An injectable magnesium-loaded hydrogel releases hydrogen to promote osteoporotic bone repair via ROS scavenging and immunomodulation.

Background: The repair of osteoporotic bone defects remains challenging due to excessive reactive oxygen species (ROS), persistent inflammation, and an imbalance between osteogenesis and osteoclastogenesis. Methods: Here, an injectable H2-releasing hydrogel (magnesium@polyethylene glycol-poly(lactic-co-glycolic acid), Mg@PEG-PLGA) was developed to remodel the challenging bone environment and accelerate the repair of osteoporotic bone defects. Results: This Mg@PEG-PLGA gel shows excellent injectability, shape adaptability, and phase-transition ability, can fill irregular bone defect areas via minimally invasive injection, and can transform into a porous scaffold in situ to provide mechanical support. With the appropriate release of H2 and magnesium ions, the 2Mg@PEG-PLGA gel (loaded with 2 mg of Mg) displayed significant immunomodulatory effects through reducing intracellular ROS, guiding macrophage polarization toward the M2 phenotype, and inhibiting the IκB/NF-κB signaling pathway. Moreover, in vitro experiments showed that the 2Mg@PEG-PLGA gel inhibited osteoclastogenesis while promoting osteogenesis. Most notably, in animal experiments, the 2Mg@PEG-PLGA gel significantly promoted the repair of osteoporotic bone defects in vivo by scavenging ROS and inhibiting inflammation and osteoclastogenesis. Conclusions: Overall, our study provides critical insight into the design and development of H2-releasing magnesium-based hydrogels as potential implants for repairing osteoporotic bone defects.

Hydrogen alleviates hypoxic-ischaemic brain damage in neonatal rats by inhibiting injury of brain pericytes.

Hypoxia-ischaemia (HI) can induce the death of cerebrovascular constituent cells through oxidative stress. Hydrogen is a powerful antioxidant which can activate the antioxidant system. A hypoxia-ischaemia brain damage (HIBD) model was established in 7-day-old SD rats. Rats were treated with different doses of hydrogen-rich water (HRW), and brain pericyte oxidative stress damage, cerebrovascular function and brain tissue damage were assessed. Meanwhile, in vitro-cultured pericytes were subjected to oxygen-glucose deprivation and treated with different concentrations of HRW. Oxidative injury was measured and the molecular mechanism of how HRW alleviated oxidative injury of pericytes was also examined. The results showed that HRW significantly attenuated HI-induced oxidative stress in the brain pericytes of neonatal rats, partly through the Nrf2-HO-1 pathway, further improving cerebrovascular function and reducing brain injury and dysfunction. Furthermore, HRW is superior to a single-cell death inhibitor for apoptosis, ferroptosis, parthanatos, necroptosis and autophagy and can better inhibit HI-induced pericyte death. The liver and kidney functions of rats were not affected by present used HRW dose. This study elucidates the role and mechanism of hydrogen in treating HIBD from the perspective of pericytes, providing new theoretical evidence and mechanistic references for the clinical application of hydrogen in neonatal HIE.

Inhalation of hydrogen gas protects against mitomycin-induced pulmonary veno-occlusive disease.

