed in the H₂ group. NFkB-p65 and c-Fos in the nucleus were unexpectedly unchanged by IRI regardless of H₂ treatment, indicating the absence of inflammation in this model.

CONCLUSION

H₂ was observed to ameliorate IRI in the DCD liver by maintaining microcirculation, mitochondrial functions, and redox status, as well as suppressing the cytoplasmic MKK4-JNK-mediated cellular death pathway.

Hydrogen gas inhalation protects against cutaneous ischaemia/reperfusion injury in a mouse model of pressure ulcer

Pressure ulcer formation depends on various factors among which repetitive ischaemia/reperfusion(I/R) injury plays a vital role. Molecular hydrogen (H₂) was reported to have protective effects on I/R injuries of various internal organs. In this study, we investigated the effects of H₂ inhalation on pressure ulcer and the underlying mechanisms. H₂ inhalation significantly reduced wound area, 8‐oxo‐dG level (oxidative DNA damage) and cell apoptosis rates in skin lesions. H₂ remarkably decreased ROS accumulation and enhanced antioxidant enzymes activities by up‐regulating expression of Nrf2 and its downstream components in wound tissue and/or H₂O₂‐treated endothelia. Meanwhile, H₂ inhibited the overexpression of MCP‐1, E‐selectin, P‐selectin and ICAM‐1 in oxidant‐induced endothelia and reduced inflammatory cells infiltration and proinflammatory cytokines (TNF‐α, IL‐1, IL‐6 and IL‐8) production in the wound. Furthermore, H₂ promoted the expression of pro‐healing factors (IL‐22, TGF‐β, VEGF and IGF1) and inhibited the production of MMP9 in wound tissue in parallel with acceleration of cutaneous collagen synthesis. Taken together, these data indicated that H₂ inhalation suppressed the formation of pressure ulcer in a mouse model. Molecular hydrogen has potentials as a novel and alternative therapy for severe pressure ulcer. The therapeutic effects of molecular hydrogen might be related to its antioxidant, anti‐inflammatory, pro‐healing actions.

Hydrogen-Rich Water and Lactulose Protect Against Growth Suppression and Oxidative Stress in Female Piglets Fed Fusarium Toxins Contaminated Diets

The objective of the current experiment was to evaluate whether hydrogen-rich water (HRW) or lactulose (LAC) could protect against the adverse effects of Fusarium mycotoxins-contaminated diet on the growth performance and antioxidant status in weaning piglets. A total of 24 individually housed female piglets were randomly assigned to receive four treatments for 25 days (six pigs/treatment): uncontaminated basal diet (negative control), mycotoxin-contaminated (MC) diet, MC diet + HRW (MC + HRW) and MC diet + LAC (MC + LAC). The plasma hydrogen levels before and after 2 h hydrogen-free water/HRW administration were detected at day 21, and the liver hydrogen levels were detected at the end of the experiment. Serum hormones related to appetite regulation, and serum and liver oxidant and antioxidant status were also measured at the end of the experiment. Results showed that both HRW and LAC treatments significantly attenuated the reduction of average daily gain (ADG) and average daily feed intake (ADFI) caused by Fusarium mycotoxins. LAC administration increased the hydrogen concentrations in plasma and liver. HRW treated group had higher plasma hydrogen levels than the MC group. Compared with the NC group, the MC group had significantly increased serum peptide YY (PYY) and cholecystokinin (CCK) levels. Interestingly, both HRW and LAC administrations had a lower reduced serum PYY and CKK levels. Most importantly, oral administration of HRW and LAC attenuated the Fusarium mycotoxins-induced oxidative stress. In conclusion, oral administration of hydrogen-rich water or lactulose could both protect against the growth reduction and oxidative damage caused by Fusarium mycotoxins.

Hydrogen protects against liver injury during CO2 pneumoperitoneum in rats

The aim of the current study was to identify the protective effect of hydrogen gas against liver injury during CO₂ pneumoperitoneum. Rats were randomly divided into three groups: control group (C group), pneumoperitoneum group (P15 group) and hydrogen group (H₂ group). Rats in the C group were subjected to anesthesia for 90 min. Rats in the P15 group received an abdominal insufflation of CO₂ for 90 min at an intra-abdominal pressure of 15 mmHg. Rats in the H₂ group received a hypodermic injection of hydrogen gas (0.2 mL/kg) and after 10 min they received an abdominal insufflation of CO₂ for 90 min at an intra-abdominal pressure of 15 mmHg. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured to evaluate liver function. Malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) content were measured to evaluate oxidative stress. Nuclear factor E2-related factor 2 (Nrf2) and Nrf2 downstream target genes, apoptosis-related genes and inflammatory cytokine mRNA and protein expression were detected. Liver injury was detected under the microscope. Our results revealed that liver function, antioxidants content, inflammation and liver injury were improved after hydrogen preconditioning in H₂ group compared with P15 group. Overall, our results revealed that subcutaneous hydrogen injection could exert a protective effect against liver injury during CO₂ pneumoperitoneum through reducing oxidative stress, cell apoptosis and inflammatory cytokines release.

Molecular hydrogen: a preventive and therapeutic medical gas for various diseases

Since the 2007 discovery that molecular hydrogen (H2) has selective antioxidant properties, multiple studies have shown that H2 has beneficial effects in diverse animal models and human disease. This review discusses H2 biological effects and potential mechanisms of action in various diseases, including metabolic syndrome, organ injury, and cancer; describes effective H2 delivery approaches; and summarizes recent progress toward H2 applications in human medicine. We also discuss remaining questions in H2 therapy, and conclude with an appeal for a greater role for H2 in the prevention and treatment of human ailments that are currently major global health burdens. This review makes a case for supporting hydrogen medicine in human disease prevention and therapy.

