Effect of VEGF and CX43 on the promotion of neurological recovery by hyperbaric oxygen treatment in spinal cord-injured rats

Hyperbaric Oxygen Therapy Inhibits Neuronal Ferroptosis After Spinal Cord Injury in Mice

STUDY DESIGN

Basic science study investigating the potential molecular mechanisms of hyperbaric oxygen (HBO) therapy in mice with spinal cord injury (SCI).

OBJECTIVE

We aimed to explore the intrinsic mechanisms of HBO for SCI through the lens of ferroptosis in the subacute phase.

SUMMARY OF BACKGROUND DATA

HBO has been observed to facilitate the restoration of neurological function subsequent to SCI. Ferroptosis is a distinct cellular death mechanism that can be distinguished from apoptosis, necrosis, and autophagy. However, the precise relationship between these two phenomena remains poorly understood.

METHODS

We established an SCI model and employed a range of techniques, including behavioral assessments, electron microscopy, immunofluorescence, RT-qPCR, Western blotting (WB), Glutathione (GSH) measurement, and iron assay, to investigate various aspects of HBO therapy on SCI in mice. These included analyzing mitochondrial morphology, neuronal count, GSH levels, iron levels, and the expression of genes (Acyl-CoA synthetase family member-2, Iron-responsive element-binding protein-2) and proteins (Glutathione peroxidase 4; system Xc-light chain) associated with ferroptosis. The study included three groups: Sham-operated, SCI, and HBO. Group comparisons were performed using one-way analysis of variance and one-way repeated measures analysis of variance, followed by Tukey's post hoc test. Statistical significance was set at a P < 0.05.

RESULTS

Our findings revealed that HBO therapy significantly enhanced the recovery of lower limb motor function in mice following SCI in the subacute phase. This was accompanied by upregulated expression of GPX4 and system Xc-light chain proteins, elevated GSH levels, increased number of NeuN+ cells, decreased expression of the iron-responsive element-binding protein-2 gene, and reduced iron concentration.

CONCLUSIONS

Our research suggests that HBO therapy has the potential to be an effective treatment for SCI in the subacute phase by mitigating ferroptosis.

An Overview of Recent Developments in the Management of Burn Injuries

According to the World Health Organization (WHO), around 11 million people suffer from burns every year, and 180,000 die from them. A burn is a condition in which heat, chemical substances, an electrical current or other factors cause tissue damage. Burns mainly affect the skin, but can also affect deeper tissues such as bones or muscles. When burned, the skin loses its main functions, such as protection from the external environment, pathogens, evaporation and heat loss. Depending on the stage of the burn, the patient's condition and the cause of the burn, we need to choose the most appropriate treatment. Personalization and multidisciplinary collaboration are key to the successful management of burn patients. In this comprehensive review, we have collected and discussed the available treatment options, focusing on recent advances in topical treatments, wound cleansing, dressings, skin grafting, nutrition, pain and scar tissue management.

Hyperbaric Oxygen Therapy-Induced Molecular and Pathway Changes in a Rat Model of Spinal Cord Injury: A Proteomic Analysis

Hyperbaric Oxygen Therapy (HBOT) has definitive therapeutic effects on spinal cord injury (SCI), but its mechanism of action is still unclear. Here, we've conducted a systemic proteomic analysis to identify differentially expressed proteins (DEPs) between SCI rats and HBOT + SCI rats. The function clustering analysis showed that the top enriched pathways of DEPs include oxygen transport activity, oxygen binding, and regulation of T cell proliferation. The results of functional and signal pathway analyses indicated that metabolic pathways, thermogenesis, LXR/RXR activation, acute phase response signaling, and the intrinsic prothrombin pathway in the SCI + HBOT group was higher than SCI group.

Survey of Molecular Mechanisms of Hyperbaric Oxygen in Tissue Repair

For more than six decades, hyperbaric oxygen (HBO) has been used for a variety of indications involving tissue repair. These indications comprise a wide range of diseases ranging from intoxications to ischemia-reperfusion injury, crush syndrome, central nervous injury, radiation-induced tissue damage, burn injury and chronic wounds. In a systematic review, the molecular mechanisms triggered by HBO described within the last two decades were compiled. They cover a wide range of pathways, including transcription, cell-to-cell contacts, structure, adhesion and transmigration, vascular signaling and response to oxidative stress, apoptosis, autophagy and cell death, as well as inflammatory processes. By analyzing 71 predominantly experimental publications, we established an overview of the current concepts regarding the molecular mechanisms underlying the effects of HBO. We considered both the abovementioned pathways and their role in various applications and indications.

A review on the neuroprotective effects of hyperbaric oxygen therapy

Hyperbaric oxygen therapy, intermittent breathing of 100% oxygen at a pressure upper than sea level, has been shown to be some of the neuroprotective effects and used therapeutically in a wide range of neurological disorders. This review summarizes current knowledge about the neuroprotective effects of hyperbaric oxygen therapy with their molecular mechanisms in different models of neurological disorders.

The Treatment of Perioperative Spinal Cord Injury With Hyperbaric Oxygen Therapy: A Case Report

STUDY DESIGN

Case report (level IV evidence).