BACKGROUND: As a subtype of pulmonary hypertension (PH), pulmonary veno-occlusive disease (PVOD) is devastating and life-threatening disease without effective therapy. Hydrogen has been reported to exhibits antioxidant and anti-inflammatory effects in a rat model induced by monocrotaline of PH. In this study, we investigated the effects of inhaled hydrogen gas on the prevention and treatment of PVOD induced by mitomycin C (MMC) in rats. METHODS: PVOD was induced in female Sprague-Dawley rats through intraperitoneal injection of MMC at a concentration of 3 mg·kg- 1·wk- 1 for 2 weeks. Inhalation of hydrogen gas (H2) was administered through a designed rat cage concurrently or two weeks after MMC administration. The severity of PVOD was assessed by using hemodynamic measurements and histological analysis. The expression levels of general control nonderepressible 2 (GCN2), nuclear factor erythroid 2-related factor-2 (Nrf2), heme oxygenase-1 (HO-1) and endothelial-to-mesenchymal transition (EndoMT) related proteins in lung tissue were measured. Levels of lipid peroxidation pro-inflammatory cytokines in serum were determined. RESULTS: Inhaled H2 improved hemodynamics and right heart function, reversed right ventricular hypertrophy, and prevented pulmonary vessel reconstitution in both prevention and treatment approaches. It decreased malondialdehyde (MDA) levels in the serum and the expression of NADPH oxidase 1 (NOX-1) in lung tissue. It regulated Nrf2/HO-1 signaling pathway and anti-inflammatory factor GCN2 in lung tissue, accompanied by a decrease in macrophages and pro-inflammatory cytokines. Our data suggested that H2 inhalation effectively countered EndoMT induced by MMC, as evidenced by the detection of endothelial markers (e.g., VE-cadherin and CD31) and mesenchymal markers (e.g., vimentin and fibronectin). Further research revealed that H2 preserved p-Smad3 and induced p-Smad1/5/9. CONCLUSION: Inhalation of H2 effectively inhibits the pathogenesis of PVOD induced by MMC in rats. This inhibitory effect may be attributed to the antioxidant and anti-inflammatory properties of H2.

Hydrogen-Rich Alkaline Water Supplementation Restores a Healthy State and Redox Balance in H2O2-Treated Mice.

Water is a major requirement for our bodies, and alkaline water has induced an antioxidant response in a model of natural aging. A series of recent reports have shown that aging is related to reduced water intake. Hydrogen-rich water has been suggested to exert a general antioxidant effect in relation to both improving lifestyle and preventing a series of diseases. Here, we wanted to investigate the effect of the daily intake of hydrogen-rich alkaline water (HAW) in counteracting the redox imbalance induced in a model of H2O2-treated mice. Mice were treated with H2O2 for two weeks and either left untreated or supplied with HAW. The results show that HAW induced a reduction in the ROS plasmatic levels that was consistent with the increase in the circulating glutathione. At the same time, the reduction in plasmatic 8-hydroxy-2'-deoxyguanosine was associated with reduced DNA damage in the whole body. Further analysis of the spleen and bone marrow cells showed a reduced ROS content consistent with a significantly reduced mitochondrial membrane potential and superoxide accumulation and an increase in spontaneous proliferation. This study provides evidence for a clear preventive and curative effect of HAW in a condition of systemic toxic condition and redox imbalance.

Effect of Orally Ingested Water Containing H2-Filled Ultrafine Bubbles (UFBs) on Ethanol-Induced Oxidative Stress in Rats.

Ultrafine bubbles (UFBs), which are bubbles with diameters of less than 1 µm, are widely recognized for their ability to exist stably in liquid as a result of the effects of Brownian motion. In this study, we focused on hydrogen, known for its antioxidant potential, and explored the function of H2-filled UFBs, which encapsulate hydrogen, to determine their potential use as oral carriers for the delivery bioactive gases to living organisms. To this end, rats were orally administered ethanol to induce hepatic oxidative stress, and the effects of drinking H2-filled UFBs (H2 NanoGAS®) water for two weeks were evaluated to assess the reduction of oxidative stress. Continuous alcohol consumption was found to significantly increase the blood lipid peroxidation levels in the control group, confirming the induction of oxidative stress. An increase in blood lipid peroxidation was significantly inhibited by the consumption of concentrated H2 NanoGAS® (C-HN) water. Furthermore, the measurement of mitochondrial activity in the liver revealed that drinking H2 NanoGAS® water helped to maintain at a normal level and/or boosted the functional activity of the electron transport system in mitochondria affected by ethanol intake. To our knowledge, this study is the first to provide evidence for the use of orally ingested UFBs as carriers for the delivery gases to tissues, thereby exerting their physiological activity in the body. Our findings highlight the potential for the application of UFBs to various physiologically active gases and their utilization in the medical field in the future.

A hydrogen generator composed of poly (lactic-co-glycolic acid) nanofibre membrane loaded iron nanoparticles for infectious diabetic wound repair.