Protective effect of hydrogen-rich water on liver function of colorectal cancer patients treated with mFOLFOX6 chemotherapy

The present study was conducted to investigate the protective effect of hydrogen-rich water on the liver function of colorectal cancer (CRC) patients treated with mFOLFOX6 chemotherapy. A controlled, randomized, single-blind clinical trial was designed. A total of 152 patients with CRC were recruited by the Department of Oncology of Taishan Hospital (Taian, China) between June 2010 and February 2016, among whom 146 met the inclusion criteria. Subsequently, 144 patients were randomized into the treatment (n=80) and placebo (n=64) groups. At the end of the study, 76 patients in the hydrogen treatment group and 60 patients in the placebo group were included in the final analysis. The changes in liver function after the chemotherapy, such as altered levels of alanine aminotransferase (ALT), aspartate transaminase (AST), alkaline phosphatase, indirect bilirubin (IBIL) and direct bilirubin, were observed. The damaging effects of the mFOLFOX6 chemotherapy on liver function were mainly represented by increased ALT, AST and IBIL levels. The hydrogen-rich water group exhibited no significant differences in liver function before and after treatment, whereas the placebo group exhibited significantly elevated levels of ALT, AST and IBIL. Thus, hydrogen-rich water appeared to alleviate the mFOLFOX6-related liver injury.

Image-Guided Hydrogen Gas Delivery for Protection from Myocardial Ischemia-Reperfusion Injury via Microbubbles

Cardiomyocyte death induced by ischemia-reperfusion is a major cause of morbidity and mortality worldwide. Hydrogen (H₂), as an antioxidant, has been shown to have great potential in preventive and therapeutic applications against lethal injury that occurs from ischemia-reperfusion. However, H₂ is sparingly soluble in water, resulting in its poor bioavailability in blood and damaged tissues. Here, we have developed an ultrasound-visible H₂ delivery system by loading H₂ inside microbubbles (H₂-MBs) to prevent myocardial ischemia-reperfusion injury. Using this system, the concentration of H₂ in unit volume can be greatly improved under normal temperature and pressure conditions. H₂-MBs can be visually tracked with ultrasound imaging systems and can effectively release their therapeutic gas. In vivo systemic delivery of H₂-MBs in myocardial ischemic rats at the start of reperfusion resulted in a significant reduction of infarct size and pathological remodeling. Further analysis showed that this approach markedly inhibited cardiomyocyte apoptosis and reduced myocardial inflammation and oxidant damage in myocardial ischemia-reperfusion rats. These results indicate that H₂-MBs are a promising visual delivery system for H₂-based therapeutic applications.

Saturated hydrogen saline ameliorates lipopolysaccharide-induced acute lung injury by reducing excessive autophagy

The pathogenesis of acute lung injury (ALI) induced by lipopolysaccharide (LPS) involves excessive pulmonary inflammation and oxidative stress. In turn, autophagy is associated with inflammatory diseases and organ dysfunction, and studies have demonstrated that LPS treatment may trigger autophagy. Thus, excessive autophagy may stimulate the strong inflammatory response observed in the development of LPS-induced ALI. Saturated hydrogen saline may alleviate LPS-induced ALI by inhibiting autophagy, however its underlying mechanisms of action remain unknown. It has been suggested that saturated hydrogen saline may downregulate expression of nuclear factor (NF)-κB, leading to a decrease in Beclin-1 transcription and inhibition of autophagy. Inhibition of autophagy also occurs via the phosphorylation of Unc-51-like autophagy activating kinase 1 and autophagy-related protein-13 by mechanistic target of rapamycin, which in turn may be upregulated by saturated hydrogen saline. In addition, signaling pathways involving heme oxygenase-1 and p38 mitogen-activated protein kinase are associated with the alleviative effects of saturated hydrogen saline on LPS-induced autophagy. The present review focuses on potential molecular mechanisms regarding the effects of saturated hydrogen saline in the reduction of autophagy during LPS-induced ALI.

Preventive and therapeutic application of molecular hydrogen in situations with excessive production of free radicals

Excessive production of oxygen free radicals has been regarded as a causative common denominator of many pathological processes in the animal kingdom. Hydroxyl and nitrosyl radicals represent the major cause of the destruction of biomolecules either by a direct reaction or by triggering a chain reaction of free radicals. Scavenging of free radicals may act preventively or therapeutically. A number of substances that preferentially react with free radicals can serve as scavengers, thus increasing the internal capacity/activity of endogenous antioxidants and protecting cells and tissues against oxidative damage. Molecular hydrogen (H(2)) reacts with strong oxidants, such as hydroxyl and nitrosyl radicals, in the cells, that enables utilization of its potential for preventive and therapeutic applications. H(2) rapidly diffuses into tissues and cells without affecting metabolic redox reactions and signaling reactive species. H(2) reduces oxidative stress also by regulating gene expression, and functions as an anti-inflammatory and anti-apoptotic agent. There is a growing body of evidence based on the results of animal experiments and clinical observations that H(2) may represent an effective antioxidant for the prevention of oxidative stress-related diseases. Application of molecular hydrogen in situations with excessive production of free radicals, in particular, hydroxyl and nitrosyl radicals is relatively simple and effective, therefore, it deserves special attention.

Hydrogen, a potential safeguard for graft-versus-host disease and graft ischemia-reperfusion injury?