OBJECTIVE

To describe a potential novel application of hyperbaric oxygen therapy (HBOT) in the successful treatment of a postoperative spinal cord injury.

SUMMARY OF BACKGROUND DATA

A 68-year-old man presented with an acute spinal cord injury (ASIA impairment scale D), on the background of degenerative lower thoracic and lumbar canal stenosis. He underwent emergent decompression and instrumented fusion (T9-L5), with an uncomplicated intraoperative course and no electrophysiological changes. Immediate postoperative assessment demonstrated profound bilateral limb weakness (1/5 on the Medical Research Council [MRC] grading scale, ASIA impairment scale B), without radiological abnormality.

METHODS

Conventional medical management (hypertension, level 2 care) was instigated with the addition of Riluzole, with no effect after 30 hours. At 36 hours 100% oxygen at 2.8 atmospheres was applied for 90 minutes, and repeated after 8 hours, with a further three treatments over 48 hours.

RESULTS

The patient demonstrated near-immediate improvement in lower limb function to anti-gravity (MRC grading 3/5) after one treatment. Motor improvement continued over the following treatments, and after 2 weeks the patient was ambulatory. At 4 months, the patient demonstrated normal motor function with no sphincteric disturbance.

CONCLUSION

The application of HBOT contributed to the immediate and sustained improvement (ASIA B to ASIA E) in motor recovery after postoperative spinal cord injury. HBOT may represent a new avenue of therapy for spinal cord injury, and requires further prospective investigation.

LEVEL OF EVIDENCE

4.

Molecular and Therapeutic Aspects of Hyperbaric Oxygen Therapy in Neurological Conditions

In hyperbaric oxygen therapy (HBOT), the subject is placed in a chamber containing 100% oxygen gas at a pressure of more than one atmosphere absolute. This treatment is used to hasten tissue recovery and improve its physiological aspects, by providing an increased supply of oxygen to the damaged tissue. In this review, we discuss the consequences of hypoxia, as well as the molecular and physiological processes that occur in subjects exposed to HBOT. We discuss the efficacy of HBOT in treating neurological conditions and neurodevelopmental disorders in both humans and animal models. We summarize by discussing the challenges in this field, and explore future directions that will allow the scientific community to better understand the molecular aspects and applications of HBOT for a wide variety of neurological conditions.

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

OBJECTIVE

This 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.

METHODS

Forty 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.

RESULTS

Significant 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).

CONCLUSIONS

HBO treatment has a great efficacy in acute SCI patients. HBO therapy at early stage of acute SCI is beneficiary to the recovery.

Hyperbaric oxygen treatment of spinal cord injury in rat model

Background

The purpose of this study was to investigate the therapeutic effects and mechanisms of hyperbaric oxygen (HBO) treatment on rats following spinal cord injury (SCI).

Methods

A total of 45 Sprague-Dawley (SD) rats were randomly divided into three groups. Sham-SCI group was surgically exposed but not subjected to the SCI procedure. SCI-control group was administered SCI and treated with regular air. SCI-HBO group was administered SCI and HBO treatment. Neuromotor functions were examined using the Basso, Beattie, and Bresnahan (BBB) locomotor rating scale and the inclined plane assessment at before SCI (baseline) and after SCI. Superoxide dismutase (SOD) activities and malondialdehyde (MDA) levels were measured.

Results

Starting from Day 1 after SCI but except Day 2, the SCI-HBO group has significantly higher BBB scores than the SCI-control group. After SCI, the maximum inclination angles at which rats could maintain were significantly lower in both SCI groups. But the maximum angles were significantly bigger for the rats in the SCI-HBO group than those on the SCI-control group at 5, 10 and 20 days after SCI. SOD activities in SCI-HBO rats were significantly higher and MDA levels were significantly lower than in SCI-control rats, at two and five days after SCI. There was also less cystic degeneration of spinal cord in SCI-HBO rats, compared to SCI-control rats.

Conclusions

These results suggest that HBO treatment has a therapeutic value in treating SCI. Increased oxygen free radical scavenging and reduced lipid oxidation may be one of the mechanisms.

Hyperbaric oxygen therapy of spinal cord injury

Spinal cord injury (SCI) is a complex disease process that involves both primary and secondary mechanisms of injury and can leave patients with devastating functional impairment as well as psychological debilitation. While no curative treatment is available for spinal cord injury, current therapeutic approaches focus on reducing the secondary injury that follows SCI. Hyperbaric oxygen (HBO) therapy has shown promising neuroprotective effects in several experimental studies, but the limited number of clinical reports have shown mixed findings. This review will provide an overview of the potential mechanisms by which HBO therapy may exert neuroprotection, provide a summary of the clinical application of HBO therapy in patients with SCI, and discuss avenues for future studies.

