Beneficial effects of hydrogen-rich saline on early burn-wound progression in rats

Mucoadhesive Chitosan Composite Sponge as a Carrier for β-Sitosterol Cubosomes for Thermal Burn Treatment

Our study aimed to explore the potential of using nanostructured lipid carriers (NLCs) to enhance the topical administration of β-sitosterol, a bioactive that is poorly soluble in water. Here, we have taken advantage of the unique characteristics that cubosomes have to provide as a drug delivery system. These characteristics include a large surface area, thermal stability, and the capacity to encapsulate molecules that are hydrophobic, amphiphilic, and hydrophilic. The cubosomal formulation was optimized by building a central composite design. The optimum dispersion exhibited a particle size of 88.3 nm, a zeta potential of -43, a polydispersity index of 0.358, and drug entrapment of 95.6%. It was composed of 15% w/w oleic acid and 5% w/w pluronic F127. The optimized cubosome dispersion was incorporated into a sponge formulation. The optimized cubosome sponge achieved a higher drug release compared with the cubosome dispersion. The SEM micrograph of the selected sponge showed that it has an interwoven irregular fibrous lamellar structure with low density and high porosity. The in-vivo data revealed that topical application of the β-sitosterol cubosomal sponge showed significant higher wound closure percentage relative to the β-sitosterol product (Mebo)®.

Gases and gas-releasing materials for the treatment of chronic diabetic wounds

Chronic non-healing wounds are a common consequence of skin ulceration in diabetic patients, with severe cases such as diabetic foot even leading to amputations. The interplay between pathological factors like hypoxia-ischemia, chronic inflammation, bacterial infection, impaired angiogenesis, and accumulation of advanced glycosylation end products (AGEs), resulting from the dysregulation of the immune microenvironment caused by hyperglycemia, establishes an unending cycle that hampers wound healing. However, there remains a dearth of sufficient and effective approaches to break this vicious cycle within the complex immune microenvironment. Consequently, numerous scholars have directed their research efforts towards addressing chronic diabetic wound repair. In recent years, gases including Oxygen (O2), Nitric oxide (NO), Hydrogen (H2), Hydrogen sulfide (H2S), Ozone (O3), Carbon monoxide (CO) and Nitrous oxide (N2O), along with gas-releasing materials associated with them have emerged as promising therapeutic solutions due to their ability to regulate angiogenesis, intracellular oxygenation levels, exhibit antibacterial and anti-inflammatory effects while effectively minimizing drug residue-induced damage and circumventing drug resistance issues. In this review, we discuss the latest advances in the mechanisms of action and treatment of these gases and related gas-releasing materials in diabetic wound repair. We hope that this review can provide different ideas for the future design and application of gas therapy for chronic diabetic wounds.

A bioelectronic device for electric field treatment of wounds reduces inflammation in an in vivo mouse model

Electrical signaling plays a crucial role in the cellular response to tissue injury in wound healing and an external electric field (EF) may expedite the healing process. Here, we have developed a standalone, wearable, and programmable electronic device to administer a well-controlled exogenous EF, aiming to accelerate wound healing in an in vivo mouse model to provide pre-clinical evidence. We monitored the healing process by assessing the re-epithelization rate and the ratio of M1/M2 macrophage phenotypes through histology staining. Following three days of treatment, the M1/M2 macrophage ratio decreased by 30.6% and the re-epithelization in the EF-treated wounds trended towards a non-statically significant 24.2% increase compared to the control. These findings provide point towards the effectiveness of the device in shortening the inflammatory phase by promoting reparative macrophages over inflammatory macrophages, and in speeding up re-epithelialization. Our wearable device supports the rationale for the application of programmed EFs for wound management in vivo and provides an exciting basis for further development of our technology based on the modulation of macrophages and inflammation to better wound healing.

HYDROGEN PREVENTS LIPOPOLYSACCHARIDE-INDUCED PULMONARY MICROVASCULAR ENDOTHELIAL CELL INJURY BY INHIBITING STORE-OPERATED Ca 2+ ENTRY REGULATED BY STIM1/ORAI1

ABSTRACT

Background: Sepsis is a type of life-threatening organ dysfunction that is caused by a dysregulated host response to infection. The lung is the most vulnerable target organ under septic conditions. Pulmonary microvascular endothelial cells (PMVECs) play a critical role in acute lung injury (ALI) caused by severe sepsis. The impairment of PMVECs during sepsis is a complex regulatory process involving multiple mechanisms, in which the imbalance of calcium (Ca 2+ ) homeostasis of endothelial cells is a key factor in its functional impairment. Our preliminary results indicated that hydrogen gas (H 2 ) treatment significantly alleviates lung injury in sepsis, protects PMVECs from hyperpermeability, and decreases the expression of plasma membrane stromal interaction molecule 1 (STIM1), but the underlying mechanism by which H 2 maintains Ca 2+ homeostasis in endothelial cells in septic models remains unclear. Thus, the purpose of the present study was to investigate the molecular mechanism of STIM1 and Ca 2+ release-activated Ca 2+ channel protein1 (Orai1) regulation by H 2 treatment and explore the effect of H 2 treatment on Ca 2+ homeostasis in lipopolysaccharide (LPS)-induced PMVECs and LPS-challenged mice. Methods: We observed the role of H 2 on LPS-induced ALI of mice in vivo . The lung wet/dry weight ratio, total protein in the bronchoalveolar lavage fluid, and Evans blue dye assay were used to evaluate the pulmonary endothelial barrier damage of LPS-challenged mice. The expression of STIM1 and Orai1 was also detected using epifluorescence microscopy. Moreover, we also investigated the role of H 2 -rich medium in regulating PMVECs under LPS treatment, which induced injury similar to sepsis in vitro . The expression of STIM1 and Orai1 as well as the Ca 2+ concentration in PMVECs was examined. Results:In vivo , we found that H 2 alleviated ALI of mice through decreasing lung wet/dry weight ratio, total protein in the bronchoalveolar lavage fluid and permeability of lung. In addition, H 2 also decreased the expression of STIM1 and Orai1 in pulmonary microvascular endothelium. In vitro , LPS treatment increased the expression levels of STIM1 and Orai1 in PMVECs, while H 2 reversed these changes. Furthermore, H 2 ameliorated Ca 2+ influx under sepsis-mimicking conditions. Treatment with the sarco/endoplasmic reticulum Ca 2+ adenosine triphosphatase inhibitor, thapsigargin, resulted in a significant reduction in cell viability as well as a reduction in the expression of junctional proteins, including vascular endothelial-cadherin and occludin. Treatment with the store-operated Ca 2+ entry inhibitor, YM-58483 (BTP2), increased the cell viability and expression of junctional proteins. Conclusions: The present study suggested that H 2 treatment alleviates LPS-induced PMVEC dysfunction by inhibiting store-operated Ca 2+ entry mediated by STIM1 and Orai1 in vitro and in vivo .