Post-transplant complications such as graft-versus-host disease and graft ischemia-reperfusion injury are crucial challenges in transplantation. Hydrogen can act as a potential antioxidant, playing a preventive role against post-transplant complications in animal models of multiple organ transplantation. Herein, the authors review the current literature regarding the effects of hydrogen on graft ischemia-reperfusion injury and graft-versus-host disease. Existing data on the effects of hydrogen on ischemia-reperfusion injury related to organ transplantation are specifically reviewed and coupled with further suggestions for future work. The reviewed studies showed that hydrogen (inhaled or dissolved in saline) improved the outcomes of organ transplantation by decreasing oxidative stress and inflammation at both the transplanted organ and the systemic levels. In conclusion, a substantial body of experimental evidence suggests that hydrogen can significantly alleviate transplantation-related ischemia-reperfusion injury and have a therapeutic effect on graft-versus-host disease, mainly via inhibition of inflammatory cytokine secretion and reduction of oxidative stress through several underlying mechanisms. Further animal experiments and preliminary human clinical trials will lay the foundation for hydrogen use as a drug in the clinic.

The potential utilizations of hydrogen as a promising therapeutic strategy against ocular diseases

Hydrogen, one of the most well-known natural molecules, has been used in numerous medical applications owing to its ability to selectively neutralize cytotoxic reactive oxygen species and ameliorate hazardous inflammations. Hydrogen can exert protective effects on various reactive oxygen species-related diseases, including the transplantation-induced intestinal graft injury, chronic inflammation, ischemia–reperfusion injuries, and so on. Especially in the eye, hydrogen has been used to counteract multiple ocular pathologies in the ophthalmological models. Herein, the ophthalmological utilizations of hydrogen are systematically reviewed and the underlying mechanisms of hydrogen-induced beneficial effects are discussed. It is our hope that the protective effects of hydrogen, as evidenced by these pioneering studies, would enrich our pharmacological knowledge about this natural element and cast light into the discovery of a novel therapeutic strategy against ocular diseases.

Hydrogen Gas Ameliorates Hepatic Reperfusion Injury After Prolonged Cold Preservation in Isolated Perfused Rat Liver

Hydrogen gas reduces ischemia and reperfusion injury (IRI) in the liver and other organs. However, the precise mechanism remains elusive. We investigated whether hydrogen gas ameliorated hepatic I/R injury after cold preservation. Rat liver was subjected to 48-h cold storage in University of Wisconsin solution. The graft was reperfused with oxygenated buffer with or without hydrogen at 37° for 90 min on an isolated perfusion apparatus, comprising the H₂ (+) and H₂ (-) groups, respectively. In the control group (CT), grafts were reperfused immediately without preservation. Graft function, injury, and circulatory status were assessed throughout the perfusion. Tissue samples at the end of perfusion were collected to determine histopathology, oxidative stress, and apoptosis. In the H₂ (-) group, IRI was indicated by a higher aspartate aminotransferase (AST), alanine aminotransferase (ALT) leakage, portal resistance, 8-hydroxy-2-deoxyguanosine-positive cell rate, apoptotic index, and endothelial endothelin-1 expression, together with reduced bile production, oxygen consumption, and GSH/GSSG ratio (vs. CT). In the H₂ (+) group, these harmful changes were significantly suppressed [vs. H₂ (-)]. Hydrogen gas reduced hepatic reperfusion injury after prolonged cold preservation via the maintenance of portal flow, by protecting mitochondrial function during the early phase of reperfusion, and via the suppression of oxidative stress and inflammatory cascades thereafter.

Hydrogen therapy: from mechanism to cerebral diseases

The medicinal value of hydrogen (H₂) was ignored prior to research illustrating that inhalation of 2% H₂ can significantly decrease the damage of cerebral ischemia/reperfusion caused by oxidative stress via selective elimination of hydroxyl freebase (OH) and peroxynitrite anion (ONOOˉ). Subsequently, there have been numerous experiments on H₂. Most research and trials involving the mechanisms underlying H₂ therapy show the effects of antioxygenation, anti-inflammation, and anti-apoptosis. Among quantities of diseases related with H₂ therapy, the brain disease is a hotspot as brain tissue and cell damage are easier to be induced by oxidative stress and other stimulations. In this review, emphasis is on stroke, traumatic brain injuries, and degenerative diseases, such as Alzheimer's disease and Parkinson's disease. Taking into account the blood-brain barrier, penetrability, possible side effects, and the molecular properties of H₂ within a single comprehensive review should contribute to advancing both clinical and non-clinical research and therapies. A systematic introduction of H₂ therapy with regards to mechanisms and cerebral diseases both in animal and human subjects can make it easier to comprehend H₂ therapy and therefore provide the basis for further clinical strategy.

Hydrogen-rich saline protects against mitochondrial dysfunction and apoptosis in mice with obstructive jaundice

Previous studies have demonstrated that hydrogen-rich saline (HS) protects against bile duct ligation (BDL)-induced liver injury by suppressing oxidative stress and inflammation. Mitochondria, which are targets of excessive reactive oxygen species and central mediators of apoptosis, have a pivotal role in hepatic injury during obstructive jaundice (OJ); however, the implications of HS in the hepatic mitochondria of BDL mice remain unknown. The present study investigated the hypothesis that HS could reduce OJ‑induced liver injury through the protection of mitochondrial structure and function, as well as inhibition of the mitochondrial apoptotic pathway. Male C57BL/6 mice were randomly divided into three experimental groups: Sham operation group, BDL injury with normal saline (NS) treatment group, and BDL‑injury with HS treatment group. Mitochondrial damage and apoptotic parameters were determined 3 days post‑BDL injury and treatment. The results demonstrated that mitochondria isolated from the livers of NS-treated BDL mice exhibited increased mitochondrial swelling, cytochrome c release, and oxidative damage. In addition, liver samples from NS‑treated BDL mice exhibited significant increases in B‑cell lymphoma 2 (Bcl‑2)‑associated X protein expression, caspase activities, and hepatocyte apoptosis compared with livers from sham‑operated controls. Notably, treatment with HS reduced the levels of these markers and alleviated morphological defects in the mitochondria following injury. In addition, HS markedly increased the antioxidant potential of mitochondria, as evidenced by elevated adenosine triphosphate levels, mitochondrial respiratory function, and increased levels of active Bcl‑2. In conclusion, HS attenuates mitochondrial oxidative stress and dysfunction, and inhibits mitochondrial-mediated apoptosis in the livers of BDL mice.

