Effects Of Hyperbaric Oxygen Research Articles

Hyperbaric oxygen therapy attenuates heatstroke-induced hippocampal injury by inhibiting microglial pyroptosis

Background: Central nervous system (CNS) injury is the most prominent feature of heatstroke and the hippocampus is prone to damage. However, the mechanisms underlying the heatstroke-induced hippocampal injury remain unclear. Hyperbaric oxygen (HBO) therapy prevents CNS injury in heatstroke mice. However, the underlying mechanisms of HBO in heatstroke-induced hippocampal injury remain unclear. This study aimed to elucidate the protective effects of HBO against hippocampal injury and its potential role in microglial pyroptosis in heatstroke rats.Methods: A rat heatstroke model and a heat stress model with a mouse microglial cell line (BV2) were, respectively, used to illustrate the effect of HBO on heat-induced microglial pyroptosis in vivo and in vitro. We used a combination of molecular and histological methods to assess microglial pyroptosis and neuroinflammation both in vivo and in vitro.Results: The results revealed that HBO improved heatstroke-induced survival outcomes, hippocampal injury, and neurological dysfunction in rats. In addition, HBO mitigates microglial pyroptosis and reduces the expression of pro-inflammatory cytokines in the hippocampus of heatstroke rats. In vitro experiments showed that HBO attenuated BV2 cell injury under heat stress. Furthermore, HBO prevented heat-induced pyroptosis of BV2 cells, and the expression of pro-inflammatory cytokines IL-18 and IL-1β was reduced. Mechanistically, HBO alleviates heatstroke-induced neuroinflammation and hippocampal injury by preventing microglial pyroptosis. Conclusions: In conclusion, HBO attenuates heatstroke-induced neuroinflammation and hippocampal injury by inhibiting microglial pyroptosis.

Hyperbaric Oxygen Attenuates Chronic Postsurgical Pain by Regulating the CD73/Adenosine/A1R Axis of the Spinal Cord in Rats

Chronic postsurgical pain (CPSP) affects postoperative rehabilitation and quality of life in patients, but its mechanisms are still poorly understood. Hyperbaric oxygen (HBO) attenuates neuropathic pain in animal and human studies, but its efficacy for CPSP treatment and its underlying mechanism have not been elucidated. This study aimed to investigate the analgesic effect of HBO in a CPSP rat model and the role of spinal cord adenosine circulation in HBO-induced analgesia. A skin/muscle incision and retraction (SMIR) rat model was used to mimic CPSP, and HBO treatment (2.5 atmospheric absolute, 60 minutes) was administered once daily for 5 consecutive days beginning 3 days after surgery. The role of spinal cord adenosine circulation in HBO-induced analgesia was investigated using β-methylene ADP (a CD73 inhibitor), 8-cyclopentyl-1,3-dipropylxanthine (an A1R antagonist), or an intrathecal injection of adenosine. The mechanical paw withdrawal threshold was determined at different timepoints before and after surgery. The spinal cord adenosine and adenosine triphosphate (ATP) contents were analyzed using high-performance liquid chromatography, and the spinal cord expression of adenosine-1 receptor (A1R), extracellular 5′-nucleotidase (CD73), and adenosine kinase (ADK) was examined by Western blotting and immunofluorescence staining. The results showed that the mechanical paw withdrawal threshold of the ipsilateral hind paw and the adenosine content decreased, and the spinal cord expression of A1R, CD73, and ADK and ATP content increased within 14 days after surgery. HBO treatment alleviated mechanical allodynia, reduced ATP content, and increased adenosine content by activating CD73 but downregulated the spinal cord expression of A1R, CD73, and ADK. Intrathecal adenosine alleviated mechanical allodynia after SMIR and downregulated the spinal cord expression of A1R and CD73, and intrathecal β-methylene ADP or 8-cyclopentyl-1,3-dipropylxanthine attenuated the analgesic effect of HBO treatment on SMIR-induced CPSP. PerspectiveSpinal cord adenosine is involved in the occurrence and development of CPSP, and HBO treatment alleviates CPSP by regulating adenosine production/metabolism in the spinal cord. Thus, HBO may be employed for the treatment of CPSP with favorable efficacy.

Hyperbaric Oxygen Therapy as a Novel Approach to Modulating Macrophage Polarization for the Treatment of Glioblastoma.