Kinetics of Inflammatory Mediators in the Immune Response to Burn Injury: Systematic Review and Meta-Analysis of Animal Studies

Burns are often accompanied by a dysfunctional immune response, which can lead to systemic inflammation, shock, and excessive scarring. The objective of this study was to provide insight into inflammatory pathways associated with burn-related complications. Because detailed information on the various inflammatory mediators is scattered over individual studies, we systematically reviewed animal experimental data for all reported inflammatory mediators. Meta-analyses of 352 studies revealed a strong increase in cytokines, chemokines, and growth factors, particularly 19 mediators in blood and 12 in burn tissue. Temporal kinetics showed long-lasting surges of proinflammatory cytokines in blood and burn tissue. Significant time-dependent effects were seen for IL-1β, IL-6, TGF-β1, and CCL2. The response of anti-inflammatory mediators was limited. Burn technique had a profound impact on systemic response levels. Large burn size and scalds further increased systemic, but not local inflammation. Animal characteristics greatly affected inflammation, for example, IL-1β, IL-6, and TNF-α levels were highest in young, male rats. Time-dependent effects and dissimilarities in response demonstrate the importance of appropriate study design. Collectively, this review presents a general overview of the burn-induced immune response exposing inflammatory pathways that could be targeted through immunotherapy for burn patients and provides guidance for experimental set-ups to advance burn research.

Hydrogen Attenuates Inflammation by Inducing Early M2 Macrophage Polarization in Skin Wound Healing

The heterogeneous and highly plastic cell populations of macrophages are important mediators of cellular responses during all stages of wound healing, especially in the inflammatory stage. Molecular hydrogen (H₂), which has potent antioxidant and anti-inflammatory effects, has been shown to promote M2 polarization in injury and disease. However, more in vivo time series studies of the role of M1-to-M2 polarization in wound healing are needed. In the current study, we performed time series experiments on a dorsal full-thickness skin defect mouse model in the inflammatory stage to examine the effects of H₂ inhalation. Our results revealed that H₂ could promote very early M1-to-M2 polarization (on days 2-3 post wounding, 2-3 days earlier than in conventional wound healing), without disturbing the functions of the M1 phenotype. Time series analysis of the transcriptome, blood cell counts, and multiple cytokines further indicated that peripheral blood monocytes were a source of H₂-induced M2 macrophages and that the functions of H₂ in macrophage polarization were not only dependent on its antioxidant effects. Therefore, we believe that H₂ could reduce inflammation in wound care by shifting early macrophage polarization in clinical settings.

Molecular hydrogen promotes wound healing by inducing early epidermal stem cell proliferation and extracellular matrix deposition

BACKGROUND

Despite progress in developing wound care strategies, there is currently no treatment that promotes the self-tissue repair capabilities. H₂ has been shown to effectively protect cells and tissues from oxidative and inflammatory damage. While comprehensive effects and how H₂ functions in wound healing remains unknown, especially for the link between H₂ and extracellular matrix (ECM) deposition and epidermal stem cells (EpSCs) activation.

METHODS

Here, we established a cutaneous aseptic wound model and applied a high concentration of H₂ (66% H₂) in a treatment chamber. Molecular mechanisms and the effects of healing were evaluated by gene functional enrichment analysis, digital spatial profiler analysis, blood perfusion/oxygen detection assay, in vitro tube formation assay, enzyme-linked immunosorbent assay, immunofluorescent staining, non-targeted metabonomic analysis, flow cytometry, transmission electron microscope, and live-cell imaging.

RESULTS

We revealed that a high concentration of H₂ (66% H₂) greatly increased the healing rate (3 times higher than the control group) on day 11 post-wounding. The effect was not dependent on O₂ or anti-reactive oxygen species functions. Histological and cellular experiments proved the fast re-epithelialization in the H₂ group. ECM components early (3 days post-wounding) deposition were found in the H₂ group of the proximal wound, especially for the dermal col-I, epidermal col-III, and dermis-epidermis-junction col-XVII. H₂ accelerated early autologous EpSCs proliferation (1-2 days in advance) and then differentiation into myoepithelial cells. These epidermal myoepithelial cells could further contribute to ECM deposition. Other beneficial outcomes include sustained moist healing, greater vascularization, less T-helper-1 and T-helper-17 cell-related systemic inflammation, and better tissue remodelling.

CONCLUSION

We have discovered a novel pattern of wound healing induced by molecular hydrogen treatment. This is the first time to reveal the direct link between H₂ and ECM deposition and EpSCs activation. These H₂-induced multiple advantages in healing may be related to the enhancement of cell viability in various cells and the maintenance of mitochondrial functions at a basic level in the biological processes of life.

