Therapeutic Effect Of Hyperbaric Oxygen Research Articles

Hyperbaric oxygen therapy for the treatment of hypoxic/ischemic injury upon perinatal asphyxia-are we there yet?

Birth asphyxia and its main sequel, hypoxic-ischemic encephalopathy, are one of the leading causes of children's deaths worldwide and can potentially worsen the quality of life in subsequent years. Despite extensive research efforts, efficient therapy against the consequences of hypoxia-ischemia occurring in the perinatal period of life is still lacking. The use of hyperbaric oxygen, improving such vital consequences of birth asphyxia as lowered partial oxygen pressure in tissue, apoptosis of neuronal cells, and impaired angiogenesis, is a promising approach. This review focused on the selected aspects of mainly experimental hyperbaric oxygen therapy. The therapeutic window for the treatment of perinatal asphyxia is very narrow, but administering hyperbaric oxygen within those days improves outcomes. Several miRNAs (e.g., mir-107) mediate the therapeutic effect of hyperbaric oxygen by modulating the Wnt pathway, inhibiting apoptosis, increasing angiogenesis, or inducing neural stem cells. Combining hyperbaric oxygen therapy with drugs, such as memantine or ephedrine, produced promising results. A separate aspect is the use of preconditioning with hyperbaric oxygen. Overall, preliminary clinical trials with hyperbaric oxygen therapy used in perinatal asphyxia give auspicious results.

Clinical analysis of hyperbaric oxygen combined with subdural drilling and drainage in the management of subdural effusion type IV with intracranial infection in infant patients.

To explore the therapeutic effect of hyperbaric oxygen combined with subdural drilling and drainage (SDD) on subdural effusion type IV with intracranial infection in infant patients. This retrospective controlled study included 328 infant patients with subdural effusion type 4 with intracranial infection between January 2005 and January 2023. 178 patients were treated by hyperbaric oxygen combined with SDD (group A). 142 cases were treated with SDD (group B). 97 infants were only received hyperbaric oxygen (group C). Clinical outcomes, the control time of intracranial infection, complications, and the degree of brain re-expansion after 6 months of treatment were compared among the three groups. According to the comprehensive evaluation of treatment effectiveness and imaging results, it is divided into four levels: cured, significantly effective, improved, and ineffective. No patient died during follow-up. The three groups were similar regarding age, sex, the general information, and clinical symptoms (p > 0.05). All intracranial infections in the children were effectively controlled. There was no difference in infection control time between group A and group B, and there was no statistical significance. However, the control time of intracranial infection between the two groups was different from that of group C, which was statistically significant. Compared with group B and group C, the degree of brain re-expansion in group A has obvious advantages and significant differences. The effective rates of the three groups were 83.7%, 58.5%, and 56.7%, respectively. There were 28 cases of subcutaneous hydrops in group A and 22 cases of subcutaneous hydrops in group B after operation, and no other serious complications. The SDD is safe and effective for infant patients with intracranial infections through fluid replacement and intrathecal antibacterial. Hyperbaric oxygen is effective as an adjuvant therapy to promote brain re-expansion.

Anxiety and Obesity in Children: Anti-oxidative Medications and Hyperbaric Oxigenation Therapy

