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.

Hyperbaric Oxygen Treatment in Spinal Cord Injury Recovery: Profiling Long Noncoding RNAs.

STUDY DESIGN: A functional, transcriptome, and long noncoding RNAs (lncRNAs) expression analysis in the spinal cord of mice after hyperbaric oxygen (HBO) treatment. OBJECTIVE: We aimed to explore the mechanism by which HBO treats spinal cord injury (SCI) at the level of lncRNAs. SUMMARY OF BACKGROUND DATA: Immense amounts of research have established that HBO treatment promotes the recovery of neurological function after SCI. The mechanism of action remains to be clarified. METHODS: High-throughput RNA sequencing, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were used to profile lncRNA expression and analyze biological function in the spinal cords of mice from sham-operated, SCI, and HBO-treated groups. The differential expression of lncRNA between the groups was assessed using real-time quantitative polymerase chain reaction. RESULTS: Differential expression across 577 lncRNAs was identified among the three groups. GO analysis showed that free ubiquitin chain polymerization, ubiquitin homeostasis, DNA replication, synthesis of RNA primer, single-stranded telomeric DNA binding, and alpha-amylase activity were significantly enriched. Kyoto Encyclopedia of Genes and Genomes enrichment analysis displayed that vitamin B6 metabolism, one carbon pool by folate, DNA replication, lysine degradation, beta-alanine metabolism, fanconi anemia pathway, and Notch signal pathway were the main pathways with enrichment significance. LncRNAs NONMMUT 092674.1, NONMMUT042986.2, and NONMMUT018850.2 showed significantly different expression between the SCI and the other two groups (P<0.05, <0.01). CONCLUSIONS: This study is the first to determine the expression profiles of lncRNAs in the injured spinal cord after HBO treatment. We identified several important dysregulated lncRNAs in this setting. These results help us better understand the mechanism by which HBO treats SCI and provide new potential therapeutic targets for SCI.

The mechanism by which hyperbaric oxygen treatment alleviates spinal cord injury: genome-wide transcriptome analysis.

Accumulating studies have demonstrated that hyperbaric oxygen (HBO) treatment alleviates spinal cord injury (SCI). However, the underlying mechanism by which HBO alleviates SCI remains to be elucidated. In this study, we performed genome-wide transcriptional profiling of the spinal cord between SCI mice and mice that received HBO treatment by high-throughput RNA sequencing at 1 week after SCI. We also compared genome-wide transcriptional profiles from SCI mice and sham-operated mice. We found 76 differentially co-expressed genes in sham-operated mice, SCI mice, and HBO-treated SCI mice. Using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, we identified the biological characteristics of these differentially expressed genes from the perspectives of cell component, biological process, and molecular function. We also found enriched functional pathways including ferroptosis, calcium signaling pathway, serotonergic synapse, hypoxia-inducible factor-1 signaling pathway, cholinergic synapse, and neuroactive ligand-receptor interaction. We performed quantitative reverse transcription-polymerase chain reaction and validated that HBO treatment decreased the expression of Hspb1 (heat shock protein beta 1), Hmox1 (heme oxygenase 1), Ftl1 (ferritin light polypeptide 1), Tnc (tenascin C) and Igfbp3 (insulin-like growth factor binding protein 3) and increased the expression of Slc5a7 (solute carrier family 5 choline transporter member 7) after SCI. These results revealed the genome-wide transcriptional profile of the injured spinal cord after HBO treatment. Our findings contribute to a better understanding of the mechanism by which HBO treats SCI and may provide new targets for SCI intervention.