Two-Dimensional Mg2 Si Nanosheet-Enabled Sustained Hydrogen Generation for Improved Repair and Regeneration of Deeply Burned Skin

Molecular hydrogen holds a high potential for wound healing owing to its anti-inflammatory effect and high biosafety, but commonly used hydrogen administration routes hardly achieve the sustained supply of high-dosage hydrogen, limiting hydrogen therapy efficacy. Here, two-dimensional Mg₂ Si nanosheet (MSN) is exploited as a super-persistent hydrogen-releasing nanomaterial with high biocompatibility, and the incorporation of MSN into the chitosan/hyaluronic acid hydrogel (MSN@CS/HA) is developed as a dressing to repair deeply burned skin. The MSN@CS/HA hydrogel dressing can continuously generate hydrogen molecules for about 1 week in the physiological conditions in support of local, long-term, and plentiful hydrogen supply and remarkably promotes the healing and regeneration of deep second-degree and third-degree burn wounds without visible scar and toxic side effect. Mechanistically, a sustained supply of hydrogen molecules induces anti-inflammatory M2 macrophage polarization in time by enhancing CCL2 (chemokine C-C motif ligand 2) expression to promote angiogenesis and reduce fibrosis and also enhances the proliferation and migration capability of skin cells directly and indirectly by locally scavenging overexpressed reactive oxygen species, synergistically favoring wound repair. The proposed synthesis method, therapeutic strategy, and mechanisms will open a window for synthesizing a variety of MSene nanomaterials and developing their various proangiogenesis applications besides wound healing.

Metformin Improves Burn Wound Healing by Modulating Microenvironmental Fibroblasts and Macrophages

Metformin, a biguanide, exerts different functions through various signaling pathways. In order to investigate the function and mechanism of metformin in burn wounds, we established burn rat models, subcutaneously injected metformin to treat the wounds, and observed the morphologies and the expression of collagen I, collagen III, fibronectin, and pro-inflammatory markers. In vitro experiments were performed to investigate the effects of metformin on the proliferation, migration, and collagen I synthesis of the mouse embryonic fibroblast (NIH 3T3) cell line and on the proliferation, apoptosis, and immune response of the mouse mononuclear macrophage (RAW 264.7) cell line. Finally, we studied the regulatory effects of metformin on a co-culture of RAW 264.7/NIH 3T3 cells. We found that 100 mM of metformin reduced dermal thickness, collagen I deposition, and mRNA expression of IL1β and CCL2 in rat burn wounds. In vitro experiments revealed that metformin inhibited the proliferation of NIH 3T3 and RAW 264.7 cells. Metformin attenuated NIH 3T3 cell migration via the AMPK/mTOR pathway and attenuated collagen I synthesis through the TGFβ1/Smad3 pathway. Metformin inhibited the apoptosis of RAW 264.7 cells induced by 10 μg/mL LPS. Metformin downregulated the mRNA expression of IL1β and CCL2 in RAW 264.7 cells under 1 μg/mL LPS induction by inhibiting NF-κB p65 phosphorylation. In a RAW 264.7/NIH 3T3 co-culture, metformin attenuated collagen I synthesis in NIH 3T3 cells by inhibiting RAW 264.7 paracrine secretion of TGF-β1. This provides new evidence related to the development of metformin for potentially improving burn wound healing.

Effect of hydrogen intervention on refractory wounds after radiotherapy: A case report

BACKGROUND

Patients with keloids who receive radiotherapy (RT) after surgery can develop refractory wounds that cannot be healed by the patient's own repair system. Such chronic wounds are uneven and complex due to persistent abscess and ulceration. Without external intervention, they can easily result in local tissue necrosis or, in severe cases, large area tissue resection, amputation, and even death.

CASE SUMMARY

This article describes the use of hydrogen to treat a 42-year-old female patient with a chronic wound on her left shoulder. The patient had a skin graft that involved implanting a dilator under the skin of her left shoulder, and then transferring excess skin from her shoulder onto scar tissue on her chest. The skin grafting was followed by two rounds of RT, after which the shoulder wound had difficulty healing. For six months, the patient was treated with 2 h of hydrogen inhalation (HI) therapy per day, in addition to application of sterile gauze on the wound and periodic debridement. We also performed one deep, large, sharp debridement to enlarge the wound area. The wound healed completely within 6 mo of beginning the HI treatment.

CONCLUSION

After HI therapy, the patient showed superior progress in reepithelialization and wound repair, with eventual wound closure in 6 mo, in comparison with the previous failures of hyperbaric oxygen and recombinant bovine basic fibroblast growth factor therapies. Our work showed that HI therapy could be a new strategy for wound healing that is cleaner, more convenient, and less expensive than other therapies, as well as easily accessible for further application in clinical wound care.

Burn-Induced Local and Systemic Immune Response: Systematic Review and Meta-Analysis of Animal Studies

As burn injuries are often followed by a derailed immune response and excessive inflammation, a thorough understanding of the occurring reactions is key to prevent secondary complications. This systematic review, that includes 247 animal studies, shows the post-burn response of 14 different immune cell types involved in immediate and long-term effects, in both wound tissue and circulation. Peripheral blood neutrophil and monocyte numbers increased directly after burns, whereas thrombocyte numbers increased near the end of the first week. Lymphocyte numbers, however, were decreased for at least two weeks. In burn wound tissue, neutrophil and macrophage numbers accumulated during the first three weeks. Burns also altered cellular functions as we found increased migratory potential of leukocytes, impaired antibacterial activity of neutrophils and enhanced inflammatory mediator production by macrophages. Neutrophil surges were positively associated with burn size and were highest in rats. Altogether, this comprehensive overview of the temporal immune cell dynamics shows that unlike normal wound healing, burn injury induces a long-lasting inflammatory response. It provides a fundamental research basis to improve experimental set-ups, burn care and outcome.