IntroductionObesity is a grave problem in pediatrics and child psychiatry. It was revealed that in many cases obesity has comorbidity with different mental disorders. Besides a number of endocrine disturbances, immune system deficiency and oxidative stress with free radical oxidation take part in pathogenesis of these phenomena.ObjectivesThe essence of the therapeutic effect of hyperbaric oxygen lies in the fact that under the influence of elevated barometric pressure, oxygen saturation of body fluids increases: blood, interstitial fluid, which deliver oxygen to organs and tissues, increasing oxygen supply to cells by 5-10 times and eliminating hypoxia (oxygen starvation tissues). Hyperbaric oxygen, normalizing blood circulation in tissues and metabolic processes at the cellular level, has a number of effects that favorably affect the patient’s condition: promotes the formation of a new vascular network in areas where it is damaged or insufficient, has anti-edematous, anti-inflammatory and wound healing effects, has an immunocorrective effect , normalizes hormonal status, enhances the action of a number of pharmacological agents. The aim of our research was to study effects of HBO on children suffering from anxiety and obesityas a result of the mental instability? S;eep disturbances and immune instabilityMethodsSessions of hyperbaric oxygenation were carried out at a pressure of 1.6 ATA: the first session lasted 45 minutes, subsequent sessions was 30 minutes. After HBO, each of the patients during the day showed a steady increase in the saturation index, which persisted until the morning of the next day. An analysis of fluctuations in the saturation index during the day showed its decrease in all patients to a minimum value at 8 am and its general dynamic increase from the beginning of hyperbaric oxygenation. Parameters of immune status, including serum concentrations of IgA, IgM and IgG, circulating immune complexes were studied in pediatric patients, aged from 10 to 14 years old, 42 girls and 34 girls. Mapping EEG was used for evaluation of electric brain activity.ResultsIt was found that HBO treatment normalized mental state: patients demonstrated less anxiety and overeating habits, тormalization of sleep, positive dynamics of sleep, reflected in the EEG pattern in the form of alpha waves. Immune reactions were changed: IgA, IgM and IgG, were increased and CIC serum level decreased.ConclusionsThe use of antioxidant therapy in combination with psychopharmacological drugs has long been a well-established method of treatment for a variety of psychopathological conditions. The inclusion of hyperbaric oxygenation in this complex also helps to achieve more distinct results in terms of weight loss in obesity and normalization of the mental state, improved sleep and significant immunocorrection.Disclosure of InterestNone Declared

Application of Whole-Body Hyperbaric Oxygen Therapy in the Treatment of Grade III Exposed Dog Bite Wounds.

Objective The aim of the study is to evaluate the therapeutic effect of hyperbaric oxygen in the treatment of grade III exposed dog bite wounds. Method Fifty-two patients with grade III dog bite wounds who were seen in the emergency department of our hospital from 2017 to 2021 were selected for this research. The participants were randomly divided into an experimental group and a control group, with 26 patients in each group. The experimental group received hyperbaric oxygen therapy (HBOT), and the control group received routine treatment. The patients were followed up for three months after the treatment concluded. The wound healing rate, infection rate, and healing time were measured and compared. Results The cure rate of the experimental group (96.2%) was higher than that of the control group (69.2%). The infection rate in the experimental group (3.8%) was lower than that of the control group (30.8%). The average cure time of the experimental group (9 ± 2.7) was lower than that of the control group (11 ± 3.4). The number of dressing changes in the experimental group (4 ± 3.0) was lower than that of the control group (7.5 ± 3.5), and there was a significant difference between the two groups (P < 0.05). Conclusion According to the results, HBOT of grade III dog bite wounds can promote wound healing, improve the cure, and reduce the wound infection rate. It should have a primary role in the clinical treatment of these wounds.

Therapeutic effects of hyperbaric oxygen: integrated review.

Hyperbaric oxygen therapy refers to inhalation of pure oxygen in a closed chamber. Hyperbaric oxygen has a therapeutic effect in numerous pathological conditions, such as decompression sickness, arterial gas embolism, carbon monoxide poisoning and smoke inhalation, osteomylitis, osteoradionecrosis and wound healing. Hyperbaric oxygen therapy is used for treating underlying hypoxia. This review indicates the action of hyperbaric oxygen on biochemical and various physiological changes in cellular level. Narrative review covers the current indications and contraindications of hyperbaric oxygen therapy. The review also focuses on the therapeutic effects of hyperbaric oxygen pretreatment and precondition in different pathological conditions. The complications and side effects of hyperbaric oxygen therapy are discussed.

