Application of Molecular Hydrogen as an Antioxidant in Responses to Ventilatory and Ergogenic Adjustments during Incremental Exercise in Humans.

We investigated effects of molecular hydrogen (H2) supplementation on acid-base status, pulmonary gas exchange responses, and local muscle oxygenation during incremental exercise. Eighteen healthy, trained subjects in a randomized, double-blind, crossover design received H2-rich calcium powder (HCP) (1500 mg/day, containing 2.544 µg/day of H2) or H2-depleted placebo (1500 mg/day) for three consecutive days. They performed cycling incremental exercise starting at 20-watt work rate, increasing by 20 watts/2 min until exhaustion. Breath-by-breath pulmonary ventilation (V˙E) and CO2 output (V˙CO2) were measured and muscle deoxygenation (deoxy[Hb + Mb]) was determined via time-resolved near-infrared spectroscopy in the vastus lateralis (VL) and rectus femoris (RF). Blood gases' pH, lactate, and bicarbonate (HCO3-) concentrations were measured at rest and 120-, 200-, and 240-watt work rates. At rest, the HCP group had significantly lower V˙E, V˙CO2, and higher HCO3-, partial pressures of CO2 (PCO2) versus placebo. During exercise, a significant pH decrease and greater HCO3- continued until 240-watt workload in HCP. The V˙E was significantly lower in HCP versus placebo, but HCP did not affect the gas exchange status of V˙CO2 or oxygen uptake (V˙O2). HCP increased absolute values of deoxy[Hb + Mb] at the RF but not VL. Thus, HCP-induced hypoventilation would lead to lower pH and secondarily impaired balance between O2 delivery and utilization in the local RF during exercise, suggesting that HCP supplementation, which increases the at-rest antioxidant potential, affects the lower ventilation and pH status during incremental exercise. HPC induced a significantly lower O2 delivery/utilization ratio in the RF but not the VL, which may be because these regions possess inherently different vascular/metabolic control properties, perhaps related to fiber-type composition.

Inhaled H2 or CO2 Do Not Augment the Neuroprotective Effect of Therapeutic Hypothermia in a Severe Neonatal Hypoxic-Ischemic Encephalopathy Piglet Model.

Hypoxic-ischemic encephalopathy (HIE) is still a major cause of neonatal death and disability as therapeutic hypothermia (TH) alone cannot afford sufficient neuroprotection. The present study investigated whether ventilation with molecular hydrogen (2.1% H2) or graded restoration of normocapnia with CO2 for 4 h after asphyxia would augment the neuroprotective effect of TH in a subacute (48 h) HIE piglet model. Piglets were randomized to untreated naïve, control-normothermia, asphyxia-normothermia (20-min 4%O2-20%CO2 ventilation; Tcore = 38.5 °C), asphyxia-hypothermia (A-HT, Tcore = 33.5 °C, 2-36 h post-asphyxia), A-HT + H2, or A-HT + CO2 treatment groups. Asphyxia elicited severe hypoxia (pO2 = 19 ± 5 mmHg) and mixed acidosis (pH = 6.79 ± 0.10). HIE development was confirmed by altered cerebral electrical activity and neuropathology. TH was significantly neuroprotective in the caudate nucleus but demonstrated virtually no such effect in the hippocampus. The mRNA levels of apoptosis-inducing factor and caspase-3 showed a ~10-fold increase in the A-HT group compared to naïve animals in the hippocampus but not in the caudate nucleus coinciding with the region-specific neuroprotective effect of TH. H2 or CO2 did not augment TH-induced neuroprotection in any brain areas; rather, CO2 even abolished the neuroprotective effect of TH in the caudate nucleus. In conclusion, the present findings do not support the use of these medical gases to supplement TH in HIE management.

Hydrogen gas inhalation improves delayed brain injury by alleviating early brain injury after experimental subarachnoid hemorrhage.