Protective Effects of Hydrogen-Rich Saline on Experimental Intestinal Volvulus in Rats

BACKGROUND

Intestinal volvulus can cause morbidity and mortality. Surgical reduction, on the other hand, could result in ischemia-reperfusion (I/R) injury. Hydrogen rich saline solution (HRSS neutralizes free radicals in the body. This study aimed to investigate the effects of HRSS in I/R injury in experimental intestinal volvulus in rats.

METHODS

Thirty rats were randomly allocated into 5 groups. All procedures were done under general anesthesia and sterile conditions in each animal. Five ml/kg of saline and HRSS were administered intraperitoneally (ip) in Sham (Group 1) and HRSS (Group 2) groups, respectively. Groups 3, 4, and 5 constituted the study groups in which volvulus was created in a 5-cm- long ileal segment 2 cm proximal to the ileocecal valve. After 2 hours the volvuli were reduced and following 2 hours of reperfusion, these segments were removed. In volvulus-I/R group (Group 3) no additional procedure was done. HRSS was administered shortly before reperfusion (reduction of the volvulus) in Treatment I (Group 4) and 1 h before experimental volvulus in Treatment II (Group 5) groups. Blood and intestinal tissue samples were obtained from all rats at the 4th hour. Both tissue and blood total oxidant (TOS) and antioxidant status (TAS) levels were determined and tissue histomorphologies were studied. Oxidative stress indices (TOS ÷ TAS) (OSI) were calculated.

RESULTS

Tissue TOS and OSI levels and histomorphological injury scores were statistically lower in treatment groups than I/R group, whereas blood TOS and OSI levels were similar between the groups.

CONCLUSIONS

This study provides biochemical and histomorphological evidence that HRSS prevents intestinal damage in I/R injury caused by volvulus.

Local Treatment of Hydrogen-Rich Saline Promotes Wound Healing In Vivo by Inhibiting Oxidative Stress via Nrf-2/HO-1 Pathway

Wound healing is a complex dynamic process involving a large number of biological events. Excessive oxidative stress is a key factor delaying wound healing. Hydrogen is an antioxidant, anti-inflammatory, and antiapoptotic medical gas with safety, effectiveness, and penetrability. However, the effects of local treatment of hydrogen on wound healing and its potential mechanisms remain unclear. In this study, Kunming (KM) mice were used to set up a wound model. All the mice were randomly divided into the control, the local treatment with saline group, the local treatment with the hydrogen-rich saline group, and the intraperitoneal injection of the hydrogen-rich saline group. To evaluate the impact of hydrogen-rich saline on wound healing, we assessed the wound healing rate, wound closure time, histomorphology, oxidative stress indicators, inflammatory cytokines, the apoptosis index, and the expression of the nuclear factor-erythroid-related factor 2(Nrf-2). Furthermore, the immortalized nontumorigenic human epidermal (HaCaT) cells were chosen to investigate the therapeutic effects of hydrogen-rich medium on oxidative stress and its underlying mechanisms. The results showed that local treatment of hydrogen-rich saline shortened wound closure time and reduced the level of proinflammatory cytokines and lipid peroxidation. Meanwhile, it decreased the cell apoptosis index and increased the Nrf-2 expression. Besides, hydrogen-rich medium relieved the oxidative stress via the activation of the Nrf-2/heme oxygenase-1 (HO-1) pathway. In conclusion, local treatment of hydrogen-rich saline exhibits the healing-promoting function through antioxidant, anti-inflammatory, and antiapoptotic effects. Hydrogen relieves the oxidative stress in the wound microenvironment via Nrf-2/HO-1 signaling pathway. This study may offer a new strategy to promote wound healing and a new perspective to illustrate the mechanism of wound healing.

The effects of inhaling hydrogen gas on macrophage polarization, fibrosis, and lung function in mice with bleomycin-induced lung injury

Background

Acute respiratory distress syndrome, which is caused by acute lung injury, is a destructive respiratory disorder caused by a systemic inflammatory response. Persistent inflammation results in irreversible alveolar fibrosis. Because hydrogen gas possesses anti-inflammatory properties, we hypothesized that daily repeated inhalation of hydrogen gas could suppress persistent lung inflammation by inducing functional changes in macrophages, and consequently inhibit lung fibrosis during late-phase lung injury.

Methods

To test this hypothesis, lung injury was induced in mice by intratracheal administration of bleomycin (1.0 mg/kg). Mice were exposed to control gas (air) or hydrogen (3.2% in air) for 6 h every day for 7 or 21 days. Respiratory physiology, tissue pathology, markers of inflammation, and macrophage phenotypes were examined.

Results

Mice with bleomycin-induced lung injury that received daily hydrogen therapy for 21 days (BH group) exhibited higher static compliance (0.056 mL/cmH₂O, 95% CI 0.047–0.064) than mice with bleomycin-induced lung injury exposed only to air (BA group; 0.042 mL/cmH₂O, 95% CI 0.031–0.053, p = 0.02) and lower static elastance (BH 18.8 cmH₂O/mL, [95% CI 15.4–22.2] vs. BA 26.7 cmH₂O/mL [95% CI 19.6–33.8], p = 0.02). When the mRNA levels of pro-inflammatory cytokines were examined 7 days after bleomycin administration, interleukin (IL)-6, IL-4 and IL-13 were significantly lower in the BH group than in the BA group. There were significantly fewer M2-biased macrophages in the alveolar interstitium of the BH group than in the BA group (3.1% [95% CI 1.6–4.5%] vs. 1.1% [95% CI 0.3–1.8%], p = 0.008).

Conclusions

The results suggest that hydrogen inhalation inhibits the deterioration of respiratory physiological function and alveolar fibrosis in this model of lung injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01712-2.