Glioblastoma multiforme (GBM) is a highly aggressive brain cancer with a poor prognosis despite current treatments. This is partially attributed to the immunosuppressive environment facilitated by tumor-associated macrophages, which predominantly underlie the tumor-promoting M2 phenotype. This study investigated the potential of hyperbaric oxygen (HBO) therapy, traditionally used to treat conditions such as decompression sickness, in modulating the macrophage phenotype toward the tumoricidal M1 state and disrupting the supportive tumor microenvironment. HBO has direct antiproliferative effects on tumor cells and reduces hypoxia, which may impair angiogenesis and tumor growth. This offers a novel approach to GBM treatment by targeting the role of the immune system within the tumor microenvironment. The effects of HBO on macrophage polarization and GBM cell viability and apoptosis were evaluated in this study. We detected that HBO promoted M1 macrophage cytokine expression while decreasing GBM cell viability and increasing apoptosis using GBM cell lines and THP-1-derived macrophage-conditioned media. These findings suggest that HBO therapy can shift macrophage polarization toward a tumoricidal M1 state. This can improve GBM cell survival and offers a potential therapeutic strategy. In conclusion, HBO can shift macrophages from a tumor-promoting M2 phenotype to a tumoricidal M1 phenotype in GBM. This can facilitate apoptosis and, in turn, improve treatment outcomes.

Hyperbaric Oxygen Therapy Reduces the Traumatic Brain Injury-Mediated Neuroinflammation Through Enrichment of Prevotella Copri in the Gut of Male Rats.

Gastrointestinal dysfunction frequently occurs following traumatic brain injury (TBI) and significantly increases posttraumatic complications. TBI can lead to alterations in gut microbiota. The neuroprotective effects of hyperbaric oxygen (HBO) have not been well recognized after TBI. The study''s aim was to investigate the impact of HBO on TBI-induced dysbiosis in the gut and the pathological changes in the brain following TBI. Anesthetized male Sprague-Dawley rats were randomly assigned to three groups: sham surgery plus normobaric air (21% oxygen at 1 atmospheres absolute), TBI (2.0atm) plus normobaric air, and TBI (2.0atm) plus HBO (100% oxygen at 2.0 atmospheres absolute) for 60min immediately after TBI, 24h later, and 48h later. The brain injury volume, tumor necrosis factor-α expression in microglia and astrocytes, and neuronal apoptosis in the brain were subsequently determined. The V3-V4 regions of 16S ribosomal rRNA in the fecal samples were sequenced, and alterations in the gut microbiome were statistically analyzed. All parameters were evaluated on the 3rd day after TBI. Our results demonstrated that HBO improved TBI-induced neuroinflammation, brain injury volume, and neuronal apoptosis. HBO appeared to increase the abundance of aerobic bacteria while inhibiting anaerobic bacteria. Intriguingly, HBO reversed the TBI-mediated decrease in Prevotella copri and Deinococcus spp., both of which were negatively correlated with neuroinflammation and brain injury volume. TBI increased the abundance of these gut bacteria in relation to NOD-lik0065 receptor signaling and the proteasome pathway, which also exhibited a positive correlation trend with neuro inflammation and apoptosis. The abundance of Prevotella copri was negatively correlated with NOD-like receptor signaling and the Proteasome pathway. Our study demonstrated how the neuroprotective effects of HBO after acute TBI might act through reshaping the TBI-induced gut dysbiosis and reversing the TBI-mediated decrease of Prevotella copri.

Hyperbaric oxygen therapy promotes the browning of white fat and contributes to the healing of diabetic wounds.

Non-healing wounds are one of the chronic complications of diabetes and have remained a worldwide challenge as one of the major health problems. Hyperbaric oxygen (HBO) therapy is proven to be very successful for diabetic wound treatment, for which the molecular basis is not understood. Adipocytes regulate multiple aspects of repair and may be therapeutic for inflammatory diseases and defective wound healing associated with aging and diabetes. Endothelial cell-derived extracellular vesicles could promote wound healing in diabetes. To study the mechanism by which HBO promotes wound healing in diabetes, we investigated the effect of HBO on fat cells in diabetic mice. A diabetic wound mouse model was established and treated with HBO. Haematoxylin and eosin (H&E) staining and immunofluorescence were used for the analysis of wound healing. To further explore the mechanism, we performed whole-genome sequencing on extracellular vesicles (EVs). Furthermore, we conducted in vitro experiments. Specifically, exosomes were collected from human umbilical vein endothelial cell (HUVEC) cells after HBO treatment, and then these exosomes were co-incubated with adipose tissue. The wound healing rate in diabetic mice treated with HBO was significantly higher. HBO therapy promotes the proliferation of adipose precursor cells. HUVEC-derived exosomes treated with HBO significantly promoted fat cell browning. These data clarify that HBO therapy may promote vascular endothelial cell proliferation and migration, and promote browning of fat cells through vascular endothelial cells derived exosomes, thereby promoting diabetic wound healing. This provides new ideas for the application of HBO therapy in the treatment of diabetic trauma.