Diabetic wound, which is chronic skin disease, poses a significant challenge in clinical practice because of persistent inflammation and impaired angiogenesis. Recently, hydrogen has emerged as a novel therapeutic agent due to its superior antioxidant and anti-inflammatory properties. In this study, we engineered a poly (lactic-co-glycolic acid) (PLGA) electrospun nanofibre membrane loaded with citric acid (CA) and iron (Fe) nanoparticles, referred to as Fe@PLGA + CA. Our in vitro assays demonstrated that the Fe@PLGA + CA membrane continuously generated and released hydrogen molecules via a chemical reaction between Fe and CA in an acidic microenvironment created by CA. We also discovered that hydrogen can ameliorate fibroblast migration disorders by reducing the levels of matrix metalloproteinase 9 (MMP9). Furthermore, we confirmed that hydrogen can scavenge or biochemically neutralise accumulated reactive oxygen species (ROS), inhibit pro-inflammatory responses, and induce anti-inflammatory reactions. This, in turn, promotes vessel formation, wound-healing and accelerates skin regeneration. These findings open new possibilities for using elemental iron in skin dressings and bring us one step closer to implementing hydrogen-releasing biomedical materials in clinical practice.

Sustained Release of Hydrogen and Magnesium Ions Mediated by a Foamed Gelatin-Methacryloyl Hydrogel for the Repair of Bone Defects in Diabetes.

Diabetic bone defects, exacerbated by hyperglycemia-induced inflammation and oxidative stress, present significant therapeutic challenges. This study introduces a novel injectable scaffold, MgH2@PLGA/F-GM, consisting of foamed gelatin-methacryloyl (GelMA) and magnesium hydride (MgH2) microspheres encapsulated in poly(lactic-co-glycolic acid) (PLGA). This scaffold is uniquely suited for diabetic bone defects, conforming to complex shapes and fostering an environment conducive to tissue regeneration. As it degrades, Mg(OH)2 is released and dissolved by PLGA's acidic byproducts, releasing therapeutic Mg2+ ions. These ions are instrumental in macrophage phenotype modulation, inflammation reduction, and angiogenesis promotion, all vital for diabetic bone healing. Additionally, hydrogen (H2) released during degradation mitigates oxidative stress by diminishing reactive oxygen species (ROS). This multifaceted approach not only reduces ROS and inflammation but also enhances M2 macrophage polarization and cell migration, culminating in improved angiogenesis and bone repair. This scaffold presents an innovative strategy for addressing the complexities of diabetic bone defect treatment.

Poly(ionic liquid)-Flocculated Chlorella Loading Bactericidal and Antioxidant Hydrogel as a Biological Hydrogen Therapy for Diabetic Wound Dressing.

Infection and oxidative stress seriously hinder the healing of diabetic wounds, resulting in various serious health and clinical problems. Herein, a sustainable biological hydrogen (H2)-producing hyaluronic acid-based hydrogel patch (HAP-Chl) was constructed by loading an imidazolium-based poly(ionic liquid) (PIL) flocculated live Chlorella as a diabetic wound dressing. The PIL can flocculate Chlorella through electrostatic interactions between PIL and Chlorella to form Chlorella agglomerates, endowing the Chlorella in the central agglomerates with the ability to continuously produce H2 for 24 h under mild conditions. Combining the membrane disruption-related bactericidal mechanism of PIL and the antioxidant properties of the produced H2, HAP-Chl was determined to be antibacterial and antioxidant. In addition to exhibiting biocompatible and nontoxic activities, subsequent Staphylococcus aureus-infected chronic wound studies revealed that HAP-Chl is capable of promoting the healing of chronic wounds by effectively killing bacteria, reducing extensive ROS, relieving inflammation, and promoting the deposition of mature collagen and angiogenesis. This study provides a new strategy for constructing an in situ sustainable H2-producing hydrogel, enabling the formation of novel antibacterial and antioxidant material platforms with potential for wound dressing applications.

Hydrogen-rich water alleviates constipation by attenuating oxidative stress through the sirtuin1/nuclear factor-erythroid-2-related factor 2/heme oxygenase-1 signaling pathway.

