Preconditioning with Ginsenoside Rg3 mitigates cardiac injury induced by high-altitude hypobaric hypoxia exposure in mice by suppressing ferroptosis through inhibition of the RhoA/ROCK signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Ginseng has historically been utilized as a conventional herbal remedy and dietary supplement to enhance physical stamina and alleviate fatigue. The primary active component of Ginseng, Ginsenoside Rg3 (GS-Rg3), possesses diverse pharmacological properties including immune modulation and anti-inflammatory effects. Furthermore, GS-Rg3 has demonstrated efficacy in mitigating tissue and organ damage associated with metabolic disorders such as hypertension, hyperglycemia, and hyperlipidemia. Nevertheless, its potential impact on high-altitude cardiac injury (HACI) remains insufficiently explored. AIM OF THE STUDY: The aim of this study was to examine the potential cardioprotective effects of Ginsenoside Rg3, and to investigate how Ginsenoside Rg3 preconditioning can enhance high-altitude cardiac injury by inhibiting the RhoA/ROCK pathway and ferroptosis in cardiac tissue. The findings of this study may contribute to the development of novel therapeutic strategies using traditional Chinese medicine for high-altitude cardiac injury, based on experimental evidence. MATERIALS AND METHODS: A hypobaric hypoxia chamber was employed to simulate hypobaric hypoxia conditions equivalent to an altitude of 6000 m. Through a randomization process, groups of six male mice were assigned to receive either saline, Ginsenoside Rg3 at doses of 15 mg/kg or 30 mg/kg, or lysophosphatidic acid (LPA) at 1 mg/kg. The impact of Ginsenoside Rg3 on high altitude-induced arrhythmias was evaluated using electrocardiography. Cardiac pathology sections stained with hematoxylin and eosin were evaluated for damage, with the extent of cardiomyocyte damage observed via transmission electron microscopy. The impact of Ginsenoside Rg3 on high-altitude cardiac injury was investigated through analysis of serum biomarkers for cardiac injury (CK-MB, BNP), inflammatory cytokines (TNF, IL-6, IL-1ß), reactive oxygen species (ROS) and glutathione (GSH). The expression levels of hypoxia and hypoxia-related proteins in myocardial tissues from each experimental group were assessed using Western blot analysis. Following a review of the existing literature, the traditional regulatory mechanisms of ferroptosis were examined. Immunofluorescence staining of cardiac tissues and Western blotting techniques were utilized to investigate the impact of Ginsenoside Rg3 on cardiomyocyte ferroptosis through the RhoA/ROCK signaling pathway under conditions of hypobaric hypoxia exposure. RESULTS: Pre-treatment with Ginsenoside Rg3 improved high altitude-induced arrhythmias, reduced cardiomyocyte damage, decreased cardiac injury biomarkers and inflammatory cytokines, and lowered the expression of hypoxia-related proteins in myocardial tissues. Both Western blotting and immunofluorescence staining of cardiac tissues demonstrated that exposure to high-altitude hypobaric hypoxia results in elevated expression of ferroptosis and proteins related to the RhoA/ROCK pathway. Experimental validation corroborated that the role of the RhoA/ROCK signaling pathway in mediating ferroptosis. CONCLUSIONS: The findings of our study suggest that preconditioning with Ginsenoside Rg3 may attenuate cardiac injury caused by high-altitude hypobaric hypoxia exposure in mice by inhibiting ferroptosis through the suppression of the RhoA/ROCK signaling pathway. These findings contribute to the current knowledge of Ginsenoside Rg3 and high-altitude cardiac injury, suggesting that Ginsenoside Rg3 shows potential as a therapeutic agent for high-altitude cardiac injury.

The Chinese Herbal Medicine Li Qi Huo Xue Di Wan Ameliorates Ischemia or Hypoxia-Induced Cardiac Injury and Remodeling in the Heart Through a Mechanism Involving Reduction of Necroptosis.

Li Qi Huo Xue Di Wan (LQHXDW), a Chinese herbal medicine, is commonly used to treat symptoms such as palpitations, chest tightness, chest pain, and shortness of breath. However, its potential to reduce ischemia or hypoxia-induced cardiac injury and remodeling, along with the precise mechanisms involved, remains unclear. This study aims to investigate the effects of LQHXDW on cardiac injury and remodeling induced by ischemia or hypoxia, both in vivo and in vitro, and to elucidate the underlying mechanisms. The mouse heart was subjected to ischemia for 14 days, showing evident myocardial injury and notable cardiac remodeling, accompanied by a reduction in cardiac function; these phenomena were reversed in the presence of LQHXDW. In the cultured cardiomyocyte exposed to hypoxia, incubation with LQHXDW increased the cell viability and reduced lactate dehydrogenase release. Mechanistically, LQHXDW exerted inhibitory effect on the phosphorylation levels of RIPK1, RIPK3, and MLKL as well as oxidative stress in the mice hearts suffered ischemia and the cultured cardiomyocytes exposed to hypoxia. Using the methods of ultra-high performance liquid chromatography-quadrupole time-of-flight-mass spectrometry, network pharmacology, and cellular thermal shift assay, phenethyl caffeate and isoliquiritigenin were identified as the potential active compounds in LQHXDW that counteract necroptosis. Based on these observations, we conclude that LQHXDW protects the heart against ischemia or hypoxia-induced cardiac injury and remodeling through suppression of the RIPK1/RIPK3/MLKL pathway-dependent necroptosis and oxidative stress.