Molecular hydrogen (H2) protect neurons against reactive oxygen species and ameliorates early brain injury (EBI) after subarachnoid hemorrhage (SAH). This study investigated the effect of H2 on delayed brain injury (DBI) using the rat SAH + unilateral common carotid artery occlusion (UCCAO) model with the endovascular perforation method. 1.3% H2 gas (1.3% hydrogen premixed with 30% oxygen and balanced nitrogen) inhalation was performed on days 0 and 1, starting from anesthesia induction and continuing for 2 h on day 0, and starting from anesthesia induction and continuing for 30 min on day 1. EBI was assessed on the basis of brain edema, expression of S100 calcium-binding protein B (S100B), and phosphorylation of C-Jun N-terminal kinase on day 2, and neurological deficits on day 3. Reactive astrogliosis and severity of cerebral vasospasm (CV) were assessed on days 3 and 7. DBI was assessed on the basis of neurological deficits and neuronal cell death on day 7. EBI, reactive astrogliosis, and DBI were ameliorated in the H2 group compared with the control group. CV showed no significant improvement between the control and H2 groups. This study demonstrated that H2 gas inhalation ameliorated DBI by reducing EBI without improving CV in the rat SAH + UCCAO model.

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.

Aerosol inhalation of a hydrogen-rich solution restored septic renal function.

Sepsis-related acute kidney injury (AKI) is known to be caused by inflammation. We explored the renal protective effects of aerosol inhalation of a hydrogen-rich solution (HRS; hydrogen gas dissolved to saturation in saline) in a mouse model of septic AKI. Septic AKI was induced through 18 hours of cecal ligation and puncture. AKI occurred during the early stage of sepsis, as evidenced by increased blood urea nitrogen and serum creatinine levels, pathological changes, renal fibrosis and renal tubular epithelial cell apoptosis, accompanied by macrophage infiltration and M1 macrophage-associated pro-inflammatory cytokine (Il-6 and Tnf-α) generation in renal tissues. Aerosol inhalation of the HRS increased anti-inflammatory cytokine (Il-4 and Il-13) mRNA levels in renal tissues and promoted macrophage polarization to the M2 type, which generated additional anti-inflammatory cytokines (Il-10 and Tgf-ß). Ultimately, aerosol inhalation of HRS protected the kidneys and increased survival among septic mice. HRS was confirmed to promote M2 macrophage polarization in lipopolysaccharide-stimulated RAW 264.7 cells. The TGF-ß1 receptor inhibitor SB-431542 partly reversed the effects of HRS on renal function, fibrosis, tubular epithelial cell apoptosis and senescence in mice. Thus, HRS aerosol inhalation appears highly useful for renal protection and inflammation reduction in septic AKI.

Sustained release of bioactive hydrogen by Pd hydride nanoparticles overcomes Alzheimer's disease.

Oxidative stress-induced mitochondrial dysfunction plays an important role in the pathogenesis of Alzheimer's disease (AD). Hydrogen molecule, a special antioxidant, can selectively scavenge highly cytotoxic reactive oxygen species such as ·OH, exhibiting a potential to treat AD by reducing oxidative stress. However, there is no effective route to realize the continuous and efficient accumulation of administrated hydrogen in AD brain owing to its low solubility. Here, we develop the small-sized Pd hydride (PdH) nanoparticles for high payload of hydrogen and in situ sustained hydrogen release in AD brain. By virtue of the catalytic hydrogenation effect of Pd, the released hydrogen from PdH nanoparticles exhibits high bio-reductivity in favor of effectively scavenging cytotoxic ·OH in a self-catalysis way. Bio-reductive hydrogen is able to recover mitochondrial dysfunction, inhibit Aß generation and aggregation, block synaptic and neuronal apoptosis and promote neuronal energy metabolism by eliminating oxidative stress and activating the anti-oxidative pathway, consequently ameliorating the cognitive impairment in AD mice. The proposed hydrogen-releasing nanomedicine strategy would open a new window for the treatment of AD.

Effects of hydrogen-rich water on depressive-like behavior in mice.