Metal chelation attenuates oxidative stress, inflammation, and vertical burn progression in a porcine brass comb burn model

Oxidative stress and inflammation may mediate cellular damage and tissue destruction as the burn wound continues to progress after the abatement of the initial insult. Since iron and calcium ions play key roles in oxidative stress, this study tested whether topical application of a metal chelator proprietary lotion (Livionex Formulation (LF) lotion), that contains disodium EDTA as a metal chelator and methyl sulfonyl methane (MSM) as a permeability enhancer, would prevent progression or reduce burn wound severity in a porcine model. We have reported earlier that in a rat burn model, LF lotion reduces thermal injury progression. Here, we used the porcine brass comb burn model that closely mimics the human condition for contact burns and applied LF lotion every 8 h starting 15 min after the injury. We found that LF lotion reduces the depth of cell death as assessed by TUNEL staining and blood vessel blockage in the treated burn sites and interspaces. The protein expression of pro-inflammatory markers IL-6, TNF-a, and TNFα Converting Enzyme (TACE), and lipid aldehyde production (protein-HNE) was reduced with LF treatment. LF lotion reversed the burn-induced decrease in the aldehyde dehydrogenase (ALDH-1) expression in the burn sites and interspaces. These data show that a topically applied EDTA-containing lotion protects both vertical and horizontal burn progression when applied after thermal injury. Curbing burn wound conversion and halting the progression of second partial burn to third-degree full-thickness burn remains challenging when it comes to burn treatment strategies during the acute phase. Burn wound conversion can be reduced with targeted treatments to attenuate the oxidative and inflammatory response in the immediate aftermath of the injury. Our studies suggest that LF lotion could be such a targeted treatment.

Role of Molecular Hydrogen in Skin Diseases and its Impact in Beauty

In today's society, healthy skin and a beautiful appearance are considered the foundation of general well-being. The skin is the largest organ of the body and plays an important role in protecting it against various hazards such as environmental, physical, chemical, and biological hazards. These factors include mediators that lead to oxidation reactions that produce reactive oxygen/nitrogen species and additional oxidants in the skin cells. An increase in oxidants beyond the antioxidant capacity of its defense system causes oxidative stress and chronic inflammation in the body. This response can cause further disruption of collagen fibers and hinder the functioning of skin cells that may result in the development of various skin diseases including psoriasis, atopic dermatitis, and aging. In this review, we summarized the present information related to the role of oxidative stress in the pathogenesis of dermatological disorders, and its impact on physical beauty and the daily lives of patients. We also discussed how molecular hydrogen exhibits a therapeutic effect against skin diseases via its effects on oxidative stress. Furthermore, findings from this summary review indicate that molecular hydrogen might be an effective treatment modality for the prevention and treatment of skin-related illnesses.

ASMq protects against early burn wound progression in rats by alleviating oxidative stress and secondary mitochondria‑associated apoptosis via the Erk/p90RSK/Bad pathway

Burn wounds present an evolutionary progression, in which the initial wound tissue deepens and expands following thermal injury. Progressive tissue damage in the zone of stasis may worsen burn injury, which is associated with oxidative stress and secondary apoptosis, and worsen the prognosis of patients with burn wounds. The mitochondrial apoptotic pathway is involved in receiving oxidative signals and regulating tissue apoptosis. Previously, Abnormal Savda Munziq (ASMq), a natural compound of traditional Uyghur Medicine, which includes ten types of herb, has been reported to exhibit a number of effects, including anti-inflammatory, antioxidative and anti-apoptotic activities. The present study demonstrated that ASMq protected against early burn wound progression following thermal injury in rats; this effect may be mediated by its ability to attenuate oxidative stress-induced mitochondria-associated apoptosis. The present study may provide a novel therapeutic method to prevent early burn wound progression following burn injury.

Locally activated mitophagy contributes to a "built-in" protection against early burn-wound progression in rats

AIMS

Deep burn-wounds undergo a dynamic progression in the initial or periburn area after insults, and the zone of stasis is the crucial region suffering the deterioration, considered as salvageable. Few studies explored the role of mitochondria in this process. This study is to clarify a possible "built-in" protection of mitophagy.

MAIN METHODS

A classic "comb" scald rat model was established. Histological and blood-flow observation were processed based on hematoxylin-eosin staining and laser analysis. Oxidative and apoptotic status were analyzed by commercial kits. Transmission-electron microscope, immunofluorescence staining, and western blot were applied to detect the mitophagy in the zone of stasis and potential regulators. Adenovirus-based gene-silence contributed to determine the role of HIF-1α as a regulatory mediator.

KEY FINDINGS

We found that burn-caused typical ischemia and histological deterioration in the zone of stasis, in parallel with increases in oxidative stress and apoptosis. Mitochondrial damage was involved in the aforementioned changes. Furthermore, we detected mitophagy in burn-wounds, which was contradictory to the burn-wound conversion. HIF-1α expression was closely related to the level of mitophagy, while BNIP3 and PARKIN are involved downstream.

SIGNIFICANCE

We demonstrate that burn-induced mitochondrial impairment contributes to the mobilization of injurious mechanisms in the zone of stasis and that mitophagy provides a beneficial way to protect against burn-wound progression via the elimination of damaged mitochondria. Our findings offer insights into mitochondrial quality control in burn-wound progression and suggest the novel concept that HIF-1α may be a therapeutic target due to its possible regulation on BNIP3- or PARKIN-mediated mitophagy.

Modeling Burn Progression Using Comb Burns: The Impact of Thermal Contact Duration on Model Outcomes

BACKGROUND

Burn progression is a phenomenon that remains poorly characterized. The mechanisms of burn conversion are not completely understood, and consequently, both predictive diagnostic tools and interventions are limited. The rat comb burn model is a commonly used approach to study horizontal burn conversion. However, there is significant variability in how the model is performed. Skin contact duration, comb device heating method, comb heating duration, amount of pressure applied, the weight of the comb, and associated depth of burn are all variables that are heterogeneous in studies utilizing the model.