Effect of hyperbaric oxygen treatment on patients with heatstroke complicated by multiple organ dysfunction:A retrospective study

BackgroundThe benefits of hyperbaric oxygen (HBO) in treating animals with heat stroke (HS) have been established. This study aims to retrospectively analyze the effect of HBO on multiple organ dysfunction following HS in humans. MethodsRetrospective data were collected from patients with HS admitted to our hospital in the past 7 years. Patients were categorized into groups based on whether they received HBO therapy. The study compared various factors, including sequential organ failure assessment (SOFA) and acute physiology and chronic health evaluation-Ⅱ (APACHE-Ⅱ) scores, mortality rates, neurological function scores, serum myocardial enzyme levels, liver, kidney, and coagulation function indicators, blood routine results, electrolyte levels, and modified Barthel index (MBI) score for standard daily living ability before treatment and after 2 and 4 weeks of treatment. ResultsThe mortality rates in the HBO and control group were 0% and 8.49%, respectively. Upon admission, the HBO group had higher SOFA and APACHE-Ⅱ scores and lower neurological, coagulation, and liver functions than those of the control group. HBO treatment significantly improved SOFA, APACHE-Ⅱ, and neurological scores while relieving levels of alanine aminotransferase, aspartate aminotransferase, creatinine, and myocardial enzymes. Additionally, it mitigating lymphocyte and platelet count decline caused by HS. The MBI score was significantly enhanced after treatment in the HBO group. ConclusionsClinical practice advocates administering HBO therapy to patients with severe illness, organ damage, and nerve impairment. Compared with conventional treatment, combined HBO therapy demonstrated superior efficacy in alleviating multiple organ dysfunction and improving daily living ability in patients with HS.

Hyperbaric oxygen therapy alleviates intestinal dysfunction following traumatic brain injury via m6A regulation.

Hyperbaric oxygen (HBO) therapy can attenuate neurological impairment after traumatic brain injury (TBI) and alleviate intestinal dysfunction. However, the role and mechanism of HBO therapy in intestinal dysfunction following TBI remain unclear. Herein, by establishing a mouse model of controlled cortical impact (CCI), we found that HBO therapy reduced histopathological lesions and decreased the levels of inflammatory and oedema proteins in the intestinal tissues of mice 10 days after TBI. We also showed that HBO therapy improved microbiome abundance and probiotic (particularly g_Bifidobacterium) colonisation in mice post-CCI. Then, we identified that the m6A level imcreased notably in injured cortical tissue of CCI+HBO group compared with the CCI group following CCI. Thus, our results suggested that HBO therapy could alleviate TBI-induced intestinal dysfunction and m6A might participate in this regulation process, which provides new insights for exploring the specific mechanism and targets of HBO in the treatment of intestinal dysfunction after TBI, thereby improving the therapeutic effect of HBO.

Hyperbaric oxygen alleviates selective domains of cognitive and motor deficits in female 5xFAD mice.

Treatment of Alzheimer's disease (AD) has been limited to managing of symptoms or anti-amyloid therapy with limited results and uncertainty. Seeking out new therapies that can reverse the effects of this devastating disease is important. Hyperbaric oxygen (HBO) therapy could be such a candidate as it has been shown to improve brain function in certain neurological conditions. Furthermore, the role sex plays in the vulnerability/resilience to AD remains equivocal. An understanding of what makes one sex more vulnerable to AD could unveil new pathways for therapy development. In this study, we investigated the effects of HBO on cognitive, motor, and affective function in a mouse model of AD (5xFAD) and assessed protein oxidation in peripheral tissues as a safety indicator. The motor and cognitive abilities of 5xFAD mice were significantly impaired. HBO therapy improved cognitive flexibility and associative learning of 5xFAD females but not males, but HBO had no effect other aspects of cognition. HBO also reversed AD-related declines in balance but had no impact on gait and anxiety-like behavior. HBO did not affect body weights or oxidative stress in peripheral tissues. Our study provides further support for HBO therapy as a potential treatment for AD and emphasizes the importance of considering sex as a biological variable in therapeutic development. Further investigations into the underlying mechanisms of HBO's sex-specific responses are warranted, as well as optimizing treatment protocols for maximum benefits.