Carotid Baroreceptor Stimulation Ameliorates Pulmonary Arterial Remodeling in Rats With Hypoxia-Induced Pulmonary Hypertension.

BACKGROUND: Sympathetic hyperactivity plays an important role in the initiation and maintenance of pulmonary hypertension. Carotid baroreceptor stimulation (CBS) is an effective autonomic neuromodulation therapy. We aim to investigate the effects of CBS on hypoxia-induced pulmonary hypertension and its underlying mechanisms. METHODS AND RESULTS: Rats were randomly assigned into 4 groups, including a Control-sham group (n=7), a Control-CBS group (n=7), a Hypoxia-sham group (n=10) and a Hypoxia-CBS group (n=10). Echocardiography, ECG, and hemodynamics examination were performed. Samples of blood, lung tissue, pulmonary arteries, and right ventricle were collected for the further analysis. In the in vivo study, CBS reduced wall thickness and muscularization degree in pulmonary arterioles, thereby improving pulmonary hemodynamics. Right ventricle hypertrophy, fibrosis and dysfunction were all improved. CBS rebalanced autonomic tone and reduced the density of sympathetic nerves around pulmonary artery trunks and bifurcations. RNA-seq analysis identified BDNF and periostin (POSTN) as key genes involved in hypoxia-induced pulmonary hypertension, and CBS downregulated the mRNA expression of BDNF and POSTN in rat pulmonary arteries. In the in vitro study, norepinephrine was found to promote pulmonary artery smooth muscle cell proliferation while upregulating BDNF and POSTN expression. The proliferative effect was alleviated by silence BDNF or POSTN. CONCLUSIONS: Our results showed that CBS could rebalance autonomic tone, inhibit pulmonary arterial remodeling, and improve pulmonary hemodynamics and right ventricle function, thus delaying hypoxia-induced pulmonary hypertension progression. There may be a reciprocal interaction between POSTN and BDNF that is responsible for the underlying mechanism.

Eleutheroside B Pretreatment Attenuates Hypobaric Hypoxia-Induced High-Altitude Pulmonary Edema by Regulating Autophagic Flux via the AMPK/mTOR Pathway.

High-altitude pulmonary edema (HAPE) is a life-threatening disease, and autophagy deficiency is implicated in the pathogenesis of HAPE. Eleutheroside B (EB), which is the main bioactive component of Acanthopanax senticosus, exhibits various pharmacological activities. Our previous research demonstrated that autophagic structures were widely found in the ultrastructure of lung tissue in HAPE rats. However, whether EB regulates autophagy deficiency in HAPE remains unknown. This study aimed to investigate the protective effects of EB on hypobaric hypoxia-induced HAPE and explore the underlying molecular mechanism of regulating autophagy. The rat model of high-altitude pulmonary edema was replicated using a hypobaric hypoxic chamber. Rats were pretreated with EB or in combination with chloroquine or compound C. The pulmonary edema was assessed by the lung wet/dry ratio, total protein concentration in bronchoalveolar lavage fluid, and histological analysis. Inflammation and oxidative stress were measured using commercial biochemical kits. Autophagy and autophagic flux were evaluated by western blotting, transmission electron microscopy, and adeno-associated virus-mRFP-GFP-labeled tandem fluorescence LC3. The AMPK/mTOR signaling pathway was detected by western blotting. EB alleviated hypobaric hypoxia-induced pulmonary edema, hypoxemia, acid-base imbalance in the blood, inflammation, and oxidative stress in a dose-dependent manner. EB restored impaired autophagic flux by activating the AMPK/mTOR signaling pathway. However, chloroquine or compound C abolished eleutheroside B-mediated autophagy flux restoration. EB has the potential to restore impaired autophagic flux in the lung of hypobaric hypoxia-induced HAPE rats, which could be attributed to the activation of AMPK/mTOR signaling pathway.

Parthenolide attenuates hypoxia-induced pulmonary hypertension through inhibiting STAT3 signaling.

BACKGROUND: Pulmonary hypertension (PH) is a chronic lung disease characterized by the progressive pulmonary vascular remodeling with increased pulmonary arterial pressure and right ventricular failure. Pulmonary vascular remodeling involves the proliferation, migration, and resistance to apoptosis of pulmonary artery smooth cells (PASMCs). Parthenolide (PTN) is a bioactive compound derived from a traditional medical plant feverfew (Tanacetum parthenium), and it has been studied for treatment of pulmonary fibrosis, lung cancer, and other related ailments. However, the function of PTN in the treatment of PH has not been studied. PURPOSE: This study aimed to evaluate the anti-proliferation and pro-apoptosis effects of PTN on PH and investigate its potential mechanisms. METHODS: An in vivo hypoxia-induced pulmonary hypertension (HPH) model was established by maintaining male rats in a hypoxia chamber (10% O2) for 3 weeks, and PTN was intraperitoneally administered at the dose of 10 or 30 mg/kg. We assessed the impact of PTN on mean pulmonary arterial pressure (mPAP), pulmonary vascular remodeling, and right ventricular hypertrophy. In vitro, we evaluated hypoxia-induced cellular proliferation, migration, and apoptosis of rat PASMCs. Proteins related to the STAT3 signaling axis were analyzed by western blotting and immunofluorescence assays. Recovery experiments were performed using the STAT3 activator, colivelin TFA. RESULTS: PTN significantly alleviated the symptoms of HPH rats by attenuating pulmonary arterial remodeling. It also prevented the proliferation and migration of PASMCs. PTN also induced the apoptosis of PASMCs. PTN could directly interact with STAT3 and markedly inhibited STAT3 phosphorylation and nuclear translocation. In vitro, and in vivo experiments demonstrated that overexpression of STAT3 partially suppressed the effect of PTN. CONCLUSION: Our study indicated that PTN alleviated hypoxia-induced pulmonary hypertension in rats by suppressing STAT3 activity.