MATERIALS AND METHODS

Here, contact duration was examined to determine the impact the duration of burn delivery has on the conversion of interspaces in this model. Data from multiple experiments consisting of 10, 15, 20, 30, 40, and 45 s comb burns were compiled and assessed. Burns were made using combs heated in a 100°C dry bath and then monitored for 2 d. Interspace viability was assessed by digital and laser doppler imaging and biopsy procurement.

RESULTS

Laser Doppler Imaging and viable interspace measurements showed that as burn duration increased, the percentage of the viable interspace and interspace perfusion decreased. Additionally, a contact time of 30 s or greater was required to result in 100% interspace conversion.

CONCLUSIONS

These results demonstrate a need to better characterize and potentially standardize the rat comb burn model to reduce variation and maintain it as a valuable tool for controlled studies of the pathophysiology of burn wound progression.

The effects of hydrogen-rich saline solution on intestinal anastomosis performed after intestinal ischemia reperfusion injury

AIM

We investigated the effects of hydrogen-rich saline solution (HRSS) on intestinal anastomosis performed after intestinal ischemia reperfusion injury (IRI).

MATERIALS AND METHODS

Thirty Wistar albino female rats were randomly divided into five groups. Only laparotomy was performed in the Sham group. In the other four groups, an intestinal IRI was performed for 45 min by clamping the superior mesenteric artery. After intestinal IRI, anastomosis was performed by cutting the intestine from the proximal 15 cm of the ileocecal valve at the first and 24th hours. HRSS was given intraperitoneally 5 ml/kg before reperfusion and for four more days in the HRSS¹ and HRSS²⁴groups, while no treatment was given to the I/R¹ and I/R²⁴ groups. After 5 days, all groups underwent relaparotomy. The anastomotic bursting pressures were measured in all groups, except the Sham group. The tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), myeloperoxidase (MPO) and malondialdehyde (MDA) levels were measured in the tissues taken from the anastomosis line. The tissue sections were evaluated histopathologically and the apoptosis index was determined by applying the TUNEL method. The results were analyzed one-way analysis of variance (ANOVA) and Pearson's chi-squared test.

RESULTS

Although the MPO, MDA, IL-6 and TNF-α tissue values were not statistically significant among the groups, the degree of tissue damage and apoptosis levels were lower and the anastomotic bursting pressures values were higher in the HRSS¹ and HRSS²⁴ groups compared to the I/R¹ and I/R²⁴ groups.

CONCLUSION

HRSS is effective in reducing the intestinal damage caused by an IRI: HRSS has the potential to reduce the detrimental effects of intestinal anastomosis performed after an intestinal IRI.

Comprehensive perception of burn conversion: a literature review

Burn conversion is the conversion of stasis zone into both greater burn area and burn depth. It may hamper the patient's condition since morbidity and mortality are expected to be higher with the increase of burn size. To gain a comprehensive perception of burn conversion, this study aims to collect the latest updates regarding therapy, diagnosis, etiology and prognosis. A literature search was carried out on online databases, namely PubMed, SCOPUS and PROQUEST. The keywords "Burns AND (Conversion OR Progression OR Expansion)" were formulated. The inclusion and exclusion criteria were applied. Twenty-six articles were found, which were divided into diagnosis of burn conversion (11%), etiology of burn conversion (8%), prognosis of burn conversion (0%), and therapy of burn conversion (81%). All of the research was performed on animals. One of the best tools to diagnose burn conversion was the forwardlooking infrared (FLIR) imaging, having sensitivity up to 96% and specificity up to 100% to predict scar depth ≥3 mm. The main etiology was ischemia, reactive oxygen species and inflammation. Most of the research regarding therapy showed benefit in preventing burn conversion. However, no side effects were investigated and not all of the research was statistically significant. More research on burn conversion prognosis and treatment side effects should be performed. Further research involving trials in humans should be conducted, since animal and human trials may differ.

The effects of epidermal growth factor on early burn-wound progression in rats

After burns, protecting tissues by medicines in the zone of stasis reduces the width and depth of injury. This study's goal was to reduce burned tissue damage in the zone of stasis using epidermal growth factor (EGF). Forty-eight Wistar rats were separated into three groups. In all groups, the burn procedure was applied following the comb burn model. In Group 1, no postburn treatment was administered. In Group 2, physiological saline solution (0.3 cc) was injected intradermally and in Group 3, EGF (0.3 cc) was injected intradermally into stasis zone tissues after the burn procedure. Surviving tissue rates were 24.0% in Group 1, 25.3% in Group 2, and 70.2% in Group 3. The average numbers of cells stained with Nrf2, HO-1, and the number of apoptotic cells were 230, 150, and 17.5 in Group 1, 230, 145, and 15.0 in Group 2, and 370, 230, and 0 in Group 3, respectively. Values in Group 3 were found to be statistically significantly different than those of Groups 1 and 2; there was no difference between Groups 1 and 2. This study shows that EGF protects zone of stasis tissue from burn damage.

Prevention of Burn Wound Progression by Mesenchymal Stem Cell Transplantation: Deeper Insights Into Underlying Mechanisms

INTRODUCTION

Burns are dynamic wounds that may present a progressive expansion of necrosis into the initially viable zone of stasis. Therefore, salvage of this zone is a major subject of focus in burn research. The beneficial effects of mesenchymal stem cells (MSCs) on the survival of the zone of stasis have been previously documented. However, many gaps still exist in our knowledge regarding the underlying protective mechanisms. Hence, this study was designed to evaluate the pathophysiological basis of MSCs in the prevention of burn wound progression.