Hyperbaric Oxygen (HBO) Effects on Blood Count Recovery and Post-Transplant Outcomes Following High-Dose Therapy and Autologous HSPC Transplantation for Multiple Myeloma: A Multicenter Phase II Randomized Clinical Trial

Background: By reducing systemic erythropoietin (EPO) levels, in vivo studies showed that hyperbaric oxygen (HBO) promoted homing of transplanted umbilical cord hematopoietic stem/progenitor cells (HSPC) to the bone marrow. In a pilot study, we demonstrated that HBO in autologous HSPC transplantation (auto-HSPC) was well tolerated. Time to absolute neutrophil (ANC) recovery was correlated with HBO-mediated reduction in EPO levels. Methods: In this phase II multicenter clinical trial, patients with multiple myeloma (MM) receiving high-dose melphalan and auto-HSPC were randomized 1:1 between HBO and no HBO. HBO was given as 100% oxygen, 2.5 ATA for a total of 90 min, in a single treatment on Day 0, 6 hours before cell infusion. The study's primary objective was to evaluate the effect of HBO on blood count recovery, filgrastim use, blood transfusions, and length of hospitalization (LOH). Exploratory objectives include HBO effects on EPO and IL-15 measured at several time points (pre-conditioning, Day 0 pre-HBO, 6- and 8-hours following HBO, and Days 1-3, 7 and 15 post-transplant). In addition, we explore HBO effects on Day 15 NK cell recovery. Results: A total of 99 patients were enrolled, with 52 randomized to HBO. Baseline characteristics were well balanced except for cell dose, with higher odds that patients with lower cell dose were treated with HBO. There was insufficient evidence of a difference between the two groups regarding time to neutrophil recovery, filgrastim use, blood transfusions, or LOH. Patients randomized to receive HBO were 1.7 (95% CI: 1.1-2.7) times more likely to have lymphocyte recovery (ALC) to > 0.5 k/µL by any given day compared to control (Figure-1). EPO levels (only University of Rochester Medical Center patients) were lower for HBO versus placebo on Day 1 (unadjusted p = 0.02), but there was insufficient evidence of a difference at other time points (Figure-2). Regarding immune reconstitution, IL-15 levels were not significantly different between the two groups. Significant correlation was found between Day 2 IL-15 levels and ALC recovery (p=0.01). We observed higher median NK cell count at Day 15 in the HBO arm (246 vs. 183), but this did not reach statistical significance (P=0.59). Conclusions: HBO resulted in lower EPO levels at Day +1 of auto-HSPC, translating to faster ALC recovery with no effect on neutrophil recovery. Longer follow-up is needed to determine if this will impact progression free survival. Higher NK cell recovery in the HBO arm compared to the non-HBO was not significant to account for the improvement in ALC recovery in the HBO arm. A pilot study (NCT04862676) is ongoing to determine if multiple HBO treatments can keep EPO levels low beyond Day +1 and impact outcomes.

A Pilot Study to Determine the Safety and Efficacy of Repeated Hyperbaric Oxygen Therapy in Multiple Myeloma Patients Undergoing High-Dose Therapy and Autologous Stem/Progenitor Cell Transplantation

Background Serum erythropoietin (EPO) negatively impacts hematopoietic stem cell homing and engraftment. Hyperbaric oxygen (HBO) therapy can reduce serum EPO in healthy volunteers and when given prior to stem cell infusion may improve engraftment after hematopoietic stem cell transplant (HSCT). We previously performed a phase II trial randomizing patients with multiple myeloma undergoing high dose melphalan and autologous HSCT 1:1 between a single HBO treatment and no HBO. HBO was given as 100% oxygen, 2.5 ATA for a total of 90 min, in a single treatment on Day 0 prior to the transplant. A total of 99 patients were enrolled with 52 randomized to HBO. HBO significantly reduced EPO levels for the first 24 hours after auto transplant, but EPO levels quickly rebounded by 48 hours after transplant. We hypothesized multiple HBO treatments will keep EPO levels low during the duration of stem cell homing (i.e: the first 72 hours after HSCT) and may improve neutrophil and NK cell recovery. Methods We performed a pilot study to evaluate the safety and tolerability of multiple HBO treatments during autologous HSCT. Patients with multiple myeloma undergoing autologous HSCT were eligible. Patients received HBO therapy, consisting of hyperbaric oxygen at 2.5 ATA for a total of 90 minutes breathing 100% oxygen on days 0 (prior to HSCT), 1, and 2 of transplant. The primary objective of this pilot study was to determine the safety of repeated HBO therapy in the setting, as defined by treatment limiting toxicity (TLT) including occurrence of seizure disorder, pneumothorax, death, or any irreversible grade Ill or any grade IV toxicity within 24 hours of HBO therapy. Secondary objectives were to determine the effects of multiple HBO therapy on neutrophil count recovery and the effect of multiple HBO on serum EPO. Results 10 patients have been enrolled that are evaluable for the primary objective. All patients had multiple myeloma and 4 were female. 9/10 patients successfully completed all 3 HBO treatments and 1/10 completed HBO on days 1 and 2 only because of ear pain on day 0. No patients experienced treatment limiting toxicity. The median times to neutrophil and platelet engraftment was 12 days (range 11-14) and 16 days (range 14-28), respectively. The median length of hospitalization was 13 days (range 12-16). Febrile neutropenia occurred in 3/10 patients with just one incidence of documented infection. This was significantly less than the rate of febrile neutropenia in patients receiving a single treatment of HBO or no HBO (81% and 47%, respectively, p<0.05). 3 patients required red blood cell transfusion and 5 platelet transfusion. Conclusions Multiple HBO treatment were well tolerated without treatment limiting toxicity during autologous HSCT for multiple myeloma.