[Treatment of hypoxia-induced ED in high-altitude areas by transcutaneous low-frequency electrical stimulation based on the parameters obtained from visualized precision electrophysiological diagnosis].

OBJECTIVE: To investigate the effects of visualized precision electrophysiological diagnosis and transcutaneous low-frequency electrical stimulation (TES) on hypoxia-induced ED in high-altitude areas. METHODS: This study included 152 ED patients from high-altitude hypoxic areas treated by TES based on the parameters obtained from visualized precision electrophysiological diagnosis. We followed up the patients for 1 to 3 months and compared their IIEF-5 scores, nocturnal penile tumescence and rigidity (NPTR) and infrared thermal metabolic technology (TMT)-based temperature of the whole body and diseased parts before and after treatment. RESULTS: All the patients successfully completed 1 to 3 courses of TES. There were no statistically significant differences in the IIEF-5 scores (P<0.05) and penile tip optimal erection rigidity and duration (P<0.01) of the patients before and after treatment. TMT images indicated a temperature change of >1.5 ℃ in the penis and bilateral inguinal regions after treatment, suggesting the effectiveness of electrical stimulation. No recurrence was observed during the follow-up. CONCLUSION: TES based on the parameters obtained from visualized precision electrophysiological diagnosis has a definite effect on hypoxia-induced ED by enhancing oxygen supply to the penile corpus cavernosum and improving its function and structure.

Role of the telomeric factor TRF2 in post-hypoxic brain damages.

The neuronal excitotoxicity that follows reoxygenation after a hypoxic period may contribute to epilepsy, Alzheimer's disease, Parkinson's disease and various disorders that are related to inadequate supplement of oxygen in neurons. Therefore, counteracting the deleterious effects of post-hypoxic stress is an interesting strategy to treat a large spectrum of neurodegenerative diseases. Here, we show that the expression of the key telomere protecting protein Trf2 decreases in the brain of mice submitted to a post-hypoxic stress. Moreover, downregulating the expression of Terf2 in hippocampal neural cells of unchallenged mice triggers an excitotoxicity-like phenotype including glutamate overexpression and behavioral alterations while overexpressing Terf2 in hippocampal neural cells of mice subjected to a post-hypoxic treatment prevents brain damages. Moreover, Terf2 overexpression in culture neurons counteracts the oxidative stress triggered by glutamate. Finally, we provide evidence that the effect of Terf2 downregulation on excitotoxicity involves Sirt3 repression leading to mitochondrial dysfunction. We propose that increasing the level of Terf2 expression is a potential strategy to reduce post-hypoxic stress damages.

[Mechanism of Liangfang Wenjing Decoction in treatment of hypoxia on endometriosis with cold coagulation and blood stasis by regulating CHCHD4 expression].