The efficacy of hyperbaric oxygen in the treatment of sudden sensorineural hearing loss

Objective:To investigate the therapeutic effect of hyperbaric oxygen on sudden sensorineural hearing loss（SSNHL）. Method:One hundred and seven patients with SSNHL were selected, and were randomly divided into 3 groups according to admission order. Therapeutic schedule in group A （38 cases） consisted of hyperbaric oxygen treatment once a day for 10 consecutive days, then 1 day off treatment, and on treatment for another 10 consecutive days （20 treatments in total）. Twenty-seven patients in group B were treated with hyperbaric oxygen twice per day for a total of 10 days. Forty-two patients in group C didn't receive hyperbaric oxygen therapy. Meanwhile, all patients were given conventional treatment for 14 days in accordance with the recommendations of the otolaryngology, head and neck branch of the Chinese medical association for the diagnosis and treatment of sudden sensorineural hearing loss. Patients in group A underwent pure tone audiometry after the end of treatment, and patients in group B and C were reexamined 20 days after the start of treatment, and the treatment efficacy of the three groups was compared. Result:The overall effective rate of group A was 78.9%, and the improvement of hearing threshold was（27.2±17.5） dB HL. In group B, the overall effective rate was 81.5%, and the improvement of threshold value was（26.9±16.7） dB HL. The overall effective rate of group C was 61.9%, and the improvement of threshold value o was（17.6±18.5） dB HL. The effective rate of group C was significantly higher than that of group A or B, while there was no significant difference in efficacy between group A and group B. Conclusion:The efficacy of hyperbaric oxygen combined with drug therapy for SSNHL is better than that of drug therapy alone. Programs of different hyperbaric oxygen combined with drug therapy can be selected on an individual basis.

HBO Promotes the Differentiation of Neural Stem Cells via Interactions Between the Wnt3/β-Catenin and BMP2 Signaling Pathways

Hyperbaric oxygen (HBO) therapy may promote neurological recovery from hypoxic-ischemic encephalopathy (HIE). However, the therapeutic effects of HBO and its associated mechanisms remain unknown. The canonical Wnt/β-catenin signaling pathways and bone morphogenetic protein (BMP) play important roles in mammalian nervous system development. The present study examined whether HBO stimulates the differentiation of neural stem cells (NSCs) and its effect on Wnt3/β-catenin and BMP2 signaling pathways. We showed HBO treatment (2 ATA, 60 min) promoted differentiation of NSCs into neurons and oligodendrocytes in vitro. In addition, rat hypoxic-ischemic brain damage (HIBD) tissue extracts also promoted the differentiation of NSCs into neurons and oligodendrocytes, with the advantage of reducing the number of astrocytes. These effects were most pronounced when these two were combined together. In addition, the expression of Wnt3a, BMP2, and β-catenin nuclear proteins were increased after HBO treatment. However, blockade of Wnt/β-catenin or BMP signaling inhibited NSC differentiation and reduced the expression of Wnt3a, BMP2, and β-catenin nuclear proteins. In conclusion, HBO promotes differentiation of NSCs into neurons and oligodendrocytes and reduced the number of astrocytes in vitro possibly through regulation of Wnt3/β-catenin and BMP2 signaling pathways. HBO may serve as a potential therapeutic strategy for treating HIE.

Therapeutic Effects of Hyperbaric Oxygen in the Process of Wound Healing.

Chronic and non-healing wounds, especially diabetic foot ulcers and radiation injuries, imply remarkable morbidity with a significant effect on the quality of life and a high sanitary cost. The management of these wounds requires complex actions such as surgical debris, antibiotic treatment, dressings and even revascularization. These wounds are characterized by poor oxygen supply resulting in inadequate oxygenation of the affected tissue. The adjuvant treatment with hyperbaric oxygen therapy (HBOT) may increase tissue oxygenation favoring the healing of wounds which do not respond to the usual clinical care. The increase in the partial pressure of oxygen contributes to cover the energy demands necessary for the healing process and reduces the incidence of infections. Moreover, the increase in oxygen leads to the production of reactive species with hormetic activity, acting on signaling pathways that modulate the synthesis of inflammation mediators, antioxidants and growth factors which can contribute to the healing process. Studies performed with cell cultures and in animal models seem to demonstrate the beneficial effects of HBOT. However, clinical trials do not show such conclusive results; thus, additional randomized placebo-controlled studies are necessary to determine the real efficacy of HBOT and the mechanism of action for various types of wounds.