Hyperbaric oxygen improves cerebral ischemia-reperfusion injury in rats via inhibition of ferroptosis

Background: Our previous study found that hyperbaric oxygen (HBO) attenuated cognitive impairment in mice induced by cerebral ischemia-reperfusion injury (CIRI). However, its mechanism of action is not fully understood. In this study, we aimed to establish a rat model of cerebral ischemia-reperfusion, explore the possible role of ferroptosis in the pathogenesis of CIRI, and observe the effect of HBO on ferroptosis-mediated CIRI. Methods: Sprague Dawley (SD) rats were randomly divided into control, model, Ferrostatin-1 (Fer-1), HBO and Fer-1+ HBO groups. Morris water maze, myelin basic protein (MBP) and β-tubulin immunoreactivity were assessed to evaluate the neuroprotective effects of HBO on cerebral ischemia reperfusion injury. Ferroptosis were examined to investigate the mechanism underlying the effects of HBO. Results: Our result showed that Fer-1 and HBO improved learning and memory ability in the navigation trail and probe trail of the Morris water maze and increased MBP and β-tubulin immunoreactivity of the cortex in the model rats. The levels of ferritin, malondialdehyde (MDA) and glutathione (GSH) in the serum were also reversed by Fer-1 and HBO treatment. Mitochondrial cristae dissolution and vacuolization were observed in the model group by transmission electron microscopy and these conditions were improved in the Fer-1 and HBO groups. Furthermore, Fer-1 and HBO treatment reversed Prostaglandin-Endoperoxide Synthase 2 (PTGS2), Iron Responsive Element Binding Protein 2 (IREB2), acyl-CoA synthetase long chain family member 4 (ACSL4) and Solute Carrier Family 7 Member 11 (SLC7A11) mRNA levels and Transferrin Receptor 1 (TFR1), ferritin light chain (FTL), ferritin heavy chain 1 (FTH1), glutathione peroxidase 4 (GPX4), Nuclear factor E2-related factor 2 (Nrf2), lysophosphatidylcholine acyltransferase 3 (LPCAT3), c-Jun N-terminal kinase (JNK), phosphorylated c-Jun N-terminal kinase (P-JNK) phosphorylated Extracellular signal-regulated protein kinase (P-ERK) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) protein levels. The above changes were more pronounced in Fer-1+ HBOGroup. Discussion: The results of the present study indicated that HBO improves cerebral ischemia-reperfusion injury in rats, which may be related to inhibition of ferroptosis. This also means that ferroptosis may become a new target of HBO against CIRI.

Hyperbaric oxygen therapy suppresses hypoxia and reoxygenation injury to retinal pigment epithelial cells through activating peroxisome proliferator activator receptor-alpha signalling.

Retinal ischemia followed by reperfusion (IR) is a common cause of many ocular disorders, such as age-related macular degeneration (AMD), which leads to blindness in the elderly population, and proper therapies remain unavailable. Retinal pigment epithelial (RPE) cell death is a hallmark of AMD. Hyperbaric oxygen (HBO) therapy can improve IR tissue survival by inducing ischemic preconditioning responses. We conducted an in vitro study to examine the effects of HBO preconditioning on oxygen-glucose deprivation (OGD)-induced IR-injured RPE cells. RPE cells were treated with HBO (100% O2 at 3 atmospheres absolute for 90 min) once a day for three consecutive days before retinal IR onset. Compared with normal cells, the IR-injured RPE cells had lower cell viability, lower peroxisome proliferator activator receptor-alpha (PPAR-α) expression, more severe oxidation status, higher blood-retinal barrier disruption and more elevated apoptosis and autophagy rates. HBO preconditioning increased PPAR-α expression, improved cell viability, decreased oxidative stress, blood-retinal barrier disruption and cellular apoptosis and autophagy. A specific PPAR-α antagonist, GW6471, antagonized all the protective effects of HBO preconditioning in IR-injured RPE cells. Combining these observations, HBO therapy can reverse OGD-induced RPE cell injury by activating PPAR-α signalling.