Current and emerging treatment options for spinal cord ischemia

Spinal cord infarction (SCI) is a rare but disabling disorder caused by a wide spectrum of conditions. Given the lack of randomized-controlled trials, contemporary treatment concepts are adapted from guidelines for cerebral ischemia, atherosclerotic vascular disease, and acute traumatic spinal cord injury. In addition, patients with SCI are at risk for several potentially life-threatening but preventable systemic and neurologic complications. Notably, there is emerging evidence from preclinical studies for the use of neuroprotection in acute ischemic injury of the spinal cord. In this review, we discuss the current state of the art for the therapy and prevention of SCI and highlight potential emerging treatment concepts awaiting translational adoption.

Hyperbaric Oxygen Treatment Protects Against Spinal Cord Injury by Inhibiting Endoplasmic Reticulum Stress in Rats

STUDY DESIGN

Experimental animal study of treatment of SCI.

OBJECTIVE

To explore whether HBO treatment protects against secondary SCI by inhibiting the ER stress response.

SUMMARY OF BACKGROUND DATA

SCI is a neurological disorder that can severely limit the execution of the simplest day-to-day functions. ER stress plays an important role in the induction of neuronal apoptosis after SCI. HBO treatment can alleviate secondary injury and benefit neurological recovery after SCI, but the effect of HBO on ER stress response after SCI is yet to be characterized.

METHODS

The spinal cord of rats was injured via T10 laminectomy. Experimental animals were randomly assigned to 1 of 3 groups: sham-operated, SCI, and SCI+HBO. Each group was analyzed 1, 2, 3, 7, and 14 days after injury. Neurological recovery was evaluated using the Basso-Beattie-Bresnahan (BBB) scoring system and the TdT-mediated dUTP nick-end labeling reaction was carried out to visualize apoptotic cells. The expression of ER stress-related factors was evaluated by immunohistochemical, western blot, and real-time reverse transcription-polymerase chain reaction analyses.

RESULTS

SCI-induced apoptosis and an increase in the levels of CCAAT-enhancer-binding protein homologous protein (CHOP), and caspase-12 and caspase-3 compared with the sham-operated group. HBO treatment decreased CHOP and caspase-12 and caspase-3 expression as well as apoptosis compared with the SCI group. In addition, BBB scores were improved in the SCI+HBO relative to the SCI group at 7 and 14 days.

CONCLUSION

These results suggest that HBO treatment alleviates secondary injury to the spinal cord by inhibiting ER stress induced apoptosis, thereby promoting the recovery of neurological function.

LEVEL OF EVIDENCE

N/A.

Effect of mesenchymal stem cells transplantation combining with hyperbaric oxygen therapy on rehabilitation of rat spinal cord injury

OBJECTIVE

To investigate the effect of BMSCs transplantation plus hyperbaric oxygen (HBO) on repair of rat SCI.

METHODS

Seventy five male rats were divided randomly into five groups: sham, vehicle, BMSCs transplantation group, combination group, 15 rats in each group. Every week after the SCI onset, all animals were evaluated for behavior outcome by Basso-Beattle-Bresnahan (BBB) score and inclined plane test. Axon recovery was examined with focal spinal cord tissue by electron microscope at 6 weeks after the SCI onset. HE staining and BrdU staining were performed to examine the BMSCs and lesion post injury. Somatosensory evoked potential (SEP) testing was performed to detect the recovery of neural conduction.

RESULTS

Results from the behavior tests from combination group were significant higher than rats which received only transplantation or HBO treatment. Results from histopathology showed favorable recovery from combination group than other treatment groups. The number of BrdU(+) in combination group were measureable more than transplantation group (P < 0.05). The greatest decrease in TNF-α, IL-1β, IL-6, IFN-α determined by Elisa assay in combination group were evident too.

CONCLUSIONS

BMSCs transplantation can promote the functional recovery of rat hind limbs after SCI, and its combination with HBO has a synergistic effect.

The effect of estrogen-related receptor α on the regulation of angiogenesis after spinal cord injury

Estrogen receptor-related receptor-α (ERRα) is an orphan member of the nuclear receptor superfamily that interacts with peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) to stimulate vascular endothelial growth factor (VEGF) expression and angiogenesis in a hypoxia-inducible factor-1α-independent pathway. Although it is not regulated by any natural ligand, the action of ERRα can be blocked by the synthetic molecule XCT790. In the present study, Sprague-Dawley rats were randomly allocated to a sham group, injury-saline group or injury-XCT90 group. A modified Allen's weight-drop method was applied to induce the acute traumatic spinal cord injury (SCI) model in these rats, and an injection of XCT790 was administered every 24h, starting half an hour after the SCI contusion. Histological analyses revealed that XCT790 significantly aggravated tissue damage and decreased the number of ERRα-positive cells at 1, 3 and 7 days after SCI. Western blot and quantitative real-time polymerase chain reaction (qRT-PCR) analyses also indicated that XCT790 dramatically repressed the expression of ERRα, thus reducing the expression of VEGF and angiopoietin-2 (Ang-2) throughout the duration of the experiment, but the expression of PGC-1α was not affected. Immunofluorescence analyses indicated that vascular density and endothelial cell proliferation were decreased in the injury-XCT90 group compared with the injury-saline group. These results suggest that ERRα is involved in mediating angiogenesis after SCI in the rat traumatic SCI model.