BACKGROUND: Constipation, a highly prevalent functional gastrointestinal disorder, induces a significant burden on the quality of patients' life and is associated with substantial healthcare expenditures. Therefore, identifying efficient therapeutic modalities for constipation is of paramount importance. Oxidative stress is a pivotal contributor to colonic dysmotility and is the underlying pathology responsible for constipation symptoms. Consequently, we postulate that hydrogen therapy, an emerging and promising intervention, can serve as a safe and efficacious treatment for constipation. AIM: To determine whether hydrogen-rich water (HRW) alleviates constipation and its potential mechanism. METHODS: Constipation models were established by orally loperamide to Sprague-Dawley rats. Rats freely consumed HRW, and were recorded their 24 h total stool weight, fecal water content, and charcoal propulsion rate. Fecal samples were subjected to 16S rDNA gene sequencing. Serum non-targeted metabolomic analysis, malondialdehyde, and superoxide dismutase levels were determined. Colonic tissues were stained with hematoxylin and eosin, Alcian blue-periodic acid-Schiff, reactive oxygen species (ROS) immunofluorescence, and immunohistochemistry for cell growth factor receptor kit (c-kit), PGP 9.5, sirtuin1 (SIRT1), nuclear factor-erythroid-2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1). Quantitative real-time PCR and western blot analysis were conducted to determine the expression level of SIRT1, Nrf2 and HO-1. A rescue experiment was conducted by intraperitoneally injecting the SIRT1 inhibitor, EX527, into constipated rats. NCM460 cells were induced with H2O2 and treated with the metabolites to evaluate ROS and SIRT1 expression. RESULTS: HRW alleviated constipation symptoms by improving the total amount of stool over 24 h, fecal water content, charcoal propulsion rate, thickness of the intestinal mucus layer, c-kit expression, and the number of intestinal neurons. HRW modulated intestinal microbiota imbalance and abnormalities in serum metabolism. HRW could also reduce intestinal oxidative stress through the SIRT1/Nrf2/HO-1 signaling pathway. This regulatory effect on oxidative stress was confirmed via an intraperitoneal injection of a SIRT1 inhibitor to constipated rats. The serum metabolites, ß-leucine (ß-Leu) and traumatic acid, were also found to attenuate H2O2-induced oxidative stress in NCM460 cells by up-regulating SIRT1. CONCLUSION: HRW attenuates constipation-associated intestinal oxidative stress via SIRT1/Nrf2/HO-1 signaling pathway, modulating gut microbiota and serum metabolites. ß-Leu and traumatic acid are potential metabolites that upregulate SIRT1 expression and reduce oxidative stress.

Molecular hydrogen promotes retinal vascular regeneration and attenuates neovascularization and neuroglial dysfunction in oxygen-induced retinopathy mice.

BACKGROUND: Retinopathy of Prematurity (ROP) is a proliferative retinal vascular disease occurring in the retina of premature infants and is the main cause of childhood blindness. Nowadays anti-VEGF and retinal photocoagulation are mainstream treatments for ROP, but they develop a variety of complications. Hydrogen (H2) is widely considered as a useful neuroprotective and antioxidative therapeutic method for hypoxic-ischemic disease without toxic effects. However, whether H2 provides physiological angiogenesis promotion, neovascularization suppression and glial protection in the progression of ROP is largely unknown.This study aims to investigate the effects of H2 on retinal angiogenesis, neovascularization and neuroglial dysfunction in the retinas of oxygen-induced retinopathy (OIR) mice. METHODS: In this study, mice that were seven days old and either wild-type (WT) or Nrf2-deficient (Nrf2-/-) were exposed to 75% oxygen for 5 days and then returned to normal air conditions. Different stages of hydrogen gas (H2) inhalation were administered. Vascular obliteration, neovascularization, and blood vessel leakage were analyzed and compared. To count the number of neovascularization endothelial nuclei, routine HE staining of retinal sections was conducted. Immunohistochemistry was performed using DyLight 594 labeled GSL I-isolectin B4 (IB4), as well as primary antibodies against proliferating cell nuclear antigen (PCNA), glial fibrillary acidic protein (GFAP), and Iba-1. Western blots were used to measure the expression of NF-E2-related factor 2 (Nrf2), vascular endothelial growth factor (VEGF), Notch1, Dll4, and HIF-1α. Additionally, the expression of target genes such as NQO1, HO-1, Notch1, Hey1, Hey2, and Dll4 was measured. Human umbilical vein endothelial cells (HUVECs) treated with H2 under hypoxia were used as an in vitro model. RT-PCR was used to evaluate the mRNA expression of Nrf2, Notch/Dll4, and the target genes. The expression of reactive oxygen species (ROS) was observed using immunofluorescence staining. RESULTS: Our results indicate that 3-4% H2 does not disturb retinal physiological angiogenesis, but ameliorates vaso-obliteration and neovascularization in OIR mice. Moreover, H2 prevents the decreased density and reverses the morphologic and functional changes in retinal astrocytes caused by oxygen-induced injury. In addition, H2 inhalation reduces microglial activation, especially in the area of neovascularization in OIR mice. H2 plays a protective role in vascular regeneration by promoting Nrf2 activation and suppressing the Dll4-induced Notch signaling pathway in vivo. Also, H2 promotes the proliferation of HUVECs under hypoxia by negatively regulating the Dll4/Notch pathway and reducing ROS levels through Nrf2 pathway aligning with our findings in vivo.Moreover, the retinal oxygen-sensing mechanisms (HIF-1α/VEGF) are also involved in hydrogen-mediated retinal revascularization and neovascularization suppression. CONCLUSIONS: Collectively, our results indicate that H2 could be a promising therapeutic agent for POR treatment and that its beneficial effect in human ROP might involve the activation of the Nrf2-Notch axis as well as HIF-1α/VEGF pathways.