Beneficial biological effects and the underlying mechanisms of molecular hydrogen - comprehensive review of 321 original articles

Therapeutic effects of molecular hydrogen for a wide range of disease models and human diseases have been investigated since 2007. A total of 321 original articles have been published from 2007 to June 2015. Most studies have been conducted in Japan, China, and the USA. About three-quarters of the articles show the effects in mice and rats. The number of clinical trials is increasing every year. In most diseases, the effect of hydrogen has been reported with hydrogen water or hydrogen gas, which was followed by confirmation of the effect with hydrogen-rich saline. Hydrogen water is mostly given ad libitum. Hydrogen gas of less than 4 % is given by inhalation. The effects have been reported in essentially all organs covering 31 disease categories that can be subdivided into 166 disease models, human diseases, treatment-associated pathologies, and pathophysiological conditions of plants with a predominance of oxidative stress-mediated diseases and inflammatory diseases. Specific extinctions of hydroxyl radical and peroxynitrite were initially presented, but the radical-scavenging effect of hydrogen cannot be held solely accountable for its drastic effects. We and others have shown that the effects can be mediated by modulating activities and expressions of various molecules such as Lyn, ERK, p38, JNK, ASK1, Akt, GTP-Rac1, iNOS, Nox1, NF-κB p65, IκBα, STAT3, NFATc1, c-Fos, and ghrelin. Master regulator(s) that drive these modifications, however, remain to be elucidated and are currently being extensively investigated.

Hydrogen-rich saline may be an effective and specific novel treatment for osteoradionecrosis of the jaw

Hydrogen, a therapeutic medical gas, can exert antioxidant activity via selectively reducing cytotoxic reactive oxygen species such as hydroxyl radicals. Hydrogen-rich saline is an alternative form of molecular hydrogen that has been widely used in many studies, including metabolic syndrome, cerebral, hepatic, myocardial ischemia/reperfusion, and liver injuries with obstructive jaundice, with beneficial results. Osteoradionecrosis of the jaw is a serious complication following radiotherapy for head and neck cancers. It has long been known that most radiation-induced symptoms are caused by free radicals generated by radiolysis of H₂O, and the hydroxyl radical is the most reactive of these. Reducing the hydroxyl radical can distinctly improve the protection of cells from radiation damage. We hypothesized that hydrogen-rich saline might be an effective and specific method of managing and preventing osteoradionecrosis of the jaw.

Hydrogen resuscitation, a new cytoprotective approach

1. Hydrogen is a colourless, odourless, tasteless and flammable gas. Hydrogen is considered a physiologically inert gas and is often used in deep sea diving medicine. In mammals, endogenous hydrogen is produced as a result of the fermentation of non-digestible carbohydrates by intestinal bacteria and it is absorbed into the systemic circulation. 2. Recent evidence indicates that hydrogen is a potent anti-oxidative, anti-apoptotic and anti-inflammatory agent and so may have potential medical application. The present review evaluates the concept of 'hydrogen resuscitation', based on knowledge that hydrogen treatment effectively protects cells, tissues and organs against oxidative injury and helps them recover from dysfunction. 3. Hydrogen therapy can be delivered by inhalation, the administration of hydrogen-enriched fluid or by approaches that affect endogenous hydrogen production. 4. Studies have shown that hydrogen resuscitation has cytoprotective effects in different cell types and disease models, including ischaemia-reperfusion injury, inflammation, toxicity, trauma and metabolic disease. The underlying mechanism may be the selective elimination of hydroxyl radicals, although other mechanisms may also be involved (e.g. hydrogen functioning as a gaseous signalling molecule). 5. Hydrogen resuscitation may have several potential advantages over current pharmacological therapies for oxidative injuries. However, more work is needed to identify the precise mechanism underlying the actions of hydrogen and to validate its therapeutic potential in the clinical setting.

Saturated hydrogen saline attenuates endotoxin-induced lung dysfunction

BACKGROUND

Acute lung injury induced by lipopolysaccharides (LPSs) is caused by pulmonary inflammation and pulmonary vascular permeability. Activation of p38 mitogen-activated protein kinase causes inflammation, and proinflammatory cytokines and oxidative stress induce autophagy, a catabolic mechanism responsible for protein degradation and recycling of damaged proteins and cytoplasmic organelles. If not controlled, excessive autophagy responses can result in cell death.

MATERIALS AND METHODS

In this study, we pretreated rats with saturated hydrogen saline, and examined the molecular mechanism by which saturated hydrogen saline attenuates LPS-induced acute lung dysfunction. Sixty-four male Sprague-Dawley rats were randomly assigned to one of three groups--a control group, an LPS group, or an LPS plus saturated hydrogen saline (LPS + H2) group.

RESULTS

Treatment with saturated hydrogen saline prolonged the median survival time of rats and reduced lung dysfunction induced by LPS. Moreover, saturated hydrogen saline significantly attenuated LPS-mediated induction of serum tumor necrosis factor α, interleukin 6, myeloperoxidase, and malondialdehyde (P < 0.05).

CONCLUSIONS

Autophagosomes were found in the cytoplasm of type II alveolar epithelial cells of LPS-treated rats, and light chain 3 protein (LC3)I/II was increased by LPS treatment. In contrast, saturated hydrogen saline decreased the number of autophagosomes and LC3I/II expression. Saturated hydrogen saline also attenuated the LPS-mediated increase in apoptosis and p38 expression. Taken together, saturated hydrogen saline may attenuate LPS-induced acute lung dysfunction in rats by reducing inflammation, autophagy, and apoptosis involving the p38 mitogen-activated protein kinase signaling pathway.