To explore the mechanism of Liangfang Wenjing Decoction regulating coiled-coil-helix coiled-coil-helix domain containing 4(CHCHD4) in the treatment of hypoxia on endometriosis(EMs) with cold coagulation and blood stasis. The rat model of cold coagulation and blood stasis syndrome was prepared by the ice-water bath method, and then the EMs model was established by autologous intimal transplantation. The rats were randomly divided into model group, low, medium, and high(4.7, 9.4, and 18.8 g·kg~(-1)) dose groups of Liangfang Wenjing Decoction, Shaofu Zhuyu Decoction group, and sham group, with 10 rats in each group. The rats were given intragastric administration for four weeks. During the modeling, the general condition and vaginal smear of rats were observed, and the blood flow of ears and uterus were detected by laser speckle contrast imaging(LSCI) to judge the syndrome of cold coagulation and blood stasis. After the administration, the general condition of the rats was observed, and the area of ectopic lesions was measured by caliper. The localization and expression of CHCHD4 and hypoxia inducible factors-1α(HIF-1α) were detected by immunohistochemistry, and the mRNA and protein expressions of CHCHD4 and HIF-1α were detected by real-time quantitative polymerase chain reaction(RT-qPCR) and Western blot. The primary culture of ectopic endometrial stromal cells(ESCs) from EMs patients was performed, and the CHCHD4 overexpression plasmid was constructed and transfected to establish the ESCs model of CHCHD4 overexpression. The cells were divided into the control group, CHCHD4 overexpression group, CHCHD4 overexpression+control serum group, and CHCHD4 overexpression+Liangfang Wenjing Decoction serum group. The protein expression of CHCHD4 and HIF-1α was detected by Western blot, and the glucose consumption and lactic acid level were detected. The cell proliferation was detected by MTT assay. The experiment found that compared with normal rats, the modeling rats showed symptoms of cold coagulation and blood stasis, such as mental malaise, reduced diet and drinking water, disordered estrous cycle, and blocked blood circulation in ears and uterine microvessels. Compared with the sham group, the ectopic lesions in the model group were uplifted, and the mRNA and protein expressions of CHCHD4 and HIF-1α were significantly increased(P<0.05). Compared with the model group, the symptoms of cold coagulation and blood stasis in each treatment group were improved, and the area of ectopic lesions was significantly reduced(P<0.05 or P<0.01). The mRNA and protein expression levels of CHCHD4 and HIF-1α were significantly decreased(P<0.05 or P<0.01). In the cell model, compared with the control group, the expression of CHCHD4, HIF-1α protein, glucose consumption, lactic acid level, and cell proliferation activity in the CHCHD4 overexpression group were significantly increased(P<0.01). Compared with the CHCHD4 overexpression group, there was no significant change in each index in the control serum group, while the protein expression of CHCHD4 and HIF-1α in the Liangfang Wenjing Decoction serum group was decreased significantly(P<0.05 or P<0.01). The glucose consumption, lactic acid level, and cell proliferation activity decreased significantly(P<0.01). It can be seen from the above that the therapeutic effect of Liangfang Wenjing Decoction on EMs with cold coagulation and blood stasis might be related to reducing the expression of CHCHD4 and then improving the hypoxia of ectopic lesions and ectopic ESCs.

[Effect of 2-phenylethyl-beta-glucopyranoside isolated from Huaizhong No. 1 Rehmannia glutinosa on hypoxic pulmonary hypertension by regulating PI3K/Akt/m TOR/HIF-1α pathway].

The study investigated the protective effect and mechanism of 2-phenylethyl-beta-glucopyranoside(Phe) from Huaizhong No.1 Rehmannia glutinosa on hypoxic pulmonary hypertension(PH), aiming to provide a theoretical basis for clinical treatment of PAH. Male C57BL/6N mice were randomly divided into normal group, model group, positive drug(bosentan, 100 mg·kg~(-1)) group, and low-and high-dose Phe groups(20 and 40 mg·kg~(-1)). Except for the normal group, all other groups were continuously subjected to model induction in a 10% hypoxic environment for 5 weeks, with oral administration for 14 days starting from the 3rd week. The cardiopulmonary function, right ventricular pressure, cough and asthma index, lung injury, cell apoptosis, oxidative stress-related indicators, immune cells, and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)/mammalian target of rapamycin(mTOR)/hypoxic inducible factor 1α(HIF-1α) pathway-related proteins or mRNA levels were examined. Furthermore, hypoxia-induced pulmonary arterial smooth muscle cell(PASMC) were used to further explore the mechanism of Phe intervention in PH combined with PI3K ago-nist(740Y-P). The results showed that Phe significantly improved the cardiopulmonary function of mice with PH, decreased right ventricular pressure, cough and asthma index, and lung injury, reduced cell apoptosis, oxidative stress-related indicators, and nuclear levels of phosphorylated Akt(p-Akt) and phosphorylated mTOR(p-mTOR), inhibited the expression levels of HIF-1α and PI3K mRNA and proteins, and maintained the immune cell homeostasis in mice. Further mechanistic studies revealed that Phe significantly reduced the viability and migration ability of hypoxia-induced PASMC, decreased the expression of HIF-1α and PI3K proteins and nuc-lear levels of p-Akt and p-mTOR, and this effect was blocked by 740Y-P. Therefore, it is inferred that Phe may exert anti-PH effects by alleviating the imbalance of oxidative stress and apoptosis in lung tissues and regulating immune levels, and its mechanism may be related to the regulation of the PI3K/Akt/mTOR/HIF-1α pathway. This study is expected to provide drug references and research ideas for the treatment of PH.

MicroRNA-210 mediates hypoxia-induced pulmonary hypertension by targeting mitochondrial bioenergetics and mtROS flux.

AIM: Chronic hypoxia is a common cause of pulmonary hypertension (PH). We test the hypothesis that microRNA-210 (miR-210) mediates hypoxia-induced PH by targeting mitochondrial metabolism and increasing reactive oxygen species (mtROS) production in the lungs. METHODS: Adult wildtype (WT) or miR-210 knockout (KO) mice were exposed to hypoxia (10.5% O2) or normoxia for 4 weeks. We measured miR-210 levels, right ventricular systolic pressure (RVSP), and histological changes in heart and lung tissues. Mitochondrial bioenergetics and mtROS production were assessed in isolated lung mitochondria. RESULTS: Hypoxia increased right ventricular wall thickness and pulmonary vessel wall muscularization in WT, but not miR-210 KO mice. No sex differences were observed. In male mice, hypoxia increased miR-210 levels in the lung and RVSP, which were abrogated by miR-210 deficiency. Hypoxia upregulated mitochondrial oxygen consumption rate and mtROS flux, which were negated in miR-210 KO animals. In addition, chronic hypoxia increased macrophage accumulation in lungs of WT, but not miR-210 KO mice. Moreover, miR-210 overexpression in lungs of WT animals recapitulated the effects of hypoxia and increased mitochondrial oxygen consumption rate, mtROS flux, right ventricular wall thickness, pulmonary vessel wall muscularization and RVSP. MitoQ revoked the effects of miR-210 on lung mitochondrial bioenergetics, right ventricular and pulmonary vessel remodeling and RVSP. CONCLUSION: Our findings with loss-of-function and gain-of-function approaches provide explicit evidence that miR-210 mediates hypoxia-induced PH by upregulating mitochondrial bioenergetics and mtROS production in a murine model, revealing new insights into the mechanisms and therapeutic targets for treatment of PH.