Evaluation of the effect of enriched hydrogen saline solution on distant organ (lung) damage in skeletal muscle ischemia reperfusion in rats.

INTRODUCTION: Ischemia-reperfusion (IR) injury is a major concern that frequently occurs during vascular surgeries. Hydrogen-rich saline (HRS) solution exhibits antioxidant and anti-inflammatory properties. This study aimed to examine the effects of HRS applied before ischemia in the lungs of rats using a lower extremity IR model. MATERIAL AND METHODS: After approval was obtained from the ethics committee, 18 male Wistar albino rats weighing 250-280 g were randomly divided into three groups: control (C), IR and IR-HRS. In the IR and IR-HRS groups, an atraumatic microvascular clamp was used to clamp the infrarenal abdominal aorta, and skeletal muscle ischemia was induced. After 120 min, the clamp was removed, and reperfusion was achieved for 120 min. In the IR-HRS group, HRS was administered intraperitoneally 30 min before the procedure. Lung tissue samples were examined under a light microscope and stained with hematoxylin-eosin (H&E). Malondialdehyde (MDA) levels, total sulfhydryl (SH) levels, and histopathological parameters were evaluated in the tissue samples. RESULTS: MDA and total SH levels were significantly higher in the IR group than in the control group (p < 0.0001 and p = 0.001, respectively). MDA and total SH levels were significantly lower in the IR-HRS group than in the IR group (p < 0.0001 and p = 0.013, respectively). A histopathological examination revealed that neutrophil infiltration/aggregation, alveolar wall thickness, and total lung injury score were significantly higher in the IR group than in the control group (p < 0.0001, p = 0.001, and p < 0.0001, respectively). Similarly, alveolar wall thickness and total lung injury scores were significantly higher in the IR-HRS group than in the control group (p = 0.009 and p = 0.004, respectively). A statistically significant decrease was observed in neutrophil infiltration/aggregation and total lung injury scores in the IR-HRS group compared to those in the IR group (p = 0.023 and p = 0.022, respectively). CONCLUSION: HRS at a dose of 20 mg/kg, administered intraperitoneally 30 min before ischemia in rats, reduced lipid peroxidation and oxidative stress, while also reducing IR damage in lung histopathology. We believe that HRS administered to rats prior to IR exerts a lung-protective effect.

Neuroprotective effects of Si-based hydrogen-producing agent on 6-hydroxydopamine-induced neurotoxicity in juvenile mouse model.