Emerging evidence suggests that neuroinflammation and oxidative stress may be major contributors to major depressive disorder (MDD). Patients or animal models of depression show significant increase of proinflammatory cytokine interleukin-1ß (IL-1ß) and oxidative stress biomarkers in the periphery or central nervous system (CNS). Recent studies show that hydrogen selectively reduces cytotoxic oxygen radicals, and hydrogen-rich saline potentially suppresses the production of several proinflammatory mediators. Since current depression medications are accompanied by a wide spectrum of side effects, novel preventative or therapeutic measures with fewer side effects might have a promising future. We investigated the effects of drinking hydrogen-rich water on the depressive-like behavior in mice and its underlying mechanisms. Our study show that hydrogen-rich water treatment prevents chronic unpredictable mild stress (CUMS) induced depressive-like behavior. CUMS induced elevation in IL-1ß protein levels in the hippocampus, and the cortex was significantly attenuated after 4 weeks of feeding the mice hydrogen-rich water. Over-expression of caspase-1 (the IL-1ß converting enzyme) and excessive reactive oxygen species (ROS) production in the hippocampus and prefrontal cortex (PFC) was successfully suppressed by hydrogen-rich water treatment. Our data suggest that the beneficial effects of hydrogen-rich water on depressive-like behavior may be mediated by suppression of the inflammasome activation resulting in attenuated protein IL-1ß and ROS production.

Cigarette smoke exposure impairs reverse cholesterol transport which can be minimized by treatment of hydrogen-saturated saline.

BACKGROUND: Cigarette smoke (CS) exposure impaired plasma lipid profiles by modification of apolipoproteins. Hydrogen (H2) has been proved effective on reducing oxidative stress or improving HDL functionalities in animal models or metabolic syndrome volunteers. This study was undertaken to explore the effects of CS exposure on reverse cholesterol transport (RCT) and the antioxidative effects of H2 treatment against CS exposure in mice transgenic for human cholesteryl ester transfer protein (CETP). METHODS: [(3)H]-cholesterol-laden macrophages were injected intraperitoneally into mice, and the samples of blood, bile, liver, and feces were collected for radioactivity determination to evaluate RCT. [(3)H]-cholesterol-laden macrophages were incubated with HDL isolated from different groups of mice, and the samples of cell medium supernatants were collected for evaluating the HDL functionality to elicit cholesterol efflux. RESULTS: CS exposure significantly decreased plasma HDL cholesterol level (HDL-C) by 22% and increased LDL cholesterol level (LDL-C) by 21% compared with the control group (p < 0.05, p < 0.01), while H2 treatment significantly improved the CS-impaired levels of TC, LDL-C and HDL-C by 10, 27 and 31%, respectively, compared with the CS group (p < 0.05, p < 0.01 and p < 0.05). Besides, CS exposure significantly decreased [(3)H] tracer concentrations in liver, bile and feces by 17, 35 and 48%, respectively, compared with the control group (p < 0.05 for liver and feces), while H2 treatment significantly improved them by 21, 72% and 89%, respectively, compared with the CS group (all p < 0.05). Furthermore, CS exposure significantly decreased the HDL functionality to elicit cholesterol efflux by 26% (p < 0.05), while H2 treatment also improved it by 32% (p < 0.05). We did not find any significant alterations in protein expressions of RCT involved genes. CONCLUSIONS: These findings provided direct evidence supporting the notion that CS exposure in vivo impairs plasma lipid profiles, HDL functionalities and macrophage-to-feces RCT pathway in CETP transgenic mice, all of which can be minimized by treatment of H2-saturated saline.

Hydrogen water alleviates lung injury induced by one-lung ventilation.

BACKGROUND: With the development of thoracic surgeries, one-lung ventilation (OLV) has been routinely used to facilitate surgical exposure. However, OLV can cause lung injury during the surgical process and becomes an important factor affecting the outcomes. To date, effective treatments for the prevention of lung injury caused by OLV are lacking. 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 water consumption on the prevention of lung injury induced by OLV in rats. MATERIALS AND METHODS: Male Sprague-Dawley rats (n = 32, 240-260 g) were divided randomly into the following four groups: sham group, sham + H2 group, OLV group, OLV + H2 group. The rats drank hydrogen water or degassed hydrogen water for 4 wk before the operation and received OLV for 60 min and two-lung ventilation for 60 min. Lung tissues were assayed for wet-to-dry ratio, oxidative stress variables, proinflammatory cytokines, and hematoxylin-eosin staining. RESULTS: Hydrogen water consumption reduced wet-to-dry weight ratio, malondialdehyde and myeloperoxidase activity and decreased the concentration of TNF-α, IL-1ß, and IL-6 in the lung tissues compared with sham group and sham + H2 group. Hydrogen water consumption further attenuated NF-κB activation and caused histopathologic alterations. CONCLUSIONS: Our data demonstrated that hydrogen water consumption ameliorated OLV-induced lung injury, and it may exert its protective role by its anti-inflammation, antioxidation and reducing NF-κB activity in the lung tissues.

