A narrative review of methane in treating neurological diseases.

Methane has shown protective effects on a variety of diseases. Among these, neurological diseases have attracted much attention. However, there are many different indicators and application methods of methane in the treatment of neurological diseases. In this review, we summarize the indicators related to the protective effects of methane and evaluate the preparation and administration of methane. Thus, we hope to offer available indicators and effective ways to produce and administer methane in future research.

Effects of hyperbaric oxygen on Notch signaling pathway after severe carbon monoxide poisoning in mice.

Demyelination of the cerebral white matter is the most common pathological change after carbon monoxide (CO) poisoning. Notch signaling, the mechanism underlying the differentiation of astrocytes and oligodendrocytes, is critical to remyelination of the white matter after brain lesion. The purpose of this work was to determine the effects of hyperbaric oxygen (HBO) on Notch signaling pathway after CO poisoning for the explanation of the protective effects of HBO on CO-poisoning-related cerebral white matter demyelination. The male C57 BL/6 mice with severe CO poisoning were treated by HBO. And HBO therapy shortened the escape latency and improved the body mass after CO poisoning. HBO therapy also significantly suppressed protein and mRNA levels of Notch1 and Hes5 after CO poisoning. Our findings suggested that HBO could suppress the activation of Notch signaling pathway after CO poisoning, which is the mechanism underlying the neuroprotection of HBO on demyelination after severe CO poisoning.

Hydrogen exerts neuroprotective effects by inhibiting oxidative stress in experimental diabetic peripheral neuropathy rats.

Diabetic peripheral neuropathy (DPN) is a complex disorder caused by long-standing diabetes. Oxidative stress was considered the critical creed in this DPN pathophysiology. Hydrogen has antioxidative effects on diabetes mellitus and related complications. However, there is still no concern on the beneficial effects of hydrogen in DPN. This paper aimed to evaluate the effects of exogenous hydrogen to reduce the severity of DPN in streptozotocin-induced diabetic rats. Compared with hydrogen-rich saline treatment, hydrogen inhalation significantly reduced blood glucose levels in diabetic rats in the 4th and 8th weeks. With regard to nerve function, hydrogen administration significantly attenuated the decrease in the velocity of motor nerve conduction in diabetic animals. In addition, hydrogen significantly attenuated oxidative stress by reducing the level of malondialdehyde, reactive oxygen species, and 8-hydroxy-2-deoxyguanosine and meaningfully enhanced the antioxidant capability by partially restoring the activities of superoxide dismutase. Further studies showed that hydrogen significantly upregulated the expression of nuclear factor erythroid-2-related factor 2 and downstream proteins such as catalase and hemeoxygenase-1 in the nerves of diabetic animals. Our paper showed that hydrogen exerts significant protective effects in DPN by downregulating oxidative stress via the pathway of nuclear factor erythroid-2-related factor 2, which suggests its potential value in clinical applications.

Therapeutic effect of methane and its mechanism in disease treatment.

Methane is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms. It is abundant in marsh gas, livestock rumination, and combustible ice. Little is known about the use of methane in human disease treatment. Current research indicates that methane is useful for treating several diseases including ischemia and reperfusion injury, and inflammatory diseases. The mechanisms underlying the protective effects of methane appear primarily to involve anti-oxidation, anti-inflammation, and anti-apoptosis. In this review, we describe the beneficial effects of methane on different diseases, summarize possible mechanisms by which methane may act in these conditions, and discuss the purpose of methane production in hypoxic conditions. Then we propose several promising directions for the future research.

Characteristics of exogenous carbon monoxide deliveries.

Carbon monoxide (CO) has long been considered an environmental pollutant and a poison. Exogenous exposure to amounts of CO beyond the physiologic level of the body can result in a protective or adaptive response. However, as a gasotransmitter, endogenous CO is important for multiple physiologic functions. To date, at least seven distinct methods of delivering CO have been utilized in animal and clinical studies. In this mini-review, we summarize the exogenous CO delivery methods and compare their advantages and disadvantages.

Hypoxia therapy--a new hope for the treatment of mitochondrial dysfunctions.

Mitochondrial dysfunctions are characteristic features of numerous diseases and play a critical role in disease pathogenesis. Despite intensive research in this area, there are no approved therapies that directly target mitochondria. Recently a study by Jain et al. from Massachusetts General Hospital, USA reported the effectiveness of hypoxia for treatment of mitochondrial disease in mice. In this commentary, we summarized the potential mechanisms underlying the therapeutic effects of hypoxia on mitochondrial dysfunction, and clinical limitations of hypoxia as a therapy for human patients. We hope that our concerns will be helpful for further clinical studies addressing moderate hypoxia in mitochondrial dysfunction.

Neuroprotective effects of exogenous methane in a rat model of acute carbon monoxide poisoning.

OBJECTIVE: Delayed neuropsychological sequelae (DNS) are the most common and serious effects of severe carbon monoxide (CO) poisoning, occurring in approximately half of all CO poisoning cases. Growing evidence suggests that oxidative stress and secondary reactions in delayed brain injury are crucial to CO toxicity, similar to ischaemia-reperfusion injury. Exogenous methane plays a protective role in ischaemia-reperfusion injury by affecting key events through anti-oxidant, anti-inflammatory, and anti-apoptosis actions. Our study aimed to explore the potential of exogenous methane to relieve the severity of DNS. METHODS: Thirty-six male Sprague-Dawley (SD) rats were divided into three groups of normal-, CO- and CO plus methane-treated rats. The rats in the latter two groups were exposed to 1000 ppm CO for 40 min and then to 3000 ppm CO for another 20 min. Following CO exposure, saline or methane saline (10 ml/kg) was intraperitoneally administered to rats in the CO group or the CO plus methane group, respectively. On the ninth day after CO exposure, Morris water maze testing, histological analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) and immunohistochemical labelling were performed on 6 rats in each group. The remaining 6 rats in each group were used to detect oxidative damage markers, inflammatory cytokines and apoptosis proteins. RESULTS: Methane significantly improved CO-impaired pathological characteristics as well as learning and memory performance. In addition, methane significantly increased the superoxide dismutase (SOD) activity, lowered the CO-increased level of malondialdehyde (MDA) 3-nitrotyrosine (3-NT) and 8-hydroxy-2-deoxyguanosine (8-OHdG), inhibited levels of tumour necrosis factor-α (TNF-α), interleukin 1-ß (IL1-ß) and caspase-3 in the rat cerebral cortex and hippocampus but had no effect on IL-6 levels. CONCLUSION: The hippocampus was the main target of CO-induced alterations in the rat brain compared to the cerebral cortex. Methane treatment protected the rat brain from the harmful effects induced by CO exposure and improved the outcome of DNS through anti-oxidant, anti-inflammatory and anti-apoptosis activities.