Hyperbaric oxygen and treadmill exercise partially prevented bone loss and bone microarchitecture deterioration in ovariectomized rats.

Previous studies have demonstrated the beneficial effects of treadmill exercise (EX) on osteoporosis, and of hyperbaric oxygen (HBO) on osteoblast and osteoclast formation in vitro. We investigated the effects of HBO and the combination of HBO and EX on osteoporosis in ovariectomized rats. Forty 3-month-old female Sprague-Dawley rats were randomly divided into 5 groups (n = 8): a sham control group (Control); an ovariectomy group; an ovariectomy with treadmill exercise treatment group; an ovariectomy with HBO treatment group; and an ovariectomy with HBO treatment combined with treadmill exercise group. The HBO exposures were 203 kPa, 85-90% O₂, 90 min and the exercise regimen was 20 m·min⁻¹, 40 min·day¹, 5° slope. Both treatments were administered once daily, five days a week for 12 weeks until the rats were sacrificed. All three treatments (HBO, exercise, and both combined) significantly promoted the expression of the osteoblast-related gene and oxidative metabolism-related gene (PGC-1α). They also exerted significant inhibitory effects on the osteoclast-related mRNA expression (RANKL) and bone resorption marker CTX-I. Additionally, exercise and the combination exercise-HBO treatment increased serum superoxide dysmutase (SOD) and sclerostin expression. No significant between-group difference was observed. Hyperbaric oxygen, exercise, and the combination ameliorated bone microarchitecture deterioration and ovariectomy-induced bone loss in rats, and these inhibitory effects may be associated with the increased SOD and up-regulated PGC-1α.

Hyperbaric oxygen ameliorates neuronal injury and neurological function recovery in rats with intracerebral hemorrhage by silencing microRNA-204-5p-targeted chloride channel protein 3.

Hyperbaric oxygen (HBO) therapy is of clinical utility in patients with transient cerebral ischemia. The investigatory study was to identify the potential regulatory mechanism of HBO treatment on neuronal injury and neurological function recovery in rats with intracerebral hemorrhage (ICH). Firstly, the rat model of ICH was established by collagenase, and the experimental rats were treated with HBO at 2.5 absolute atmospheres for 60 min each time. Next, lentivirus interfering with microRNA (miR)-204-5p or chloride channel protein 3 (CLCN3) expression was injected via the tail vein. Afterward, neurological function assessment was conducted, serum S100β and NSE contents were detected by enzymer-linked immunosorbent assay, and pathological conditions of brain tissue were observed by hematoxylin-eosin staining. Terminal deoxynucleotidyl transferase mediated dUTP nick end labeling staining was used to detect neuronal apoptosis. The results showed that HBO alleviated neuronal injury and neurological function recovery in ICH rats and reduced serum S100β and NSE content (all P<0.05). At the same time, overexpressing miR-204-5p or depleting CLCN3 further promoted the therapeutic effect of HBO on ICH rats (all P<0.05), while silencing miR-204-5p or elevating CLCN3 did oppositely (all P<0.05). In conclusion, HBO alleviates neuronal injury and neurological function recovery in ICH rats by silencing miR-204-5p-targeted CLCN3.

Anti-inflammatory effect of hyperbaric oxygen in the treatment of peptic ulcer disease: review