Inhalation of hydrogen gas ameliorates glyoxylate-induced calcium oxalate deposition and renal oxidative stress in mice.

The aim of this study is to evaluate the protective effect and underlying mechanism of hydrogen gas (H2) to glyoxylate induced renal calcium oxalate (CaOx) crystal deposition in mice. In present work, rodent renal CaOx crystal deposition model was introduced by intra-abdominal injection of glyoxylate (100 mg/kg/d) for 5 days. Two days before administration of glyoxylate, inhalation of H2 for 30 min per day was initiated and continued for 7 days. By the end of the study, the samples of 24 hours urine, serum and renal tissue were collected for biochemical and pathological assay. According to levels of urine calcium excretion, renal calcium deposition, a serum excretion of kidney injury molecule-1 (KIM-1) assay and a TUNEL assay, inhalation of H2 could successfully decrease the CaOx crystallizations and protect against renal injury. Crystal deposition in the kidneys is associated with oxidative stress, which was indicated by increased levels of renal malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG) and decreased activities of superoxide dismutase (SOD), glutathione (GSH) and catalase (CAT). These effects were reversed by a high-dose H2 pretreatment. The renal expressions of osteopontin (OPN), CD44, monocyte chemoattractant protein-1 (MCP-1) and interleukin-10 (IL-10) were markedly increased in glyoxylate-treated mice, and H2 significantly attenuated the increase of OPN, CD44 and MCP-1 but upregulated the expression of IL-10. Our findings demonstrate that inhalation of H2 reduces renal crystallization, renal oxidative injury and inflammation and it may be a candidate agent with few adverse effects for prevention of nephrolithiasis.

Molecular hydrogen in sports medicine: new therapeutic perspectives.

In the past 2 decades, molecular hydrogen emerged as a novel therapeutic agent, with antioxidant, anti-inflammatory and anti-apoptotic effects demonstrated in plethora of animal disease models and human studies. Beneficial effects of molecular hydrogen in clinical environment are observed especially in oxidative stress-mediated diseases, such as diabetes mellitus, brain stem infarction, rheumatoid arthritis, or neurodegenerative diseases. A number of more recent studies have reported that molecular hydrogen affects cell signal transduction and acts as an alkalizing agent, with these newly identified mechanisms of action having the potential to widen its application in clinical medicine even further. In particular, hydrogen therapy may be an effective and specific innovative treatment for exercise-induced oxidative stress and sports injury, with potential for the improvement of exercise performance. This review will summarize recent research findings regarding the clinical aspects of molecular hydrogen use, emphasizing its application in the field of sports medicine.

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.

Protective effects of hydrogen-rich saline on necrotizing enterocolitis in neonatal rats.

PURPOSE: The aim of this study was to test the hypothesis that hydrogen-rich saline (HRS) might have protective effects on the development of necrotizing enterocolitis (NEC) in a neonatal rat model. METHODS: NEC was induced in male newborn Sprague-Dawley rats by formula feeding, exposure to asphyxia and cold stress. Sixty-four rat pups were divided randomly into four groups: C+NS (n=11), C+H2 (n=11), NEC+NS (n=20), and NEC+H2 (n=22). Rats in the former two groups were mother-fed. Pups received intra-peritoneal injection of HRS (10 ml/kg, 10 min before asphyxia stress twice a day) or the same dose of normal saline. Rats were monitored until 96 h after birth. Body weight, histological NEC score, survival time, malondialdehyde, antioxidant capacity, inflammatory mediators, and mucosal integrity were assessed. RESULTS: HRS treatment maintained the body weight, reduced the incidence of NEC from 85% (17/20) to 54.5% (12/22), increased the survival rate from 25% (5/20) to 68.2% (15/22), and attenuated the severity of NEC. In addition, HRS inhibited the mRNA expression of pro-inflammatory mediators (inducible nitric oxide synthase, tumor necrosis factor-α, and interleukin-6), down-regulated lipid peroxidation, enhanced total antioxidant capacity, and prevented the increase of diamine oxidase in serum. However, no significant influence of HRS on the interleukin-10 mRNA expression was observed. CONCLUSIONS: HRS showed beneficial effects on neonatal rats with NEC via decreasing oxidative stress, increasing antioxidant capacity, suppressing inflammation, and preserving mucosal integrity.