Neurotoxins have been extensively investigated, particularly in the field of neuroscience. They induce toxic damage, oxidative stress, and inflammation on neurons, triggering neuronal dysfunction and neurodegenerative diseases. Here we demonstrate the neuroprotective effect of a silicon (Si)-based hydrogen-producing agent (Si-based agent) in a juvenile neurotoxic mouse model induced by 6-hydroxydopamine (6-OHDA). The Si-based agent produces hydrogen in bowels and functions as an antioxidant and anti-inflammatory agent. However, the effects of the Si-based agent on neural degeneration in areas other than the lesion and behavioral alterations caused by it are largely unknown. Moreover, the neuroprotective effects of Si-based agent in the context of lactation and use during infancy have not been explored in prior studies. In this study, we show the neuroprotective effect of the Si-based agent on 6-OHDA during lactation period and infancy using the mouse model. The Si-based agent safeguards against the degradation and neuronal cell death of dopaminergic neurons and loss of dopaminergic fibers in the striatum (STR) and ventral tegmental area (VTA) caused by 6-OHDA. Furthermore, the Si-based agent exhibits a neuroprotective effect on the length of axon initial segment (AIS) in the layer 2/3 (L2/3) neurons of the medial prefrontal cortex (mPFC). As a result, the Si-based agent mitigates hyperactive behavior in a juvenile neurotoxic mouse model induced by 6-OHDA. These results suggest that the Si-based agent serves as an effective neuroprotectant and antioxidant against neurotoxic effects in the brain, offering the possibility of the Si-based agent as a neuroprotectant for nervous system diseases.

Hydrogen gas inhalation ameliorates LPS-induced BPD by inhibiting inflammation via regulating the TLR4-NFκB-IL6/NLRP3 signaling pathway in the placenta.

INTRODUCTION: Hydrogen (H2) is regarded as a novel therapeutic agent against several diseases owing to its inherent biosafety. Bronchopulmonary dysplasia (BPD) has been widely considered among adverse pregnancy outcomes, without effective treatment. Placenta plays a role in defense, synthesis, and immunity, which provides a new perspective for the treatment of BPD. This study aimed to investigate if H2 reduced the placental inflammation to protect the neonatal rat against BPD damage and potential mechanisms. METHODS: We induced neonatal BPD model by injecting lipopolysaccharide (LPS, 1 µg) into the amniotic fluid at embryonic day 16.5 as LPS group. LPS + H2 group inhaled 42% H2 gas (4 h/day) until the samples were collected. We primarily analyzed the neonatal outcomes and then compared inflammatory levels from the control group (CON), LPS group and LPS + H2 group. HE staining was performed to evaluate inflammatory levels. RNA sequencing revealed dominant differentially expressed genes. Bioinformatics analysis (GO and KEGG) of RNA-seq was applied to mine the signaling pathways involved in protective effect of H2 on the development of LPS-induced BPD. We further used qRT-PCR, Western blot and ELISA methods to verify differential expression of mRNA and proteins. Moreover, we verified the correlation between the upstream signaling pathways and the downstream targets in LPS-induced BPD model. RESULTS: Upon administration of H2, the inflammatory infiltration degree of the LPS-induced placenta was reduced, and infiltration significantly narrowed. Hydrogen normalized LPS-induced perturbed lung development and reduced the death ratio of the fetus and neonate. RNA-seq results revealed the importance of inflammatory response biological processes and Toll-like receptor signaling pathway in protective effect of hydrogen on BPD. The over-activated upstream signals [Toll-like receptor 4 (TLR4), nuclear factor kappa-B p65 (NF-κB p65), Caspase1 (Casp1) and NLR family pyrin domain containing 3 (NLRP3) inflammasome] in LPS placenta were attenuated by H2 inhalation. The downstream targets, inflammatory cytokines/chemokines [interleukin (IL)-6, IL-18, IL-1ß, C-C motif chemokine ligand 2 (CCL2) and C-X-C motif chemokine ligand 1 (CXCL1)], were decreased both in mRNA and protein levels by H2 inhalation in LPS-induced placentas to rescue them from BPD. Correlation analysis displayed a positive association of TLR4-mediated signaling pathway both proinflammatory cytokines and chemokines in placenta. CONCLUSION: H2 inhalation ameliorates LPS-induced BPD by inhibiting excessive inflammatory cytokines and chemokines via the TLR4-NFκB-IL6/NLRP3 signaling pathway in placenta and may be a potential therapeutic strategy for BPD.