Adding a sustained attention task to a physically demanding cycling exercise exacerbates neuromuscular fatigue and impairs cognitive performance in both normoxia and hypoxia.

PURPOSE: Both cognitive motor dual-tasks (CMDT) protocols and hypoxic environments have been associated with significant impairments in cognitive and physical performance. We aimed to determine the effects of hypoxia on cognitive performance and neuromuscular fatigue during a highly physically demanding CMDT. METHODS: Fifteen young adults completed a first session involving a cognitive task (CTLCOG) followed by cycling exercise (CTLEX) in normoxia. After that, they randomly participated in CMDT sessions in normoxia (DTNOR) and hypoxia (DTHYP). The physical exercise consisted of 20 min cycling at a "hard" perceived effort, and the cognitive task consisted of 15 min sustained attention to response time task (SART). Concurrent psycho-physiological measurements included: quadriceps neuromuscular fatigue (peripheral/central components from femoral nerve electrostimulation), prefrontal cortex (PFC) oxygenation by near-infrared spectroscopy, and perception of effort. RESULTS: SART performance significantly decreased in DTNOR (-15.7 ± 15.6%, P < 0.01) and DTHYP (-26.2 ± 16.0%, P < 0.01) compared to CTLCOG (-1.0 ± 17.7%, P = 0.61). Peripheral fatigue similarly increased across conditions, whereas the ability of the central nervous system to activate the working muscles was impaired similarly in DTNOR (-6.1 ± 5.9%, P < 0.001) and DTHYP (-5.4 ± 7.3%, P < 0.001) compared to CTLEX (-1.1 ± 0.2%, P = 0.52). Exercise-induced perception of effort was higher in DTHYP vs. DTNOR and in DTNOR vs. CTLEX. This was correlated with cognitive impairments in both normoxia and hypoxia. PFC deoxygenation was more pronounced in DTHYP compared to DTNOR and CTLEX. CONCLUSION: In conclusion, performing a sustained attention task together with physically challenging cycling exercise promotes central neuromuscular fatigue and impairs cognitive accuracy; the latter is particularly noticeable when the CMDT is performed in hypoxia.

[Effects and mechanisms of Gegen Qinlian Decoction in inhibiting M1 polarization of macrophages under inflammatory hypoxia microenvironment].

To explore the effect and mechanism of Gegen Qinlian Decoction(GQD) in inhibiting M1 polarization of macrophages under inflammatory hypoxia by simulating intestinal hypoxia microenvironment in vitro. A tri-gas incubator was used to simulate normal physiological hypoxia of the colon and inflammatory hypoxia microenvironments of ulcerative colitis(UC). RAW264.7 macrophages were divided into 18.5% O_(2 )(normoxia group), 4% O_2(physiological hypoxia group), and 1% O_2(inflammatory hypoxia group), and they were induced by lipopolysaccharide(LPS) for 24 h. M1 polarization was detected by flow cytometry. Under the condition of 1% inflammatory hypoxia, they were divided into blank group, model group, and GQD-containing serum low, medium, and high dose groups. Flow cytometry was used to detect M1 polarization marker CD86, and ELISA was used to detect the expression of tumor necrosis factor-α(TNF-α) and interleukin-1ß(IL-1ß) in cell supernatant. The mRNA expression of hypoxia-inducible factor-1α(HIF-1α), TNF-α, and IL-1ß was detected by qRT-PCR. Western blot was used to detect the expression of HIF-1α/nuclear transcription factor-κB(NF-κB) signaling pathway-related proteins. The nuclear translocation of NF-κB p65 was detected by immunofluorescence. The results showed that the positive rate of CD86 in the 1% O_2 group was the highest. Under the condition of 1% inflammatory hypoxia, compared with the blank group, the expression of CD86, TNF-α, IL-1ß, and HIF-1α in the model group increased. Compared with the model group, each group of GQD could reduce the expression of CD86, TNF-α, IL-1ß, and HIF-1α. Compared with the blank group, the protein expression of HIF-1α, NF-κB p65, p-IKKα/ß, and p-IκBα in the model group increased. Compared with the model group, the protein expression of HIF-1α, NF-κB p65, p-IKKα/ß, and p-IκBα in GQD groups was significantly decreased. Compared with the blank group, NF-κB p65 in the model group entered the nucleus significantly. Compared with the model group, the nuclear expression of NF-κB p65 was decreased in each GQD group. Studies have shown that GQD may protect the intestine by down-regulating the HIF-1α/NF-κB signaling pathway to inhibit M1 polarization of macrophages and secretion of related inflammatory factors under 1% inflammatory hypoxia.