Inhibitions by hydrogen-occluding silica microcluster to melanogenesis in human pigment cells and tyrosinase reaction.

We investigated the anti-melanogenetic efficacy of hydrogen-occluding silica microcluster (H2-Silica), which is a silsesquioxane-based compound with hydrogen interstitially embedded in a matrix of caged silica, against melanogenesis in HMV-II human melanoma cells and L-DOPA-tyrosinase reaction [EC1.14.18.1]. HMV-II cells were subjected to oxidative stress by ultraviolet ray-A (UVA) exposure of 3-times of 0.65 J/cm2 summed up to 1.95 J/cm2. After UVA irradiation, HMV-II cells were stimulated to produce melanin by 2.72-fold more abundantly than unirradiated control. When HMV-II cells were treated with H2-Silica of 20 ppm or kojic acid of 28.4 ppm before and after UVA-irradiation, the amount of melanin was repressed to 12.2% or 14.5% as compared to that of UVA-irradiated control, respectively. That is, H2-Silica exhibited a comparable efficacy to the whitening agent kojic acid. The H2-Silica could prevent melanogenesis in HMV-II cells by low-level doses at 1-10 ppm, and cell viability and apoptosis event did not change even by high-level doses at 100-1000 ppm. On the contrary, kojic acid was cytotoxic at the concentration of 14-28 ppm or more. By microscopic observation, H2-Silica suppressed such properties indicative of melanin-rich cells as cellular hypertrophy, cell process formation, and melanogenesis around the outside of nuclei. The enzymatic assay using L-DOPA and mushroom tyrosinase demonstrated that H2-Silica restrained UVA-mediated melanin formation owing to down-regulation of tyrosinase activity, which could be attributed to scavenging of free radicals and inhibition of L-DOPA-to-dopachrome oxidation by hydrogen released from H2-Silica. Thus H2-Silica has a potential to prevent melanin production against UVA and serves as a skin-lightening ingredient for supplements or cosmetics.

Effect of supplementation with hydrogen-rich water in patients with interstitial cystitis/painful bladder syndrome.

OBJECTIVE: To investigate the efficacy of hydrogen-rich water for the treatment of patients with interstitial cystitis/painful bladder syndrome (IC/PBS). METHODS: We conducted a prospective, randomized, double-blind, placebo-controlled clinical trial of hydrogen-rich water in patients with IC/PBS. Inclusion criteria were stable symptoms of IC/PBS for ≥ 12 weeks after bladder hydrodistension, Interstitial Cystitis Symptom Index score of ≥ 7 and bladder pain (question 4 on Interstitial Cystitis Symptom Index) of ≥ 4. They were randomized by a 2:1 ratio to receive hydrogen-rich water or placebo water for 8 weeks. The symptoms were assessed using the Interstitial Cystitis Symptom Index, Interstitial Cystitis Problem Index, Parsons' Pelvic Pain and Urgency/Frequency Patient Symptom Scale, visual analog scale bladder pain scores, and a standard 3-day voiding diary. The primary outcome was improvement of patient-reported symptoms evaluated after treatment. RESULTS: A total of 30 participants (29 women and 1 man, age 64.0 ± 14.8 years) were enrolled in the present study, and 2 patients (both women) were withdrawn from the study. The score of bladder pain was significantly reduced in both groups. However, the effect of hydrogen-rich water on symptoms was not significantly different from that of placebo, although supplementation with hydrogen-rich water was extremely effective in improving the bladder pain score in 11% of the patients. CONCLUSION: The results of the present study do not support the use of supplementation with hydrogen-rich water for treating patients with IC/PBS.

Inhalation gases or gaseous mediators as neuroprotectants for cerebral ischaemia.