&lt;p&gt;Hyperbaric oxygen therapy attenuates neuronal apoptosis induced by traumatic brain injury via Akt/GSK3&amp;beta;/&amp;beta;-catenin pathway&lt;/p&gt;

BackgroundGiven that the therapeutic effect of hyperbaric oxygen (HBO) therapy on traumatic brain injury (TBI) has been debated for a long time, it is necessary to clarify the mechanism underlying the effect of HBO on acute TBI.MethodsThis study investigated the effect of HBO therapy on neuronal apoptosis induced by acute TBI using the mouse model of TBI. The number of apoptotic cells and expression of apoptosis-associated factors (including caspase 3, pAkt/Akt, pGSK3β/GSK3β, and β-catenin) in pericontusional cortices of mice exposed to sham, TBI, and TBI + HBO treatment were measured and analyzed using TUNEL assay, quantitative reverse-transcription PCR, and Western blot.ResultsResults showed that acute TBI increased the number of apoptotic neurons and mRNA expression and activated caspase 3 protein. With regard to proteins, acute TBI also resulted in decreased levels of pAkt/Akt, pGSK3β/GSK3β, and β-catenin, which facilitates neuronal apoptosis. This study shows that HBO therapy reversed these changes of pAkt/Akt, pGSK3β/ GSK3β, and β-catenin induced by acute TBI and attenuated the apoptotic process in the pericontusional cortex.ConclusionThis study demonstrates the beneficial effect of HBO therapy on neuronal apoptosis caused by acute TBI. Furthermore, the mechanism underlying the therapeutic effect of HBO on acute TBI partly involves the Akt/GSK3β/β-catenin pathway.

Evaluation of Hyperbaric Oxygen Treatment in Acute Traumatic Spinal Cord Injury in Rats Using Diffusion Tensor Imaging.

This study aimed to evaluate the therapeutic effect of hyperbaric oxygen (HBO) on acute spinal cord injury (SCI) by measuring the in vivo diffusion tensor imaging (DTI) parameters apparent diffusion coefficient (ADC) and fractional anisotropy (FA) and observing diffusion tensor tractography (DTT) of fiber bundle morphology. The rats were randomly divided into sham-operated (SH), SCI, and SCI and hyperbaric oxygen treatment (SCI + HBO) groups (n = 6 in each group). The Basso-Bettie-Bresnahan (BBB) score was used to evaluate motor function recovery, and DTI was performed on days 3, 7, 14, and 21 after surgery. BBB scores and FA values decreased significantly after SCI, while the two values significantly improved in the SCI + HBO group compared with the SCI group on days 7, 14, and 21. ADC increased significantly on days 14 and 21 postoperatively in the SCI group compared with the SH group but did not significantly differ between the SCI and SCI + HBO groups at any time point. BBB scores had the same variation trend with ADC values and FA values in all three groups. In the SH group, DTT showed a well-organized spinal cord, but the spinal cord showed interruptions at sites of injury after SCI. In conclusion, HBO promotes the recovery of neuronal function after SCI. Parameters of DTI, especially FA, can quantitatively evaluate the efficacy of HBO treatment in SCI, while DTT enables the visualization of the fiber tracking of spinal cord tracts.

Hyperbaric oxygen ameliorated the lesion scope and nerve function in acute spinal cord injury patients: A retrospective study

ObjectiveThis is a retrospective study to assess the therapeutic effect of hyperbaric oxygen (HBO) in early treatment of acute spinal cord injury (SCI) using magnetic resonance imaging (MRI) and electrophysiology in diagnosing. MethodsForty acute SCI patients from Sun Yat-Sen Memorial Hospital who were assigned into HBO treatment were included during August 2013 to October 2014.The patients with adverse reactions or contraindications for HBO were assigned as controls. Both of two groups (HBO and Control) received medicine treatment with Urbason, GM-1 and mecobalamine after surgery. ASIA and the Frankel scores were used to evaluate the therapeutic effect of HBO at the 15th and 30th day after HBO treatment by using MRI and electrophysiology features. ResultsSignificant therapeutic effect of HBO treatment on acute SCI patients was observed compared with the control group (P<0.05). Comparison for ASIA and Frankel scores showed that motor and neurological functions were significantly improved in HBO group at day 15 and day 30 post treatment. MRI images showed that the grade III injury in HBO group was significant lower than the control group. In comparison with the control, the peak of somatosensory evoked potential (SEP) and motor evoked potential (MEP) amplitude increased, the latency was shortened, and the conduction velocity of sensory nerve (SCV) and motor nerve (MCV) was significantly increased in the HBO group (P<0.05). ConclusionsHBO treatment has a great efficacy in acute SCI patients. HBO therapy at early stage of acute SCI is beneficiary to the recovery.