Reversal of cerebral ischaemia and hypoxia and of sickness behaviour by megadose sodium ascorbate in ovine Gram-negative sepsis.

BACKGROUND: The mechanisms by which megadose sodium ascorbate improves clinical status in experimental sepsis is unclear. We determined its effects on cerebral perfusion, oxygenation, and temperature, and plasma levels of inflammatory biomarkers, nitrates, nitrites, and ascorbate in ovine Gram-negative sepsis. METHODS: Sepsis was induced by i.v. infusion of live Escherichia coli for 31 h in unanaesthetised Merino ewes instrumented with a combination sensor in the frontal cerebral cortex to measure tissue perfusion, oxygenation, and temperature. Fluid resuscitation at 23 h was followed by i.v. megadose sodium ascorbate (0.5 g kg-1 over 30 min+0.5 g kg-1 h-1 for 6.5 h) or vehicle (n=6 per group). Norepinephrine was titrated to restore mean arterial pressure (MAP) to 70-80 mm Hg. RESULTS: At 23 h of sepsis, MAP (mean [sem]: 85 [2] to 64 [2] mm Hg) and plasma ascorbate (27 [2] to 15 [1] µM) decreased (both P<0.001). Cerebral ischaemia (901 [58] to 396 [40] units), hypoxia (34 [1] to 19 [3] mm Hg), and hyperthermia (39.5 [0.1]°C to 40.8 [0.1]°C) (all P<0.001) developed, accompanied by malaise and lethargy. Sodium ascorbate restored cerebral perfusion (703 [121] units], oxygenation (30 [2] mm Hg), temperature (39.2 [0.1]°C) (all PTreatment<0.05), and the behavioural state to normal. Sodium ascorbate slightly reduced the sepsis-induced increase in interleukin-6, returned VEGF-A to normal (both PGroupxTime<0.01), and increased plasma ascorbate (20 000 [300] µM; PGroup<0.001). The effects of sodium ascorbate were not reproduced by equimolar sodium bicarbonate. CONCLUSIONS: Megadose sodium ascorbate rapidly reversed sepsis-induced cerebral ischaemia, hypoxia, hyperthermia, and sickness behaviour. These effects were not reproduced by an equimolar sodium load.

Hyperoxic recovery interferes with the metabolic imprint of hypoxic exercise.

Supplemental oxygen (hyperoxia) improves physical performance during hypoxic exercise. Based on the analysis of metabolome and iron homeostasis from human athlete blood samples, we show that hyperoxia during recovery periods interferes with metabolic alterations following hypoxic exercise. This may impair beneficial adaptations to exercise and/or hypoxia and highlights risks of oxygen supplementation in hypoxia.

Beetroot in deep waters: Navigating the risks of supplement-induced blackouts in aquatic training.

Beetroot powder, a popular athletic supplement high in nitrates, purportedly enhances exercise performance. However, recent incidents during breath-hold swims in Air Force Special Warfare training, associated with beetroot powder use, raise safety concerns. Two cases of hypoxic events prompt discussion on interactions between beetroot supplementation and cardiovascular responses to breath-hold diving, suggesting a risk for blackout. Beetroot-induced vasodilation may counteract normal cardiovascular responses during swimming, emphasizing the need for further research to quantify risks. With inconsistent dosing and lack of standardized recommendations, heightened awareness of these risks is crucial for informed decision-making regarding beetroot supplements, especially in tactical athletes.

Combining Neuromodulation Strategies in Spinal Cord Injury Gait Rehabilitation: A Proof of Concept, Randomized, Crossover Trial.

OBJECTIVES: To evaluate if acute intermittent hypoxia (AIH) coupled with transcutaneous spinal cord stimulation (tSCS) enhances task-specific training and leads to superior and more sustained gait improvements as compared with each of these strategies used in isolation in persons with chronic, incomplete spinal cord injury. DESIGN: Proof of concept, randomized crossover trial. SETTING: Outpatient, rehabilitation hospital. INTERVENTIONS: Ten participants completed 3 intervention arms: (1) AIH, tSCS, and gait training (AIH + tSCS); (2) tSCS plus gait training (SHAM AIH + tSCS); and (3) gait training alone (SHAM + SHAM). Each arm consisted of 5 consecutive days of intervention with a minimum of a 4-week washout between arms. The order of arms was randomized. The study took place from December 3, 2020, to January 4, 2023. MAIN OUTCOME MEASURES: 10-meter walk test at self-selected velocity (SSV) and fast velocity, 6-minute walk test, timed Up and Go (TUG) and secondary outcome measures included isometric ankle plantarflexion and dorsiflexion torque RESULTS: TUG improvements were 3.44 seconds (95% CI: 1.24-5.65) significantly greater in the AIH + tSCS arm than the SHAM AIH + tSCS arm at post-intervention (POST), and 3.31 seconds (95% CI: 1.03-5.58) greater than the SHAM + SHAM arm at 1-week follow up (1WK). SSV was 0.08 m/s (95% CI: 0.02-0.14) significantly greater following the AIH + tSCS arm than the SHAM AIH + tSCS at POST. Although not significant, the AIH + tSCS arm also demonstrated the greatest average improvements compared with the other 2 arms at POST and 1WK for the 6-minute walk test, fast velocity, and ankle plantarflexion torque. CONCLUSIONS: This pilot study is the first to demonstrate that combining these 3 neuromodulation strategies leads to superior improvements in the TUG and SSV for individuals with chronic incomplete spinal cord injury and warrants further investigation.