Administration of hydrogen-rich saline in mice with allogeneic hematopoietic stem-cell transplantation

BACKGROUND

Hydrogen, as a novel antioxidant, has been shown to selectively reduce the level of hydroxyl radicals and alleviate acute oxidative stress in many animal experiments. Hydrogen-rich saline provides a high concentration of hydrogen that can be easily and safely applied. Allogeneic hematopoietic stem-cell transplantation (HSCT) has been the most curative therapy for hematological malignancies. However, acute graft-versus-host disease (aGVHD) is the main cause of death in post-transplantation patients. In this study, we examined whether hydrogen-rich saline would show favorable effects on acute GVHD in mice.

MATERIAL AND METHODS

After lethal irradiation, BALB/c mice received bone marrow transplantation from C57BL/6 mice. Hydrogen-rich saline (5 ml/kg) was given to recipient mice in the hydrogen group once a day by intraperitoneal injection, and saline (5 ml/kg) was given to recipient mice in the saline group. Survival rates were monitored, clinical and pathological scores of aGVHD were determined after bone marrow transplantation (BMT), and the serum cytokine levels were examined on the 7th day after BMT.

RESULTS

This study proves that hydrogen-rich saline increased the survival rate, reduced clinical and histopathological scores of aGVHD, promoted the recovery of white blood cells, reduced the serum cytokine levels, and reversed tissue damage after transplantation in mice.

CONCLUSIONS

Hydrogen has potential as an effective and safe therapeutic agent in aGVHD.

Hydrogen-rich saline ameliorates lung injury associated with cecal ligation and puncture-induced sepsis in rats

AIMS

Although hydrogen has been proved to be a novel therapeutic medical gas in several lung injury animal models, to our knowledge, it has not been tested yet in acute lung injury (ALI) induced by cecal ligation and puncture (CLP). This study was to investigate the hypothesis that hydrogen could ameliorate CLP-induced lung injury in rats.

METHODS AND RESULTS

Our experiments exhibited that gas exchange dysfunction and lung tissue inflammation were observed in animals exposed to CLP. Hydrogen-rich saline treatment significantly attenuated lung injury as indicated by significantly improved gas exchange and histological changes in the lung and significantly reduced lung water content (LWC) and neutrophil infiltration 8h after CLP. Lipid peroxidation and DNA oxidation in the lung tissue were significantly reduced along with a decreased nitrotyrosine content and maintained superoxide dismutase activity in the presence of hydrogen, demonstrating antioxidant role of hydrogen in CLP-induced ALI. Importantly, hydrogen-rich saline treatment significantly inhibited the activation of p-p38 and NF-κB while suppressing the production of several proinflammatory mediators.

CONCLUSIONS

This observation indicated that hydrogen-rich saline peritoneal injection improves histological and functional assessment in rat model of CLP-induced ALI. The therapeutic effects of hydrogen-rich saline may be related to antioxidant and anti-inflammatory actions.

Lactulose accelerates liver regeneration in rats by inducing hydrogen

BACKGROUND

Oxidative stress and inflammation are implicated in the process of liver regeneration. Lactulose orally administered can be bacterially fermented and induces dramatic amounts of endogenous hydrogen. Hydrogen has been confirmed to have antioxidant and anti-inflammatory properties. This study investigated the potential influence of lactulose administration on liver regeneration.

MATERIALS AND METHODS

Antibiotics were used to suppress bacterial fermentation of lactulose, and hydrogen-rich saline was used as a supplementary measure of exogenous hydrogen. The liver regeneration model was produced in Sprague-Dawley rats through 70% partial hepatectomy.

RESULTS

Compared with non-lactulose-treated group, lactulose administration remarkably increased the weights of remnant liver and inhibited increases in serum levels of transaminases more notably. In the lactulose-treated group, increases of markers for regeneration, such as proliferating cell nuclear antigen and cyclin D1, were highly elevated. Biochemically, lactulose administration increased liver superoxide dismutase activity and decreased malondialdehyde content. In the lactulose-treated group, excessive increases in inflammatory cytokines, such as interleukin-6 and tumor necrosis factor-α, were inhibited significantly. Increased heme oxygenase-1 and superoxide dismutase 2 expression were also observed after lactulose treatment. The antibiotics suppressed the regeneration-promoting effect of lactulose by reducing hydrogen production, whereas supplementing hydrogen by hydrogen-rich saline would get a similar regeneration-promoting effect as lactulose administration.

CONCLUSIONS

Lactulose administration accelerates posthepatectomized liver regeneration in rats by inducing hydrogen, which may result from attenuation of the oxidative stress response and excessive inflammatory response.

Hydrogen supplementation of preservation solution improves viability of osteochondral grafts

Allogenic osteochondral tissue (OCT) is used for the treatment of large cartilage defects. Typically, OCTs collected during the disease-screening period are preserved at 4°C; however, the gradual reduction in cell viability during cold preservation adversely affects transplantation outcomes. Therefore, improved storage methods that maintain the cell viability of OCTs are needed to increase the availability of high-quality OCTs and improve treatment outcomes. Here, we evaluated whether long-term hydrogen delivery to preservation solution improved the viability of rat OCTs during cold preservation. Hydrogen-supplemented Dulbecco's Modified Eagles Medium (DMEM) and University of Wisconsin (UW) solution both significantly improved the cell viability of OCTs during preservation at 4°C for 21 days compared to nonsupplemented media. However, the long-term cold preservation of OCTs in DMEM containing hydrogen was associated with the most optimal maintenance of chondrocytes with respect to viability and morphology. Our findings demonstrate that OCTs preserved in DMEM supplemented with hydrogen are a promising material for the repair of large cartilage defects in the clinical setting.