Hyperbaric oxygen alleviates the activation of NLRP-3-inflammasomes in traumatic brain injury

Growing evidence has demonstrated that the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP-3) inflammasome-mediated inflammatory pathways have been involved in the secondary injury of traumatic brain injury (TBI). In the present study, the authors investigated the effects of hyperbaric oxygen (HBO) therapy on the NLRP-3 inflammasome pathway following TBI. Following the evaluation of motor deficits and brain edema, the therapeutic effects of HBO on interleukin (IL)-1β and IL-18 expression were assessed, as well as NLRP-3 inflammasome activation following TBI. HBO may improve motor score and reduce brain edema, accompanied with the reduction of IL-1β and IL-18 during the 7-day observation period. Furthermore, HBO suppressed mRNA and protein expression of NLRP-3-inflammasome components, especially reducing NLRP-3 expression in microglia. Thus, these results suggested that HBO alleviates the inflammatory response in experimental TBI via modulating microglial NLRP-3-inflammasome signaling.

Cerebral injury induced by heat stroke and the therapeutic effect of hyperbaric oxygen therapy

With the global warming, the incidence of heat stroke was significantly higher than before. Severe heat stroke has a high mortality, high morbidity and consolidated central nervous system injury characteristics. The main features of severe heat stroke cerebral injury include cognitive impairment, delirium, convulsions and coma. Its mechanism is related with heat shock induced cerebral tissue ischemia and hypoxia, vascular dysfunction, secondary cascade inflammation and so on. Currently, the main treatment of heat stroke cerebral injury is the hypothermia therapy, dehydration for the reduction of intracranial pressure, naloxone and other cerebral protection and nutrition treatments. Hyperbaric oxygen therapy (HBOT) is effective in treating brain injury. HBOT can alleviate tissue ischemia and hypoxia, improve circulation, reduce cerebral edema, and anti-inflammatory, anti-oxidative damage, anti-apoptosis and other molecular biological effects. HBOT also play a wake up-promoting effect of nerve repair in the cerebral injury. The treatment of cerebral injury has been the difficulty and weakness of heat stroke research. Therefore, this article reviewed the epidemiology, pathogenesis, the therapeutic effect and mechanism of hyperbaric oxygen on cerebral injury in severe heat stroke to clarify the advantages of HBOT and to provide experimental basis for further research.

Beneficial effects of hyperbaric oxygen on edema in rat hippocampus following traumatic brain injury.

Hyperbaric oxygen (HBO) therapy helps alleviate secondary injury following brain trauma [traumatic brain injury (TBI)], although the mechanisms remain unclear. In this study, we assessed recovery of post-TBI spatial learning and memory in rats using the Morris water maze (MWM) and measured changes in apparent diffusion coefficient in the hippocampus by diffusion-weighted imaging (DWI) to evaluate possible therapeutic effects of HBO on TBI-associated brain edema. DWIs were obtained 8, 24, 48 h, 7 days, and 14 days post-TBI. Daily HBO therapy significantly improved post-TBI MWM performance and reduced edema in the ipsilateral hippocampus, suggesting that the therapeutic efficacy of HBO is mediated, at least in part, by a reduction in brain edema.

Hyperbaric oxygen therapy ameliorates TNBS-induced acute distal colitis in rats.