Ferroptosis pathways: Unveiling the neuroprotective power of cistache deserticola phenylethanoid glycosides.

ETHNOPHARMACOLOGICAL RELEVANCE: Cistanche deserticola is a kind of parasitic plant living in the roots of desert trees. It is a rare Chinese medicine, which has the effect of tonifying kidney Yang, benefiting essence and blood and moistening the intestinal tract. Cistache deserticola phenylethanoid glycoside (PGS), an active component found in Cistanche deserticola Ma, have potential kidney tonifying, intellectual enhancing, and neuroprotective effects. Cistanche total glycoside capsule has been marketed to treat vascular dementia disease. AIM OF THE STUDY: To identify the potential renal, intellectual enhancing and neuroprotective effects of PGS and explore the exact targets and mechanisms of PGS. MATERIALS AND METHODS: This study systematically investigated the four types of pathways leading to ferroptosis through transcriptome, metabolome, ultrastructure and molecular biology techniques and explored the molecular mechanism by which multiple PGS targets and pathways synergistically exert neuroprotective effects on hypoxia. RESULTS: PGS alleviated learning and memory dysfunction and pathological injury in mice exposed to hypobaric hypoxia by attenuating hypobaric hypoxia-induced hippocampal histopathological damage, impairing blood‒brain barrier integrity, increasing oxidative stress levels, and increasing the expression of cognitive proteins. PGS reduced the formation of lipid peroxides and improved ferroptosis by upregulating the GPX-4/SCL7A311 axis and downregulating the ACSL4/LPCAT3/LOX axis. PGS also reduced ferroptosis by facilitating cellular Fe2+ efflux and regulating mitochondrial Fe2+ transport and effectively antagonized cell ferroptosis induced by erastin (a ferroptosis inducer). CONCLUSIONS: This study demonstrated the mechanism by which PGS prevents hypobaric hypoxic nerve injury through four types of ferroptosis pathways, achieved neuroprotective effects and alleviated learning and memory dysfunction in hypobaric hypoxia mice. This study provides a theoretical basis for the development and application of PGS.

The effects of MEPaL on oxidative stress and motor function in the rats affected by prenatal hypoxia.

BACKGROUND AND OBJECTIVES: Maternal hypoxia disrupts neural development and subsequently leads to cerebral palsy and epilepsy in newborns. Hypoxia plays a role in neurodegeneration by increasing oxidative stress. Pistacia atlantica is known as an important antioxidant, and its anti-inflammatory and antioxidant effects have been shown in various studies. This study aims to investigate the effects of methanolic extract of P. atlantica leaves (MEPaLs) on the oxidative parameters in the serum of rats affected by maternal hypoxia. MATERIAL AND METHODS: In this study, eight pregnant rats were used. The newborns were divided into four groups, including the control and the hypoxia groups, which are affected by maternal hypoxia, hypoxia + MEPaL 100 mg/kg, and hypoxia + MEPaL 150 mg/kg. MEPaL was injected (i.p) for 21 days into the neonatal rats after the lactation period. Hypoxia was induced by keeping pregnant rats in a hypoxic chamber with 7% oxygen and 93% nitrogen intensity for 3 h on the 20th day of pregnancy. Behavioral changes were measured using open-field and rotarod tests. Finally, biomarkers of oxidative stress, nitric oxide (NO), glutathione (GSH), GSSG, TAS, TOS, and oxidative stress index (OSI) were measured in the experimental groups. RESULTS: Behavioral results showed that the anxiety behavior in the hypoxia group increased, but the motor activity (moved distance and movement speed) decreased. Moreover, the amount of time spent maintaining balance on the rotarod rod was significantly decreased in the hypoxia group. The concentration of NO in the group of hypoxia + MEPaL 100 mg/kg showed a significant decrease, and MEPaL 100, and 150 mg/kg + hypoxia also increased the concentration of GSH and decreased GSSG. In addition, MEPaL100 and 150 mg/kg caused a significant increase in the ratio of GSH to GSSG and decreased OSI and total oxidant capacity. CONCLUSIONS: Oxidative stress increased in the rats affected by maternal hypoxia and may be the main mechanism for motor activity impairment and balance disturbance, whereas MELaL improved motor performance by decreasing oxidative stress.

Intermittent hypoxia training enhances Aß endocytosis by plaque associated microglia via VPS35-dependent TREM2 recycling in murine Alzheimer's disease.