The Molecular Biological Mechanism of Hydrogen Therapy and Its Application in Spinal Cord Injury.

Hydrogen, which is a novel biomedical molecule, is currently the subject of extensive research involving animal experiments and in vitro cell experiments, and it is gradually being applied in clinical settings. Hydrogen has been proven to possess anti-inflammatory, selective antioxidant, and antiapoptotic effects, thus exhibiting considerable protective effects in various diseases. In recent years, several studies have provided preliminary evidence for the protective effects of hydrogen on spinal cord injury (SCI). This paper provides a comprehensive review of the potential molecular biology mechanisms of hydrogen therapy and its application in treating SCI, with an aim to better explore the medical value of hydrogen and provide new avenues for the adjuvant treatment of SCI.

Potential role of molecular hydrogen therapy on oxidative stress and redox signaling in chronic kidney disease.

Oxidative stress plays a key role in chronic kidney disease (CKD) development and progression, inducing kidney cell damage, inflammation, and fibrosis. However, effective therapeutic interventions to slow down CKD advancement are currently lacking. The multifaceted pharmacological effects of molecular hydrogen (H2) have made it a promising therapeutic avenue. H2 is capable of capturing harmful •OH and ONOO- while maintaining the crucial reactive oxygen species (ROS) involved in cellular signaling. The NRF2-KEAP1 system, which manages cell redox balance, could be used to treat CKD. H2 activates this pathway, fortifying antioxidant defenses and scavenging ROS to counteract oxidative stress. H2 can improve NRF2 signaling by using the Wnt/ß-catenin pathway and indirectly activate NRF2-KEAP1 in mitochondria. Additionally, H2 modulates NF-κB activity by regulating cellular redox status, inhibiting MAPK pathways, and maintaining Trx levels. Treatment with H2 also attenuates HIF signaling by neutralizing ROS while indirectly bolstering HIF-1α function. Furthermore, H2 affects FOXO factors and enhances the activity of antioxidant enzymes. Despite the encouraging results of bench studies, clinical trials are still limited and require further investigation. The focus of this review is on hydrogen's role in treating renal diseases, with a specific focus on oxidative stress and redox signaling regulation, and it discusses its potential clinical applications.

Recent advances in the application of gasotransmitters in spinal cord injury.

Spinal Cord Injury (SCI) is a condition characterized by complete or incomplete motor and sensory impairment, as well as dysfunction of the autonomic nervous system, caused by factors such as trauma, tumors, or inflammation. Current treatment methods primarily include traditional approaches like spinal canal decompression and internal fixation surgery, steroid pulse therapy, as well as newer techniques such as stem cell transplantation and brain-spinal cord interfaces. However, the above methods have limited efficacy in promoting axonal and neuronal regeneration. The challenge in medical research today lies in promoting spinal cord neuron regeneration and regulating the disrupted microenvironment of the spinal cord. Studies have shown that gas molecular therapy is increasingly used in medical research, with gasotransmitters such as hydrogen sulfide, nitric oxide, carbon monoxide, oxygen, and hydrogen exhibiting neuroprotective effects in central nervous system diseases. The gas molecular protect against neuronal death and reshape the microenvironment of spinal cord injuries by regulating oxidative, inflammatory and apoptotic processes. At present, gas therapy mainly relies on inhalation for systemic administration, which cannot effectively enrich and release gas in the spinal cord injury area, making it difficult to achieve the expected effects. With the rapid development of nanotechnology, the use of nanocarriers to achieve targeted enrichment and precise control release of gas at Sites of injury has become one of the emerging research directions in SCI. It has shown promising therapeutic effects in preclinical studies and is expected to bring new hope and opportunities for the treatment of SCI. In this review, we will briefly outline the therapeutic effects and research progress of gasotransmitters and nanogas in the treatment of SCI.

The role of hydrogen in the prevention and treatment of coronary atherosclerotic heart disease.