BackgroundThis study investigated the therapeutic effects of hyperbaric oxygen in experimental acute distal colitis focusing on its effect on the production of pro-inflammatory cytokines, nitric oxide and hypoxia-inducible factor 1alpha.MethodsColitis was induced with a rectal infusion of 150 mg/kg of TNBS under anesthesia with Ketamine (50 mg/kg) and Xylazine (10 mg/kg). Control animals received only rectal saline. After colitis induction, animals were subjected to two sessions of hyperbaric oxygen and were then euthanized. The distal intestine was resected for macroscopic analysis, determination of myeloperoxidase activity, western-blotting analyses of inducible nitric oxide synthase and cyclooxygenase-2 expression and immunohistochemical analysis of hypoxia-inducible factor 1alpha and cyclooxygenase-2. Cytokines levels in the distal intestine were measured using an enzyme-linked immunosorbent assay.ResultsHyperbaric oxygen therapy attenuated the severity of acute distal colitis, with reduced macroscopic damage score. This effect was associated with prevention in the increase of pro-inflammatory cytokine production; myeloperoxidase activity, in the expression of inducible nitric oxide synthase and cyclooxygenase-2. Finally, hyperbaric oxygen inhibited the acute distal colitis-induced up-regulation of hypoxia-inducible factor 1alpha.ConclusionsThe results indicate that hyperbaric oxygen attenuates the severity of acute distal colitis through the down-regulation of pro-inflammatory events.

Effect of hyperbaric oxygen on the level of nitric oxide and endothelin-1 in patients with chronic cerebral circulation insufficiency

Objective To observe the therapeutic effects of hyperbaric oxygen and its effects on the serum levels of NO and ET-1 in patients with the chronic cerebral circulation insufficiency(CCCI).Methods A total of 110 chronic cerebral circulation insufficiency patients randomly classified into control group (n =50) and treatment group (n =60).Control group patients with CCCI routine drug treatment,treatment group on the basis of the above-mentioned medication combined with hyperbaric oxygen treatment,Clinical symptoms,NO and ET-1 levels in sera were evaluated 20 days after treatment.Results Compared with those of group with hyperbaric oxygen combination routine therapy,clinical symptom (91.7％ vs 70.0％) in control group was significantly different (x2 =8.61,P ＜ 0.01),and serum levels of NO markedly increased (30.45 ± 5.91) pg/ml and (45.21 ±7.51)pg/ml(t =4.38,P ＜0.01),and serum levels of ET-1 markedly decreased (50.62 ±3.82) μmol/L and (39.80 ±5.42)μmol/L(t =4.26,P ＜0.01).Treatment group before and after treatment compared with serum levels of ET-1,NO differences were statistically significant (P ＜ 0.01).Conclusions Hyperbaric oxygen is effective to treat CCCI and down-regulate ET-1 and up-regulate NO secretion.Regulation on the level of plasma ET-1 and NO is beneficial to the repair of damaged endothelia of blood vessel. Key words: Nursing; Chronic cerebral circulation insufficiency; Hyperbaric oxygen; Endothelin1 ; Nitric oxide

Effect of hyperbaric oxygen on Vibrio vulnificus and murine infection caused by it

ABSTRACTVibrio vulnificus is a bacterium known to cause fatal necrotizing soft tissue infection in humans. Here, a remarkable therapeutic effect of hyperbaric oxygen (HBO) on V. vulnificus infection provoked by its injection into mouse footpads is described. HBO was shown to be bactericidal to this bacterium in vitro as well as in the infected tissue. The bactericidal activity of HBO was shown to be due to reactive oxygen species (ROS), the efficacy of HBO against V. vulnificus infection being accounted for by the high sensitivity of this bacterium to ROS. Besides being somewhat weak in ROS‐inactivating enzyme activities, this bacterium is also unusually sensitive to ultraviolet light and other DNA‐damaging agents. It seems likely that the sensitivity of V. vulnificus to HBO is mainly due to its poor ability to repair oxidative damage to DNA. These findings encourage clinical application of HBO against potentially fatal V. vulnificus infection in humans.

Therapeutic effect of hyperbaric oxygen treatment combined with pharmacotherapy for sudden deafness: A retrospective study

To compare the therapeutic effect of hyperbaric oxygen (HBO) treatment and pharmacotherapy with that of pharmacotherapy alone in sudden deafness (SD) patients, and to evaluate the impact of therapeutic time window on the therapeutic effect, a total of 264 patients with SD were assigned into HBO group and control group. Patients in the HBO group received routine pharmacotherapy and HBO treatment, and those in the control group were only routinely treated with drugs. Acoustic impedance measurement and pure tone audiometry were performed before and after treatment. The hearing after treatment at different time windows was compared with that before treatment. The overall efficacy in the HBO group was significantly superior to that of the control group (P 0.05). The results demonstrated that the efficacy of HBO combined treatment was superior to that of routine pharmacotherapy for SD patients, and HBO treatment can favorably improve the hearing of these patients. HBO treatment initiated early after symptom onset (<2 weeks) is recommended, and that initiated 2 weeks after symptom onset predicts a poor outcome. Key words: Sudden deafness, hyperbaric oxygen, time window, therapeutic efficacy.