Ischaemic stroke is one of the leading causes of morbidity and mortality worldwide. While recombinant tissue plasminogen activator can be administered to produce thrombolysis and restore blood flow to the ischaemic brain, therapeutic benefit is only achieved in a fraction of the subset of patients eligible for fibrinolytic intervention. Neuroprotective therapies attempting to restrict the extent of brain injury following cerebral ischaemia have not been successfully translated into the clinic despite overwhelming pre-clinical evidence of neuroprotection. Therefore, an adequate treatment for the majority of acute ischaemic stroke patients remains elusive. In the stroke literature, the use of therapeutic gases has received relatively little attention. Gases such as hyperbaric and normobaric oxygen, xenon, hydrogen, helium and argon all possess biological effects that have shown to be neuroprotective in pre-clinical models of ischaemic stroke. There are significant advantages to using gases including their relative abundance, low cost and feasibility for administration, all of which make them ideal candidates for a translational therapy for stroke. In addition, modulating cellular gaseous mediators including nitric oxide, carbon monoxide, and hydrogen sulphide may be an attractive option for ischaemic stroke therapy. Inhalation of these gaseous mediators can also produce neuroprotection, but this strategy remains to be confirmed as a viable therapy for ischaemic stroke. This review highlights the neuroprotective potential of therapeutic gas therapy and modulation of gaseous mediators for ischaemic stroke. The therapeutic advantages of gaseous therapy offer new promising directions in breaking the translational barrier for ischaemic stroke.

Protective effects of hydrogen-rich saline against erectile dysfunction in a streptozotocin induced diabetic rat model.

PURPOSE: Hydrogen has antioxidative stress and anti-inflammatory effects. We investigated the effect of hydrogen on erectile dysfunction in streptozotocin induced diabetic rats. MATERIALS AND METHODS: Diabetes was induced in Sprague-Dawley® rats by a single intravenous injection of streptozotocin. Diabetic rats were then randomized to a diabetes mellitus group and to a diabetic group that received hydrogen saline. The latter 8 rats were fed saturated hydrogen saline (5 ml/kg per day) by intragastric administration for 8 weeks. At the end of week 8 erectile function was assessed by measuring the increase in intracavernous pressure after cavernous nerve electrostimulation. We measured nitric oxide synthase activity, and malondialdehyde, 8-hydroxydeoxyguanosine, and nitrite and nitrate in the corpus cavernosum. eNOS protein immunolocalization in cavernous tissues was detected by immunohistochemistry. eNOS, Bcl-2 and Bax protein expression was determined by Western blot. We determined eNOS, Bcl-2 and Bax mRNA using real-time reverse transcriptase-polymerase chain reaction. RESULTS: Oxidative stress is involved in the pathophysiological mechanism of erectile dysfunction. Maximum intracavernous pressure in diabetic rats decreased significantly compared to controls and increased significantly compared to untreated diabetic rats after hydrogen-rich saline treatment. Decreased nitric oxide synthase activity, nitrite and nitrate, and eNOS expression as well as increased 8-hydroxydeoxyguanosine and malondialdehyde were found in the diabetic group compared to controls. Hydrogen-rich saline improved nitric oxide synthase activity, and malondialdehyde, nitrite and nitrate, and 8-hydroxydeoxyguanosine levels in the diabetic rat corpus cavernosum. Decreased eNOS in diabetic rats was ameliorated by hydrogen-rich saline. Also, apoptosis in the diabetic rat corpus cavernosum was significantly enhanced compared with controls. Hydrogen-rich saline therapy may decrease apoptosis in cavernous tissues and it ameliorated erectile dysfunction in diabetic rats by inhibiting oxidative stress and apoptosis. CONCLUSIONS: Hydrogen-rich saline effectively improved erectile function in a streptozotocin induced diabetic rat model of erectile dysfunction.

The neuroprotective effects of intraperitoneal injection of hydrogen in rabbits with cardiac arrest.