METHODS

Wistar rats received thermal trauma on the back according to the "comb burn" model. Animals were randomly divided into sham, control, and stem cell groups with sacrifice and analysis at 72 hours after the burn. The stasis zones were evaluated using histochemistry, immunohistochemistry, biochemistry, real-time polymerase chain reaction assay, and scintigraphy to evaluate the underlying mechanisms.

RESULTS

Gross evaluation of burn wounds revealed that vital tissue percentage of the zone of stasis was significantly higher in the stem cell group. Semiquantitative grading of the histopathologic findings showed that MSCs alleviated burn-induced histomorphological alterations in the zone of stasis. According to CC3a staining and expression analysis of Bax (B-cell leukemia 2-associated X) and Bcl-2 (B-cell leukemia 2) genes, MSCs attenuated increases in apoptosis postburn. In addition, these transplants showed an immunomodulatory effect that involves reduced neutrophilic infiltration, down-regulation of proinflammatory cytokines (tumor necrosis factor α, interleukin 1β [IL-1β], and IL-6), and up-regulation of the anti-inflammatory cytokine IL-10 in the zone of stasis. Burn-induced oxidative stress was significantly relieved with MSCs, as shown by increased levels of malondialdehyde, whereas the expression and activity of the antioxidant enzyme superoxide dismutase were increased. Finally, MSC-treated interspaces had enhanced vascular density with higher expression levels for vascular endothelial growth factor A, platelet-derived growth factor, fibroblast growth factor, and transforming growth factor β. Gamma camera images documented better tissue perfusion in animals treated with MSCs.

CONCLUSIONS

The protective effects of MSCs are mediated by the inhibition of apoptosis through immunomodulatory, antioxidative, and angiogenic actions.

Isothiocyanate from Moringa oleifera seeds mitigates hydrogen peroxide-induced cytotoxicity and preserved morphological features of human neuronal cells

Reactive oxygen species are well known for induction of oxidative stress conditions through oxidation of vital biomarkers leading to cellular death via apoptosis and other process, thereby causing devastative effects on the host organs. This effect is believed to be linked with pathological alterations seen in several neurodegenerative disease conditions. Many phytochemical compounds proved to have robust antioxidant activities that deterred cells against cytotoxic stress environment, thus protect apoptotic cell death. In view of that we studied the potential of glucomoringin-isothiocyanate (GMG-ITC) or moringin to mitigate the process that lead to neurodegeneration in various ways. Neuroprotective effect of GMG-ITC was performed on retinoic acid (RA) induced differentiated neuroblastoma cells (SHSY5Y) via cell viability assay, flow cytometry analysis and fluorescence microscopy by means of acridine orange and propidium iodide double staining, to evaluate the anti-apoptotic activity and morphology conservation ability of the compound. Additionally, neurite surface integrity and ultrastructural analysis were carried out by means of scanning and transmission electron microscopy to assess the orientation of surface and internal features of the treated neuronal cells. GMG-ITC pre-treated neuron cells showed significant resistance to H₂O₂-induced apoptotic cell death, revealing high level of protection by the compound. Increase of intracellular oxidative stress induced by H₂O₂ was mitigated by GMG-ITC. Thus, pre-treatment with the compound conferred significant protection to cytoskeleton and cytoplasmic inclusion coupled with conservation of surface morphological features and general integrity of neuronal cells. Therefore, the collective findings in the presence study indicated the potentials of GMG-ITC to protect the integrity of neuron cells against induced oxidative-stress related cytotoxic processes, the hallmark of neurodegenerative diseases.

[Protective effects of hydrogen-rich medium on lipopolysaccharides-induced injury in human periodontal ligament cells]

OBJECTIVE

In this study, lipopolysaccharides (LPS) was used to damage human periodontal ligament cells (hPDLCs) and consequently investigate the protective effects of hydrogen on reducing oxidative stress and cell apoptosis rate.

METHODS

hPDLCs were isolated, and then cultured with normal medium+1 μg·mL⁻¹ LPS or with hydrogen-rich medium+
1 μg·mL⁻¹ LPS. Cell proliferation activity was assessed using a cell counting kit-8 (CCK-8), and lactic dehydrogenase (LDH) release was also detected. The activities of superoxide dismutase (SOD) and catalase (CAT), and the level of malonaldehyde (MDA) in supernatants were also measured. Cell apoptosis was detected by flow cytometry at 24 h after LPS stimulation.

RESULTS

CCK-8 results showed that hydrogen could significantly improve hPDLCs growth and decrease cell apoptosis under LPS stimulation (P<0.05). However, no significant difference in LDH release was found between the two groups. The CAT levels significantly increased at 6 and 12 h in the hydrogen-rich medium as compared with the normal medium group (P<0.05, P<0.01, respectively). However, SOD levels were not significant different at each time point. At 6 h after LPS stimulation, the MDA levels in the cell supernatant of hydrogen-rich medium group were significantly reduced as compared with those in the normal medium group (P<0.05).

CONCLUSIONS

The hydrogen-rich medium can effectively improve hPDLCs proliferation activity and antioxidant capacity and reduce apoptosis and oxidative stress under LPS stimulation.