Coronary atherosclerotic heart disease (CHD) is a primary cardiovascular disease caused by atherosclerosis (AS), which is characterized by chronic inflammation and lipid oxidative deposition. Molecular hydrogen (H2) is an effective anti-inflammatory agent and has potential to ameliorate glycolipid metabolism disorders, which is believed to exert beneficial effects on the prevention and treatment of CHD. It is suggested that H2 reduces inflammation in CHD by regulating multiple pathways, including NF-κB inflammatory pathway, pyroptosis, mitophagy, endoplasmic reticulum (ER) stress, and Nrf2 antioxidant pathway. Additionally, H2 may improve glycolipid metabolism by mediation of PI3K and AMPK signalling pathways, contributing to inhibition of the occurrence and development of CHD. This review elaborates pathogenesis of CHD and evaluates the role of H2 in CHD. Moreover, possible molecular mechanisms have been discussed and speculated, aiming to provide more strategies and directions for subsequent studies of H2 in CHD.

Hydrogen-rich solution alleviates acute radiation pneumonitis by regulating oxidative stress and macrophages polarization.

This study was aimed to investigate the effect of hydrogen-rich solution (HRS) on acute radiation pneumonitis (ARP) in rats. The ARP model was induced by X-ray irradiation. Histopathological changes were assessed using HE and Masson stains. Inflammatory cytokines were detected by ELISA. Immunohistochemistry and flow cytometry were performed to quantify macrophage (CD68) levels and the M2/M1 ratio. Western blot analysis, RT-qPCR, ELISA and flow cytometry were used to evaluate mitochondrial oxidative stress injury indicators. Immunofluorescence double staining was performed to colocalize CD68/LC3B and p-AMPK-α/CD68. The relative expression of proteins associated with autophagy activation and the adenosine 5'-monophosphate-activated protein kinase/mammalian target of rapamycin/Unc-51-like kinase 1 (AMPK/mTOR/ULK1) signaling pathway were detected by western blotting. ARP decreased body weight, increased the lung coefficient, collagen deposition and macrophage infiltration and promoted M1 polarization in rats. After HRS treatment, pathological damage was alleviated, and M1 polarization was inhibited. Furthermore, HRS treatment reversed the ARP-induced high levels of mitochondrial oxidative stress injury and autophagy inhibition. Importantly, the phosphorylation of AMPK-α was inhibited, the phosphorylation of mTOR and ULK1 was activated in ARP rats and this effect was reversed by HRS treatment. HRS inhibited M1 polarization and alleviated oxidative stress to activate autophagy in ARP rats by regulating the AMPK/mTOR/ULK1 signaling pathway.

Combined use of hydrogen-rich water and enzyme-digested edible bird's nest improves PMA/LPS-impaired wound healing in human inflammatory gingival tissue equivalents.

Gingival wound healing plays a critical role in maintaining oral health. However, this process can be delayed by oxidative stress and excessive inflammatory responses. In this study, we established a human inflammatory gingival tissue equivalent (iGTE) to investigate the inhibitory effects of hydrogen-rich water (HW), enzyme-digested edible bird's nest (EBND) and sialic acid (SA) on PMA (an inducer of oxidative free radicals)- and LPS (an inflammatory stimulus)-impaired wound healing. The iGTE was constructed by human gingival fibroblasts (hGFs), keratinocytes and macrophages under three-dimensional conditions. Wounds in the iGTE and hGF/keratinocyte monolayers were created by mechanical injury. Tissues and cells were pretreated with HW, EBND, and SA, and then exposed to the inflammatory and oxidative environment induced by PMA (10 ng/mL) and LPS (250 ng/mL). The inflammatory cytokines IL-6 and IL-8 were quantitatively analyzed by ELISA. Histopathological image analysis was performed by HE and immunofluorescence staining. In the iGTE, PMA/LPS significantly reduced the epithelial thickness while causing a decrease in K8/18, E-cadherin, laminin and elastin expression and an increase in COX-2 expression along with ulcer-like lesions. In mechanically scratched hGFs and keratinocyte monolayers, PMA/LPS significantly impaired wound healing, and promoted the secretion of IL-6 and IL-8. Pretreatment of HW, EBND, and SA significantly suppressed PMA/LPS-induced wound healing delay and inflammatory responses in cell monolayers, as well as in the iGTE. Remarkably, the combined use of HW and EBND exhibited particularly robust results. Combined use of HW and EBND may be applied for the prevention and treatment of wound healing delay.