Neuroprotective Effect of Hyperbaric Oxygen Therapy on Anterior Ischemic Optic Neuropathy

The study investigated the therapeutic effect of hyperbaric oxygen (HBO) on anterior ischemic optic neuropathy in a rodent model (rAION). rAION was laser-induced in one eye of 63 mice. The fellow (uninjured) eye served as an internal control. Thirty-three mice underwent two 90-min sessions of 100% oxygen (2 atm) treatment immediately following injury and one session daily thereafter for up to 14 days. The remaining mice were untreated. Retinas were harvested at different time points, and mRNA levels of various genes were analyzed by real-time polymerase chain reaction and histologic study. Untreated mice: day 1 post-rAION – SOD-1 (oxidative-stress-related) decreased to 82% of control (uninjured eye) levels (P < 0.05), Caspase-3 (proapoptotic) decreased to 89%, Bcl-xL mildly increased (117%; all NS); day 3 – HO-1 and endothelial nitric oxide synthase (eNOS; ischaemia-related) decreased to 74%, and Bcl-2-associated X protein, Caspase-3, and B-cell lymphoma 2 (Bcl-2; apoptotic) increased by 170, 120, and 111%, respectively (all NS); day 21 – HO-1 increased to 222% (NS) and eNOS decreased to 48% (P < 0.05). Treated mice: day 1 – SOD-1 and Caspase-3 remained unchanged, Bcl-2 and Bcl-xL mildly increased (112 and 126% respectively); day 3 – HO-1 and eNOS increased, apoptosis-related gene decreased; day 21 – SOD-1 decreased whereas eNOS increased (P < 0.05), and HO-1 increased to a lesser degree than without treatment. None of the oxygen-treated animals had retinal ganglion cell loss or a decrease in Thy-1 expression. In conclusion, HBO treatment after rAION induction influences the expression of apoptosis-related genes as well as oxidative-stress-induced and ischaemia-related genes and may exert a neuroprotective effect.

Randomised phase II trial of hyperbaric oxygen therapy in patients with chronic arm lymphoedema after radiotherapy for cancer

Background A non-randomised phase II study suggested a therapeutic effect of hyperbaric oxygen (HBO) therapy on arm lymphoedema following adjuvant radiotherapy for early breast cancer, justifying further investigation in a randomised trial. Methods Fifty-eight patients with ⩾15% increase in arm volume after supraclavicular ± axillary radiotherapy (axillary surgery in 52/58 patients) were randomised in a 2:1 ratio to HBO ( n = 38) or to best standard care ( n = 20). The HBO group breathed 100% oxygen at 2.4 atmospheres absolute for 100 min on 30 occasions over 6 weeks. Primary endpoint was ipsilateral limb volume expressed as a percentage of contralateral limb volume. Secondary endpoints included fractional removal rate of radioisotopic tracer from the arm, extracellular water content, patient self-assessments and UK SF-36 Health Survey Questionnaire. Findings Of 53/58 (91.4%) patients with baseline assessments, 46 had 12-month assessments (86.8%). Median volume of ipsilateral limb (relative to contralateral) at baseline was 133.5% (IQR 126.0–152.3%) in the control group, and 135.5% (IQR 126.5–146.0%) in the treatment group. Twelve months after baseline the median (IQR) volume of the ipsilateral limb was 131.2% (IQR 122.7–151.5%) in the control group and 133.5% (IQR 122.3–144.9%) in the treatment group. Results for the secondary endpoints were similar between randomised groups. Interpretation No evidence has been found of a beneficial effect of HBO in the treatment of arm lymphoedema following primary surgery and adjuvant radiotherapy for early breast cancer.