Hydrogen gas alleviates oxygen toxicity by reducing hydroxyl radical levels in PC12 cells

Hyperbaric oxygen (HBO) therapy through breathing oxygen at the pressure of above 1 atmosphere absolute (ATA) is useful for varieties of clinical conditions, especially hypoxic-ischemic diseases. Because of generation of reactive oxygen species (ROS), breathing oxygen gas at high pressures can cause oxygen toxicity in the central nervous system, leading to multiple neurological dysfunction, which limits the use of HBO therapy. Studies have shown that Hydrogen gas (H₂) can diminish oxidative stress and effectively reduce active ROS associated with diseases. However, the effect of H₂ on ROS generated from HBO therapy remains unclear. In this study, we investigated the effect of H₂ on ROS during HBO therapy using PC12 cells. PC12 cells cultured in medium were exposed to oxygen gas or mixed oxygen gas and H₂ at 1 ATA or 5 ATA. Cells viability and oxidation products and ROS were determined. The data showed that H₂ promoted the cell viability and inhibited the damage in the cell and mitochondria membrane, reduced the levels of lipid peroxidation and DNA oxidation, and selectively decreased the levels of •OH but not disturbing the levels of O₂^•-, H₂O₂, or NO• in PC12 cells during HBO therapy. These results indicated that H₂ effectively reduced •OH, protected cells against oxygen toxicity resulting from HBO therapy, and had no effect on other ROS. Our data supported that H₂ could be potentially used as an antioxidant during HBO therapy.

Hydrogen-rich saline attenuates isoflurane-induced caspase-3 activation and cognitive impairment via inhibition of isoflurane-induced oxidative stress, mitochondrial dysfunction, and reduction in ATP levels

OBJECTIVES

The inhaled general anesthetic isoflurane has been shown to induce caspase-3 activation in vitro and in vivo. The underlying mechanisms and functional consequences of this activity remain unclear. Isoflurane can induce caspase-3 activation by causing accumulation of reactive oxygen species (ROS), mitochondrial dysfunction, and reduction in adenosine triphosphate (ATP) levels. This study aimed to investigate the protective effect of hydrogen, a novel antioxidant, against isoflurane-induced caspase-3 activation and cognitive impairment.

METHODS

H4 human neuroglioma cells overexpressing human amyloid precursor protein were treated with saline or hydrogen-rich saline (HS, 300 μM), with or without 2% isoflurane, for 6 h or 3 h. Western blot analysis, fluorescence assays, and a mitochondrial swelling assay were used to evaluate caspase-3 activation, levels of ROS and ATP, and mitochondrial function. The effect of the interaction of isoflurane (1.4% for 2 h) and HS (5 mL/kg) on cognitive function in mice was also evaluated using a fear conditioning test.

RESULTS

We found that HS attenuated isoflurane-induced caspase-3 activation. Moreover, HS treatment mitigated isoflurane-induced ROS accumulation, opening of mitochondrial permeability transition pores, reduction in mitochondrial membrane potential, and reduction in cellular ATP levels. Finally, HS significantly alleviated isoflurane-induced cognitive impairment in mice.

CONCLUSIONS

Our results suggest that HS attenuates isoflurane-induced caspase-3 activation and cognitive impairment via inhibition of isoflurane-induced oxidative stress, mitochondrial dysfunction, and reduction in ATP levels. These findings warrant further research into the underlying mechanisms of this activity, and indicate that HS has the potential to attenuate anesthesia neurotoxicity.

Astaxanthin protects against early burn-wound progression in rats by attenuating oxidative stress-induced inflammation and mitochondria-related apoptosis

Burn-wound progression can occur in the initial or peri-burn area after a deep burn injury. The stasis zone has a higher risk of deterioration mediated by multiple factors but is also considered salvageable. Astaxanthin (ATX), which is extracted from some marine organisms, is a natural compound with a strong antioxidant effect that has been reported to attenuate organ injuries caused by traumatic injuries. Hence, we investigated the potential effects of ATX on preventing early burn-wound progression. A classic "comb" burn rat model was established in this study for histological and biological assessments, which revealed that ATX, particularly higher doses, alleviated histological deterioration in the stasis zone. Additionally, we observed dose-dependent improvements in oxidative stress and the release of inflammatory mediators after ATX treatment. Furthermore, ATX dose-dependently attenuated burn-induced apoptosis in the wound areas, and this effect was accompanied by increases in Akt and Bad phosphorylation and a downregulation of cytochrome C and caspase expression. In addition, the administration of Ly 294002 further verified the effect of ATX. In summary, we demonstrated that ATX protected against early burn-wound progression in a rat deep-burn model. This protection might be mediated by the attenuation of oxidative stress-induced inflammation and mitochondria-related apoptosis.

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.

Effects of hydrogen-rich saline on early acute kidney injury in severely burned rats by suppressing oxidative stress induced apoptosis and inflammation

Background

Early acute kidney injury (AKI) in severely burned patients predicts a high mortality that is multi-factorial. Hydrogen has been reported to alleviate organ injury via selective quenching of reactive oxygen species. This study investigated the potential protective effects of hydrogen against severe burn-induced early AKI in rats.

Methods

Severe burn were induced via immersing the shaved back of rats into a 100°C bath for 15 s. Fifty-six Sprague–Dawley rats were randomly divided into Sham, Burn + saline, and Burn + hydrogen-rich saline (HS) groups, and renal function and the apoptotic index were measured. Kidney histopathology and immunofluorescence staining, quantitative real-time PCR, ELISA and western blotting were performed on the sera or renal tissues of burned rats to explore the underlying effects and mechanisms at varying time points post burn.

Results

Renal function and tubular apoptosis were improved by HS treatment. In addition, the oxidation–reduction potential and malondialdehyde levels were markedly reduced with HS treatment, whereas endogenous antioxidant enzyme activities were significantly increased. HS also decreased the myeloperoxidase levels and influenced the release of inflammatory mediators in the sera and renal tissues of the burned rats. The regulatory effects of HS included the inhibition of p38, JNK, ERK and NF-κB activation, and an increase in Akt phosphorylation.

Conclusion

Hydrogen can attenuate severe burn-induced early AKI; the mechanisms of protection include the inhibition of oxidative stress induced apoptosis and inflammation, which may be mediated by regulation of the MAPKs, Akt and NF-κB signalling pathways.