OBJECTIVE: The purpose of this study was to investigate the neuroprotective effects of intraperitoneal injection of hydrogen (H2) in rabbits with cardiac arrest (CA). METHODS: A rabbit model of CA was established by the delivery of alternating current between the esophagus and chest wall to induce ventricular fibrillation. Before CA, the animals were randomly divided into four groups: a sham group (no CA), a CA group, a CA + low dose (10 ml/kg) H2 group (CA + H2 group 1), and a CA + high dose (20 ml/kg) H2 group (CA + H2 group 2). In the first experiment, animals were observed for 72 h after the restoration of spontaneous circulation (ROSC). The neurological scores were assessed at 24, 48 and 72 h after ROSC. The rabbits that survived until 72 h were sacrificed using an overdose of anesthetic, and the brain tissues were collected and Nissl-stained to observe nerve cell damage in the hippocampal CA1 area. In addition, TUNEL assay was performed to detect apoptosis. In the second experiment, animals were observed for 6h after ROSC. Blood samples and brain hippocampal tissues were collected, and differences in oxidative stress indicators were compared among the four groups. RESULTS: Intraperitoneal injection of H2 improved the 72-h survival rate and neurological scores, reduced neuronal injury and inhibited neuronal apoptosis. Intraperitoneal injection of H2 reduced oxidative stress indicators in the plasma and hippocampal tissues and enhanced antioxidant enzyme activity. No significant difference was observed between the two CA groups treated with different doses of H2. CONCLUSIONS: Intraperitoneal injection of H2 is a novel hydrogen administration method and can reduce cerebral ischemia-reperfusion injury and improve the prognosis of cardiopulmonary cerebral resuscitation in a rabbit model of CA.

Hydrogen-rich saline protects against oxidative damage and cognitive deficits after mild traumatic brain injury.

Oxidative stress is the principal factor in traumatic brain injury (TBI) that initiates events that result in protracted neuronal dysfunction and remodeling. Importantly, antioxidants can protect the brain against oxidative damage and modulate the capacity of the brain to cope with synaptic dysfunction and cognitive impairment. However, no studies have investigated the effects of hydrogen-rich saline on cognitive deficits after TBI. In the present study, rats with fluid percussion injury (FPI) were used to investigate the protective effects of hydrogen-rich saline. The results showed that hydrogen-rich saline reduced the level of malondialdehyde (MDA) and elevated the level of silent information regulator 2 (Sir2). In addition, treatment with hydrogen-rich saline, which elevated the levels of molecules associated with brain-derived neurotropic factor (BDNF)-mediated synaptic plasticity, improved cognitive performance in the Morris water maze after mild TBI. These results suggest that hydrogen-rich saline can protect the brain against the deleterious effects of mild TBI on synaptic plasticity and cognition and that hydrogen-rich saline could be an effective therapeutic strategy for patients with cognitive deficits after TBI.

Hydrogen gas ameliorates oxidative stress in early brain injury after subarachnoid hemorrhage in rats.

OBJECTIVE: Hydrogen gas has been demonstrated to neutralize free radicals and reduce oxidative stress recently. Our objective was to determine the therapeutic effect of H2 inhalation and its antioxidative activity on early brain injury after subarachnoid hemorrhage. DESIGN: Controlled in vivo laboratory study. SETTING: Animal research laboratory. SUBJECTS: One hundred thirty-seven adult male Sprague-Dawley rats weighing 280-350 g. INTERVENTIONS: Subarachnoid hemorrhage was induced by endovascular perforation method in rats. Subarachnoid hemorrhage rats were treated with 2.9% hydrogen gas inhaled for 2 hrs after perforation. At 24 and 72 hrs, mortality, body weight, neurologic deficits, and brain water content were assessed. Blood-brain barrier permeability and apoptosis were also measured at 24 hrs. To investigate the antioxidative activity of hydrogen gas, the expression of malondialdehyde, nitrotyrosine, and 8-hydroxyguanosine, which are oxidative markers of lipid, protein, and DNA damage, respectively, were measured at 24 hrs. MEASUREMENTS AND MAIN RESULTS: Hydrogen gas significantly alleviated brain edema and blood-brain barrier disruption, reduced apoptosis, and improved neurologic function at 24 hrs but not 72 hrs after subarachnoid hemorrhage. These effects were associated with the amelioration of oxidative injury of lipid, protein, and DNA. CONCLUSIONS: Hydrogen gas could exert its neuroprotective effect against early brain injury after subarachnoid hemorrhage by its antioxidative activity.