OBJECTIVES: To investigate the targets and mechanisms of 7-hydroxyethyl chrysin (7-HEC) in prevention and treatment of high-altitude cerebral edema (HACE) in rats. METHODS: Fifty-four male Wistar rats were randomly divided into normal control group, HACE model group, and 7-HEC-treated group (18 rats in each group). Except for the normal control group, rats in the two other groups were exposed to a hypobaric hypoxic chamber simulating a 7000 m altitude for 72 h to establish the HACE model. The 7-HEC-treated group was intraperitoneally injected with 7-HEC (150 mg·kg^－¹·d^－¹) for 3 consecutive days before modeling, while the model group received equivalent isotonic sodium chloride solution. Tandem Mass Tag (TMT) proteomics technology was used to detect differentially expressed proteins (DEPs) with screening criteria set at a fold change >1.2 and P<0.05. Western blotting was used to verify the expression levels of target proteins. Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein-protein interaction (PPI) network analysis were performed. RESULTS: Compared with the normal control group, 256 DEPs were identified in the HACE model group. Compared with the HACE model group, 87 DEPs were identified in the 7-HEC-treated group. Among them, 19 DEPs that were dysregulated in the HACE model group were restored after 7-HEC intervention, of which seven (HSPA4, Arhgap20, SERT, HACL1, CCDC43, POLR3A, and PCBD1) were confirmed by Western blotting. GO enrichment analysis of the DEPs between the HACE model and 7-HEC-treated groups revealed their involvement in 13 biological processes, five cellular components, and two molecular functions. KEGG pathway analysis indicated associations with the mRNA surveillance pathway, Th17 cell differentiation, serotonergic synapse, RNA polymerase, protein processing in the endoplasmic reticulum, peroxisome, neuroactive ligand-receptor interaction, folate biosynthesis. PPI network analysis demonstrated that HSPA4, POLR3A, and HACL1, which were validated by Western blotting, interacted with multiple signaling pathways and ranked among the top 20 hub proteins by degree value, suggesting their potential role as core regulatory factors. Arhgap20, SERT and PCBD1 also exhibited interactions with several proteins, suggesting their potential as key regulatory proteins, whereas no interactions for CCDC43 were identified. CONCLUSIONS This study applied TMT proteomics to identify seven potential therapeutic targets of 7-HEC for the prevention and treatment of HACE. These targets may be involved in the pathogenesis of HACE through multiple pathways, including maintaining cellular homeostasis, ameliorating oxidative stress, regulating energy metabolism, and reducing vascular permeability.
Animals ; Male ; Proteomics/methods* ; Rats, Wistar ; Flavonoids/therapeutic use* ; Rats ; Brain Edema/etiology* ; Altitude Sickness/metabolism* ; Protein Interaction Maps

OBJECTIVE: To investigate the whole-genome differential methylation profile of patients with high-altitude polycythemia (HAPC). METHODS: In this study, a total of 20 adult male patients with HAPC were included, including 10 Tibetan and 10 Han patients. The control group consisted of 20 healthy adult males, including 10 Tibetan and 10 Han patients. Peripheral blood was collected from each group for DNA extraction and quality inspection, and DNA libraries were constructed. The differential methylation regions (DMRs) between groups were detected using reduced representation bisulfite sequencing, with enriched regions compared to those of the control group. The differential enrichment regions were selected, and the intersection of the enriched regions was associated with genes. The methylation enrichment regions that differed significantly between groups were filtered based on the number of enriched samples in the enriched regions between the groups. GO, KEGG functional, and pathway analysis were performed on the differentially associated gene sets to reveal significant differences between the patients and control groups at the functional and pathway levels. RESULTS: In comparison with the control group, 17 152 sites with more than 25% difference and 15 558 sites with less than -25% difference were identified in Tibetan patients. The top 5 genes with the largest methylation differences between the two groups were MCCC2, RP3-399L15.3, ZNF621, RP11-394A14.2 and SLC39A10. The top significantly different pathways annotated in the differentially expressed genes pathway was serotonergic synapse. In comparison with the control group, 2 687 CpG sites with a greater than 25% difference and 2 602 CpG sites with a less than -25% difference were identified in Han patients. The top 5 genes with the largest methylation differences between the two groups were NAA25, CORO2B, PDC, ZNF853, and MLLT10. The top significantly different pathways annotated in the differentially expressed genes pathway were glutamatergic synapse, retrograde endocannabinoid signaling, Rap1 signaling pathway and cholinergic synapse. In comparison with the control group, 3 895 CpG sites with a greater than 25% difference and 3 969 CpG sites with a less than -25% difference were identified in HAPC patients. The maximum methylation difference between the two groups could reach 78.1%, while the minimum was -42.6%. The top 5 genes with the largest methylation differences between the two groups were MCCC2, ARSJ, CTNNA3, SLC39A10, and SWAP70. The top significantly different pathways annotated in the differentially expressed genes pathway was signaling pathways regulating pluripotency of stem cells. CONCLUSION The occurrence of HAPC may be related to abnormal changes in DNA methylation, and methylation sites may be helpful for the early diagnosis of HAPC.
Humans ; DNA Methylation ; Altitude ; Polycythemia/genetics* ; Male ; Adult ; CpG Islands