A review of experimental studies of hydrogen as a new therapeutic agent in emergency and critical care medicine

Hydrogen is the most abundant chemical element in the Universe, but is seldom regarded as a therapeutic agent. Recent evidence has shown that hydrogen is a potent antioxidative, antiapoptotic and anti-inflammatory agent and so may have potential medical applications in cells, tissues and organs. There are several methods to administer hydrogen, such as inhalation of hydrogen gas, aerosol inhalation of a hydrogen-rich solution, drinking hydrogen dissolved in water, injecting hydrogen-rich saline (HRS) and taking a hydrogen bath. Drinking hydrogen solution (saline/pure water/other solutions saturated with hydrogen) may be more practical in daily life and more suitable for daily consumption. This review summarizes the findings of recent studies on the use of hydrogen in emergency and critical care medicine using different disease models.

Hydrogen gas protects against serum and glucose deprivation‑induced myocardial injury in H9c2 cells through activation of the NF‑E2‑related factor 2/heme oxygenase 1 signaling pathway

Ischemia or hypoxia‑induced myocardial injury is closely associated with oxidative stress. Scavenging free radicals and/or enhancing endogenous antioxidative defense systems may be beneficial for the impediment of myocardial ischemic injury. Hydrogen (H2) gas, as a water‑ and lipid‑soluble small molecule, is not only able to selectively eliminate hydroxyl (·OH) free radicals, but also to enhance endogenous antioxidative defense systems in rat lungs and arabidopsis plants. However, thus far, it has remained elusive whether H2 gas protects cardiomyocytes through enhancement of endogenous antioxidative defense systems. In the present study, the cardioprotective effect of H2 gas against ischemic or hypoxic injury was investigated, along with the underlying molecular mechanisms. H9c2 cardiomyoblasts (H9c2 cells) were treated in vitro with a chemical hypoxia inducer, cobalt chloride (CoCl2), to imitate hypoxia, or by serum and glucose deprivation (SGD) to imitate ischemia. Cell viability and intracellular ·OH free radicals were assessed. The role of an endogenous antioxidative defense system, the NF‑E2‑related factor 2 (Nrf2)/heme oxygenase 1 (HO‑1) signaling pathway, was evaluated. The findings revealed that treatment with CoCl2 or SGD markedly reduced cell viability in H9c2 cells. H2 gas‑rich medium protected against cell injury induced by SGD, but not that induced by CoCl2. When the cells were exposed to SGD, levels of intracellular ·OH free radicals were markedly increased; this was mitigated by H2 gas‑rich medium. Exposure of the cells to SGD also resulted in significant increases in HO‑1 expression and nuclear Nrf2 levels, and the HO‑1 inhibitor ZnPP IX and the Nrf2 inhibitor brusatol aggravated SGD‑induced cellular injury. H2 gas‑rich medium enhanced SGD‑induced upregulation of HO‑1 and Nrf2, and the HO‑1 or Nrf2 inhibition partially suppressed H2 gas‑induced cardioprotection. Furthermore, following genetic silencing of Nrf2 by RNA interference, the effects of H2 gas on the induction of HO‑1 and cardioprotection were markedly reduced. In conclusion, H2 gas protected cardiomyocytes from ischemia‑induced myocardial injury through elimination of ·OH free radicals and also through activation of the Nrf2/HO‑1 signaling pathway.

The hepatoprotective effect and chemical constituents of total iridoids and xanthones extracted from Swertia mussotii Franch

ETHNOPHARMACOLOGICAL RELEVANCE

Total iridoids and xanthones (TIXS) were extracted from Swertia mussotii Franch, one of the most important eight Tibetan medicines in China, which was recorded in the book of Jingzhu Bencao and used for clinical treatment of cholestatic hepatitis for many years. Our aim was to study the hepatoprotective effect and chemical constituents of the TIXS.

MATERIALS AND METHODS

Crude extracts were prepared using 90% ethanol, and individual fractions were collected following HPD-300 macroporous resin column chromatography. HPLC/MS was applied to qualitatively and quantitatively analyze the TIXS. Then, the alpha-naphthylisot hiocyanate-induced liver damage model was used to assess the hepatoprotective effect of the TIXS.

RESULTS

A total of 12 compounds were identified by the fingerprint chromatography of the TIXS, and swertiamarin and swertianolin were shown to be its two main components. Oral administration of the TIXS at a dose of 35, 70 or 140 mg kg(-1), swertiamarin at a dose of 20 mg kg(-1) or swertianolin at a dose of 20 mg kg(-1), for 7 days in mice significantly reduced the alpha-naphthylisot hiocyanate-induced levels of alanine aminotransferase, aspartate aminotransferase and the total and direct bilirubins, and increased the bile flow (P<0.01).

CONCLUSION

These findings suggest that the TIXS exhibits significant hepatoprotective effect in the liver damage model induced by alpha-naphthylisot hiocyanate. Its active constituents include swertiamarin and swertianolin.

Neuroprotective effect of hydrogen-rich saline against neurologic damage and apoptosis in early brain injury following subarachnoid hemorrhage: possible role of the Akt/GSK3β signaling pathway

Backgrounds

Early brain injury (EBI) plays a key role in the pathogenesis of subarachnoid hemorrhage (SAH). Neuronal apoptosis is involved in the pathological process of EBI. Hydrogen can inhibit neuronal apoptosis and attenuate EBI following SAH. However, the molecular mechanism underlying hydrogen-mediated anti-apoptotic effects in SAH has not been elucidated. In the present study, we aimed to evaluate whether hydrogen alleviates EBI after SAH, specifically neuronal apoptosis, partially via the Akt/GSK3β signaling pathway.