OBJECTIVE: Based on the analysis of literature data, highlight the mechanisms of anti-inflammatory action of hyperbaric oxygenation (HBO) in peptic ulcer of the stomach and duodenum (PUS and D).MATERIALS AND METHODS: The subject of study was scientific publications on the use of hyperbaric oxygenation (GBT) in treatment (PUS and D). The search was carried out on the international databases Elibrary, Pub Med, Scopus, Google Scholar from 1980–2022. A total of 38 literature sources were selected, of which at least 60% were published within the last five years. RESULTS: The effectiveness of the therapeutic effect of HBO (ulcer healing rate) in PUS and D depends on the location and size of the ulcer defect on the wall of the stomach or duodenum. At the moment, there is no conclusive data on the optimal number of HBO sessions required to achieve the maximum therapeutic effect in the treatment of PUS and D. DISCUSSION: The leading link in hyperoxic sanogenesis in this pathology is the anti-inflammatory effect of hyperbaric oxygen (HBO2), which is realized by: a) through stimulation of mucocyte formation; b) through regulation of HBO2 qualitative composition of mucocyte secretion; c) by stimulating the formation of bicarbonates by additional cells and increasing the sensitivity of these cells to their endogenous stimulant -solar acid (HCl); d) through the effect of HBO2 on gastrin formation (HCl stimulant), as well as on the diffusion of HCl from the gastric lumen into its capillary network. Together, this leads to a rapid cessation of pain syndrome, which creates conditions for the elimination of dyspeptic syndrome. This is realized through the restoration of the myoelectric activity of the stomach wall and duodenum, the regulation of the myogenic tone of their walls, as well as the elimination of the violation of gastric accommodation in the conditions of HBO. CONCLUSION: The anti-inflammatory effect of HBO2 in the treatment of PUS and D allows us to consider hyperbaric oxygenation as an integral part of the treatment of ulcerative lesion of the upper gastrointestinal tract.

Real-world evidence of hyperbaric oxygen therapy on cardiovascular outcomes in patients with chronic osteomyelitis

BackgroundThe effectiveness of hyperbaric oxygen (HBO) therapy for chronic osteomyelitis remains inconclusive. In particular, recent studies have shown that chronic osteomyelitis is a crucial risk factor for cardiovascular diseases. However, the preventive effect of HBO on cardiovascular events has not been reported in patients with chronic osteomyelitis. MethodsWe conducted a population-based cohort study to evaluate the impact of HBO on patients with chronic osteomyelitis. Overall, 5312 patients with chronic osteomyelitis were selected from the Taiwan National Health Insurance Database to evaluate the impact of HBO in patients with chronic osteomyelitis. Propensity-score (PS) matching and inverse probability weighting (IPTW) were employed to balance covariates between the HBO and non-HBO groups. The primary outcome was all-cause mortality. The secondary outcomes were myocardial infarction (MI) and stroke hospitalisation. Furthermore, we evaluated the appropriate timing for HBO intervention by the restricted cubic spline (RCS) functions. ResultsAfter 1:4 PS-matching, the HBO group (n = 265) was associated with lower 1-year mortality (hazard ratio [HR], 0.49; 95 % confidence interval [CI], 0.25–0.95) than the non-HBO group (n = 994); this was consistent with the IPTW weighting results (HR, 0.25; 95 % CI, 0.20–0.33). The risk of stroke was lower in the HBO group (HR, 0.46; 95 % CI, 0.34–0.63) than that in the non-HBO group. However, HBO therapy failed to reduce the risk of MI. Using the RCS model, patients with intervals within 90 days (HR, 1.38; 95 % CI, 1.04–1.84) presented a significant risk of 1-year mortality. After 90 days, as the length of interval increased, the risk gradually decreased and became insignificant. ConclusionThe present study revealed that adjunctive HBO could benefit the 1-year mortality and stroke hospitalisation in patients with chronic osteomyelitis. HBO was recommended to be initiated within 90 days of chronic osteomyelitis hospitalisation.

Hyperbaric Oxygenation Prevents Loss of Immature Neurons in the Adult Hippocampal Dentate Gyrus Following Brain Injury

A growing body of evidence suggests that hyperbaric oxygenation (HBO) may affect the activity of adult neural stem cells (NSCs). Since the role of NSCs in recovery from brain injury is still unclear, the purpose of this study was to investigate the effects of sensorimotor cortex ablation (SCA) and HBO treatment (HBOT) on the processes of neurogenesis in the adult dentate gyrus (DG), a region of the hippocampus that is the site of adult neurogenesis. Ten-week-old Wistar rats were divided into groups: Control (C, intact animals), Sham control (S, animals that underwent the surgical procedure without opening the skull), SCA (animals in whom the right sensorimotor cortex was removed via suction ablation), and SCA + HBO (operated animals that passed HBOT). HBOT protocol: pressure applied at 2.5 absolute atmospheres for 60 min, once daily for 10 days. Using immunohistochemistry and double immunofluorescence labeling, we show that SCA causes significant loss of neurons in the DG. Newborn neurons in the subgranular zone (SGZ), inner-third, and partially mid-third of the granule cell layer are predominantly affected by SCA. HBOT decreases the SCA-caused loss of immature neurons, prevents reduction of dendritic arborization, and increases proliferation of progenitor cells. Our results suggest a protective effect of HBO by reducing the vulnerability of immature neurons in the adult DG to SCA injury.