BACKGROUND: Beta-amyloid (Aß) deposition in the brain parenchyma is a crucial initiating step in the amyloid cascade hypothesis of Alzheimer's disease (AD) pathology. Furthermore, dysfunction of plaque-associated microglia, also known as disease-associated microglia (DAM) has been reported to accelerate Aß deposition and cognitive impairment. Our previous research demonstrated that intermittent hypoxia training (IHT) improved AD pathology by upregulating autophagy in DAM, thereby enhancing oligomeric Aß (oAß) clearance. Considering that oAß internalization is the initial stage of oAß clearance, this study focused on the IHT mechanism involved in upregulating Aß uptake by DAM. METHODS: IHT was administered to 8-month-old APP/PS1 mice or 6-month-old microglial vacuolar protein sorting 35 (VPS35) knockout mice in APP/PS1 background (MG VPS35 KO: APP/PS1) for 28 days. After the IHT, the spatial learning-memory capacity of the mice was assessed. Additionally, AD pathology was determined by estimating the nerve fiber and synapse density, Aß plaque deposition, and Aß load in the brain. A model of Aß-exposed microglia was constructed and treated with IHT to explore the related mechanism. Finally, triggering receptor expressed on myeloid cells 2 (TREM2) intracellular recycling and Aß internalization were measured using a fluorescence tracing technique. RESULTS: Our results showed that IHT ameliorated cognitive function and Aß pathology. In particular, IHT enhanced Aß endocytosis by augmenting the intracellular transport function of microglial TREM2, thereby contributing to Aß clearance. Furthermore, IHT specifically upregulated VPS35 in DAM, the primary cause for the enhanced intracellular recycling of TREM2. IHT lost ameliorative effect on Aß pathology in MG VPS35 KO: APP/PS1 mice brain. Lastly, the IHT mechanism of VPS35 upregulation in DAM was mediated by the transcriptional regulation of VPS35 by transcription factor EB (TFEB). CONCLUSION: IHT enhances Aß endocytosis in DAM by upregulating VPS35-dependent TREM2 recycling, thereby facilitating oAß clearance and mitigation of Aß pathology. Moreover, the transcriptional regulation of VPS35 by TFEB demonstrates a close link between endocytosis and autophagy in microglia. Our study further elucidates the IHT mechanism in improving AD pathology and provides evidence supporting the potential application of IHT as a complementary therapy for AD.

Luteolin ameliorates hypoxic pulmonary vascular remodeling in rat via upregulating KV1.5 of pulmonary artery smooth muscle cells.

BACKGROUND: Hypoxic pulmonary vascular remodeling (HPVR) is a key pathological feature of hypoxic pulmonary hypertension (HPH). Oxygen-sensitive potassium (K+) channels in pulmonary artery smooth muscle cells (PASMCs) play a crucial role in HPVR. Luteolin (Lut) is a plant-derived flavonoid compound with variety of pharmacological actions. Our previous study found Lut alleviated HPVR in HPH rat. PURPOSE: To elucidate the mechanism by which Lut mitigated HPVR, focusing on oxygen-sensitive voltage-dependent potassium channel 1.5 (Kv1.5). METHODS: HPH rat model was established using hypobaric chamber to simulate 5000 m altitude. Isolated perfused/ventilated rat lung, isolated pulmonary arteriole ring was utilized to investigate the impact of Lut on K+ channels activity. Kv1.5 level in lung tissue and pulmonary arteriole of HPH rat was assessed. CyclinD1, CDK4, PCNA, Bax, Bcl-2, cleaved caspase-3 levels in lung tissue of HPH rat were tested. The effect of Lut on Kv1.5, cytoplasmic free calcium concentration ([Ca2+]cyt), CyclinD1, CDK4, PCNA, Bax/Bcl-2 was examined in PASMCs under hypoxia, with DPO-1 as a Kv1.5 specific inhibitor. The binding affinity between Lut and Kv1.5 in PASMCs was detected by drug affinity responsive target stability (DARTS). The overexpression of KCNA5 gene (encoding Kv1.5) in HEK293T cells was utilized to confirm the interaction between Lut and Kv1.5. Furthermore, the impact of Lut on mitochondrial structure, SOD, GSH, GSH-Px, MDA and HIF-1α levels were evaluated in lung tissue of HPH rat and PASMCs under hypoxia. RESULTS: Lut dilated pulmonary artery by directly activating Kv and Ca2+-activated K+ channels (KCa) in smooth muscle. Kv1.5 level in lung tissue and pulmonary arteriole of HPH rat was upregulated by Lut. Lut downregulated CyclinD1, CDK4, PCNA while upregulating Bax/Bcl-2/caspase-3 axis in lung tissue of HPH rat. Lut decreased [Ca2+]cyt, reduced CDK4, CyclinD1, PCNA, increased Bax/Bcl-2 ratio, in PASMCs under hypoxia, by upregulating Kv1.5. The binding affinity and the interaction between Lut and Kv1.5 was verified in PASMCs and in HEK293T cells. Lut also decreased [Ca2+]cyt and inhibited proliferation via targeting Kv1.5 of HEK293T cells under hypoxia. Furthermore, Lut protected mitochondrial structure, increased SOD, GSH, GSH-Px, decreased MDA, in lung tissue of HPH rat. Lut downregulated HIF-1α level in both lung tissue of HPH rat and PASMCs under hypoxia. CONCLUSION: Lut alleviated HPVR by promoting vasodilation of pulmonary artery, reducing cellular proliferation, and inducing apoptosis through upregulating of Kv1.5 in PASMCs.