Methods

Sprague-Dawley rats (n = 85) were randomly divided into the following groups: sham group (n = 17), SAH group (n = 17), SAH + saline group (n = 17), SAH + hydrogen-rich saline (HS) group (n = 17) and SAH + HS + Ly294002 (n = 17) group. HS or an equal volume of physiological saline was administered immediately after surgery and repeated 8 hours later. The PI3K inhibitor, Ly294002, was applied to manipulate the proposed pathway. Neurological score and SAH grade were assessed at 24 hours after SAH. Western blot was used for the quantification of Akt, pAkt, GSK3β, pGSK3β, Bcl-2, Bax and cleaved caspase-3 proteins. Neuronal apoptosis was identified by double staining of terminal deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining and NeuN, and quantified by apoptosis index. Immunohistochemistry and immunofluorescent double-labeling staining was performed to clarify the relationships between neuronal apoptosis and pAkt or pGSK3β.

Results

HS significantly reduced neuronal apoptosis and improved neurological function at 24 hours after SAH. The levels of pAkt and pGSK3β, mainly expressed in neurons, were markedly up-regulated. Additionally, Bcl-2 was significantly increased while Bax and cleaved caspase-3 was decreased by HS treatment. Double staining of pAkt and TUNEL showed few colocalization of pAkt-positive cells and TUNEL-positive cells. The inhibitor of PI3K, Ly294002, suppressed the beneficial effects of HS.

Conclusions

HS could attenuate neuronal apoptosis in EBI and improve the neurofunctional outcome after SAH, partially via the Akt/GSK3β pathway.

Saturated hydrogen saline attenuates endotoxin-induced acute liver dysfunction in rats

To determine the effect of saturated hydrogen saline on lipopolysaccharide (LPS)-induced acute liver dysfunction, rats were divided into control, LPS, and LPS plus saturated hydrogen saline (LPS+H(2)) groups. Treatment with saturated hydrogen saline prolonged the median survival time and reduced liver dysfunction. Moreover, saturated hydrogen saline significantly reduced pathological alterations in liver tissues, the number of ballooned hepatocytes, serum tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 levels, and myeloperoxidase (MPO) and malondialdehyde (MDA) levels in liver tissues (P<0.05). Cell apoptosis was detected in liver tissues after LPS treatment, and attenuated by saturated hydrogen saline treatment. Saturated hydrogen saline also decreased phosphorylated extracellular signal-regulated kinase (p-ERK), phosphorylated Jun kinase (p-JNK), nuclear factor-kappa B (NF-kappaB), and second mitochondria-derived activator of caspase (Smac) levels, and increased p38 activation (P<0.05). Thus, saturated hydrogen saline may attenuate LPS-induced acute liver dysfunction in rats, possibly by reducing inflammation and cell apoptosis. Mitogen-activated protein kinase (MAPK), NF-kappaB, and Smac may contribute to saturated hydrogen saline-mediated liver protection.

Molecular hydrogen suppresses reactive astrogliosis related to oxidative injury during spinal cord injury in rats

AIMS

Spinal cord injury (SCI) can induce excessive astrocyte activation. Hydrogen has been deemed as a novel antioxidant. We investigated whether molecular hydrogen could act as an antiastrogliosis agent during SCI and oxidative injury in experimental rats and cultured astrocytes.

METHODS

Hydrogen-rich saline (HS, 8 mL/kg, i.p.) was injected every 12 h after SCI in rats. The expression of STAT3, p-STAT3, and glial fibrillary acidic protein (GFAP); the release of IL-1β, IL-6, and TNF-α; and astrogliosis, along with the BBB score, were evaluated. Culturing astrocytes with hydrogen-rich medium, the intracellular reactive oxygen species (ROS), astrogliosis, and the release of proinflammatory cytokines were assessed after H2O2-induced injury.

RESULTS

In the HS group, the expression of STAT3, p-STAT3, and GFAP and the proinflammatory cytokines were decreased in local spinal cord on postoperation day (POD) 3; on PODs 7 and 14, reactive astrogliosis was suppressed, and the locomotor function was also improved. Furthermore, hydrogen-rich medium attenuated the intracellular production of ROS (especially HO•), astrogliosis, and the secretion of proinflammatory cytokines in astrocytes 12 h after H2O2-induced injury.

CONCLUSIONS

Molecular hydrogen could suppress reactive astrogliosis after contusive SCI and reduce the release of proinflammatory cytokines produced by active astrocytes related to oxidative injury. Thus, molecular hydrogen is potential to be a neuroprotective agent.

Dose-dependent inhibition of gastric injury by hydrogen in alkaline electrolyzed drinking water

Background

Hydrogen has been reported to relieve damage in many disease models, and is a potential additive in drinking water to provide protective effects for patients as several clinical studies revealed. However, the absence of a dose–response relationship in the application of hydrogen is puzzling. We attempted to identify the dose–response relationship of hydrogen in alkaline electrolyzed drinking water through the aspirin induced gastric injury model.

Methods

In this study, hydrogen-rich alkaline water was obtained by adding H₂ to electrolyzed water at one atmosphere pressure. After 2 weeks of drinking, we detected the gastric mucosal damage together with MPO, MDA and 8-OHdG in rat aspirin induced gastric injury model.

Results

Hydrogen-dose dependent inhibition was observed in stomach mucosal. Under pH 8.5, 0.07, 0.22 and 0.84 ppm hydrogen exhibited a high correlation with inhibitory effects showed by erosion area, MPO activity and MDA content in the stomach. Gastric histology also demonstrated the inhibition of damage by hydrogen-rich alkaline water. However, 8-OHdG level in serum did not have significant hydrogen-dose dependent effect. pH 9.5 showed higher but not significant inhibitory response compared with pH 8.5.