Mild Hyperbaric Oxygen Exposure Enhances Peripheral Circulatory Natural Killer Cells in Healthy Young Women

Mild hyperbaric oxygen (HBO) enhances oxygen absorption in blood, relieving fatigue without causing oxidative stress. The benefits of mild HBO have been recognized in the treatment of lifestyle-related diseases and hypertension, but no research has been conducted on its effects on immunity. The aim of the present study is to investigate the effect of mild HBO on natural killer (NK) cells and cytokines in healthy young women. This crossover randomized control trial was conducted with 16 healthy young women. Participants were randomly exposed to normobaric oxygen (NBO; 1.0 atmospheres absolute (ATA), 20.8% oxygen) and mild HBO conditions (1.4 ATA, 35-40% oxygen, injected 18L oxygen per minute) in a hyperbaric oxygen chamber for 70 min. Heart rate, parasympathetic activity, NK cell count, interleukin (IL)-6, IL-12p70 and derivatives of reactive oxygen metabolites (d-ROMs) were measured before and after both exposures. In the NBO condition, parasympathetic activity remained unchanged, whereas after mild HBO exposure, parasympathetic activity was significantly increased. NK cells remained unchanged after NBO exposure, while NK cells were increased after exposure to mild HBO. Exposure to mild HBO did not increase d-ROM values, IL-6 and IL-12p70 protein levels. These findings suggest that exposure to mild HBO can be a useful protocol to increase NK cells by regulating parasympathetic activity via increasing oxygen delivery.

Hyperbaric oxygen preconditioning for prevention of acute high-altitude diseases: Fact or fiction?

Acute high-altitude diseases, including acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE), have been recognized as potentially lethal diseases for altitude climbers. Various preconditioning stimuli, including hyperbaric oxygen (HBO), have been proposed to prevent acute high-altitude diseases. Herein, we reviewed whether and how HBO preconditioning could affect high-altitude diseases and summarized the results of current trials. Evidence suggests that HBO preconditioning may be a safe and effective preventive method for acute high-altitude diseases. The proposed mechanisms of HBO preconditioning in preventing high-altitude diseases may involve: 1) protection of the blood-brain barrier and prevention of brain edema, 2) inhibition of the inflammatory responses, 3) induction of the hypoxia-inducible factor and its target genes, and 4) increase in antioxidant activity. However, the optimal protocol of HBO preconditioning needs further exploration. Translating the beneficial effects of HBO preconditioning into current practice requires the "conditioning strategies" approach. More large-scale and high-quality randomized controlled studies are needed in the future.

Comparison of hyperbaric oxygen and ozone treatment for ischemia/re-perfusion injury in an experimental testicular torsion model.

This study aims to compare the effects of medical ozone (MO) therapy and hyperbaric oxygen (HBO) therapy in an experimental testicular torsion model by measuring the oxidant and antioxidant markers and examining the histopathological tissue damage findings. Thirty-two Wistar rats are used and are divided into four groups; (1) sham group (SG), (2) only ischemia/reperfusion (I/R) by testicular torsion, (3) HBO administered group, and (4) MO administered group. No torsion was conducted in the SG. In all other groups, rats underwent testicular torsion followed by detorsion to create an I/R model. After I/R, HBO was injected in the HBO group, and in the MO group, intraperitoneal ozone was applied. At the end of 1 week, testicular tissues were obtained for biochemical analyzes and histopathological examinations. Biochemically, malondialdehyde (MDA) levels were measured for oxidant activity, and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels were measured for antioxidant activity. Furthermore, the testicles were evaluated histopathologically. Both HBO and MO have significantly decreased MDA levels, compared with sham and I/R groups, resulting in decreased oxidation effects. The antioxidant GSH-Px levels in the HBO and MO groups were significantly higher than in the sham and I/R groups. In addition, the antioxidant SOD levels in the HBO group were significantly higher than sham, I/R, and MO groups. Therefore, the antioxidant effect of HBO was observed to be superior to MO, specifically considering SOD levels. Histopathologically, there was no significant difference between the groups (p>0.05). The study may extrapolate that both HBO and MO are antioxidant agents that can be used in testicular torsion. HBO treatment might improve the cellular antioxidant capacity due to increased antioxidant marker levels more than MO therapy. However, further studies are needed with a larger sample size.