Conclusions

Hydrogen is effective in relieving the gastric injury induced by aspirin-HCl, and the inhibitory effect is dose-dependent. The reason behind this may be that hydrogen-rich water directly interacted with the target tissue, while the hydrogen concentration in blood was buffered by liver glycogen, evoking a suppressed dose–response effect. Drinking hydrogen-rich water may protect healthy individuals from gastric damage caused by oxidative stress.

Hydrogen-rich saline ameliorates renal injury induced by unilateral ureteral obstruction in rats

Hydrogen has been demonstrated to have effective protection against tissue injuries caused by oxidative stress, inflammation, and apoptosis. This study investigated the efficacy of hydrogen-rich saline (HS) on the prevention of renal injury induced by unilateral ureteric obstruction (UUO) in rats. Male Sprague-Dawley rats were divided randomly into 4 groups: sham group, UUO group, UUO+saline group, and UUO+HS group. UUO was induced by ligation of the left ureter. 5ml/kg HRSS or saline was administered beginning 1day after UUO and for 10days thereafter. Rats were killed at 10days after UUO. Left kidneys were excised immediately for the tissue histologic examinations and biochemical assays. Renal injury scores in the UUO group and the UUO+saline group were significantly higher compared with those in the sham group. However, administration of HS significantly reduced the injury score. Apoptosis index was significantly increased in UUO group and the UUO+saline group. HS treatment also reduced the apoptosis index. Interstitial fibrosis and macrophage infiltration were obvious in UUO kidneys. However, HS treatment significantly reduced the fibrosis and infiltration of macrophage in UUO kidneys. Significant increase in the MDA level and decrease in the SOD activity were observed in UUO group and the UUO+saline group. MDA level of UUO+HS group was significantly reduced. In addition, SOD activity of was significantly improved after treatment of HS. The data provide a biochemical and histologic basis for HS acting as a novel therapeutic strategy for preventing the renal injury induced by UUO.

Hydrogen-rich medium suppresses the generation of reactive oxygen species, elevates the Bcl-2/Bax ratio and inhibits advanced glycation end product-induced apoptosis

The purpose of the present study was to determine whether using hydrogen-rich medium (HRM) to increase hydrogen levels in endothelial cells (ECs) protects ECs from apoptosis induced by advanced glycation end products (AGEs). The thoracic aorta was removed from 2-3-year-old Sprague-Dawley rats, and ECs were isolated and cultured. After culturing ECs in the presence of AGEs and/or with HRM for 24 h, Annexin V/7-AAD and TUNEL staining were carried out to detect apoptosis. Intracellular ROS were detected by fluorescent probe and quantified by flow cytometry. The expression of antioxidative enzymes (superoxide dismutase, glutathione peroxidase) was determined by real-time PCR analysis and enzymatic assay. The relative expression levels of Bcl-2 and Bax were analyzed by western blotting. The addition of AGEs increased the apoptosis of ECs in a concentration-dependent manner and HRM reduced the AGE (400 µg/ml)-induced apoptosis from 21.61±2.52 to 11.32±1.75%. HRM also significantly attenuated the AGE-induced intracellular ROS induction and decrease in the expression of antioxidative enzymes. In conclusion, hydrogen exhibits significant protective effects against AGE-induced EC injury possibly through reducing ROS generation, intracellular antioxidant enzyme system protection and elevation of the Bcl-2/Bax ratio.

H(2) gas improves functional outcome after cardiac arrest to an extent comparable to therapeutic hypothermia in a rat model

Background

All clinical and biological manifestations related to postcardiac arrest (CA) syndrome are attributed to ischemia–reperfusion injury in various organs including brain and heart. Molecular hydrogen (H₂) has potential as a novel antioxidant. This study tested the hypothesis that inhalation of H₂ gas starting at the beginning of cardiopulmonary resuscitation (CPR) could improve the outcome of CA.

Methods and Results

Ventricular fibrillation was induced by transcutaneous electrical epicardial stimulation in rats. After 5 minutes of the subsequent CA, rats were randomly assigned to 1 of 4 experimental groups at the beginning of CPR: mechanical ventilation (MV) with 2% N₂ and 98% O₂ under normothermia (37°C), the control group; MV with 2% H₂ and 98% O₂ under normothermia; MV with 2% N₂ and 98% O₂ under therapeutic hypothermia (TH), 33°C; and MV with 2% H₂ and 98% O₂ under TH. Mixed gas inhalation and TH continued until 2 hours after the return of spontaneous circulation (ROSC). H₂ gas inhalation yielded better improvement in survival and neurological deficit score (NDS) after ROSC to an extent comparable to TH. H₂ gas inhalation, but not TH, prevented a rise in left ventricular end-diastolic pressure and increase in serum IL-6 level after ROSC. The salutary impact of H₂ gas was at least partially attributed to the radical-scavenging effects of H₂ gas, because both 8-OHdG- and 4-HNE-positive cardiomyocytes were markedly suppressed by H₂ gas inhalation after ROSC.

Conclusions

Inhalation of H₂ gas is a favorable strategy to mitigate mortality and functional outcome of post-CA syndrome in a rat model, either alone or in combination with TH.

Molecular hydrogen and radiation protection

Molecular hydrogen (dihydrogen, H(2)) acts as a therapeutic antioxidant by selectively reducing hydroxyl radicals (•OH) and peroxynitrite (ONOO-). It has been well-known that ionising radiation (IR) causes oxidative damage and consequent apoptosis mainly due to the production of •OH that follows radiolysis of H(2)O. Our department reported the protective effect of H(2) in irradiated cells and mice for the first time, and this effect is well repeated by us and another laboratory in different experimental animal models. A randomised, placebo-controlled investigation also showed consumption of H(2) can improve the quality of life of patients treated with radiotherapy for liver tumours. These encouraging results suggested that H(2) has a potential as a radioprotective agent with efficacy and non-toxicity.