OBJECTIVE: High-altitude hypoxia exposure often damages hippocampus-dependent learning and memory. Nogo-A is an important axonal growth inhibitory factor. However, its function in high-altitude hypoxia and its mechanism of action remain unclear. METHODS: In an in vivo study, a low-pressure oxygen chamber was used to simulate high-altitude hypoxia, and genetic or pharmacological intervention was used to block the Nogo-A/NgR1 signaling pathway. Contextual fear conditioning and Morris water maze behavioral tests were used to assess learning and memory in rats, and synaptic damage in the hippocampus and changes in oxidative stress levels were observed. In vitro, SH-SY5Y cells were used to assess oxidative stress and mitochondrial function with or without Nogo-A knockdown in Oxygen Glucose-Deprivation/Reperfusion (OGD/R) models. RESULTS: Exposure to acute high-altitude hypoxia for 3 or 7 days impaired learning and memory in rats, triggered oxidative stress in the hippocampal tissue, and reduced the dendritic spine density of hippocampal neurons. Blocking the Nogo-A/NgR1 pathway ameliorated oxidative stress, synaptic damage, and the learning and memory impairment induced by high-altitude exposure. CONCLUSION: Our results demonstrate the detrimental role of Nogo-A protein in mediating learning and memory impairment under high-altitude hypoxia and suggest the potential of the Nogo-A/NgR1 signaling pathway as a crucial therapeutic target for alleviating learning and memory dysfunction induced by high-altitude exposure. GRAPHICAL ABSTRACT available in www.besjournal.com.
Animals ; Oxidative Stress ; Hippocampus/metabolism* ; Rats ; Nogo Proteins/genetics* ; Male ; Rats, Sprague-Dawley ; Hypoxia/metabolism* ; Altitude ; Synapses ; Humans ; Altitude Sickness/metabolism*

Objective To evaluate the value of pre-ascent 6-minute walking test performed at a high altitude in predicting the incidence of acute mountain sickness(AMS)induced by rapid ascent to a very high altitude.Methods After baseline information was collected,participants completed the 6-minute walking test at a high altitude of 2 900 m.Then,they rapidly ascended to a very high altitude of 5 000 m.The Lake Louise score was recorded to assess AMS.Results The AMS group showed a shorter pre-ascent 6-minute walking distance(6MWD)at the high altitude than the non-AMS group[480.00(450.00,521.75)m vs.546.00(516.50,568.50)m,P=0.006].No difference was observed regarding the pre-ascent heart rate or peripheral oxygen saturation(both P>0.05).The pre-ascent 6MWD at the high altitude was negatively correlated with the Lake Louise score assessed after rapid ascent to the very high altitude(r=-0.497,P=0.012).Logistic regression analysis confirmed that the pre-ascent 6MWD at the high altitude was associated with the risk of AMS induced by rapid ascent to the very high altitude(OR=0.971,95% CI=0.947-0.996,P=0.022).The results indicated that the pre-ascent 6MWD demonstrated ideal prediction performance(area under receiver operating characteristic curve=0.846,P=0.006).Conclusion The pre-ascent 6MWD recorded at the high altitude is a convenient and reliable predictor of the AMS induced by rapid ascent to the very high altitude.
Humans ; Altitude Sickness/diagnosis* ; Male ; Adult ; Female ; Young Adult ; Middle Aged ; Acute Disease ; Walk Test ; Walking ; Altitude ; Exercise Test

Objective: To explore the associations of glycated hemoglobin (HbA1c) with FPG and oral glucose tolerance test 2-hour (OGTT-2 h) in areas at different altitude in China. Methods: Subjects who participated in 2018-2019 China Chronic Disease and Risk Factor Surveillance and had no prior type 2 diabetes diagnosis were included. Subsequently, they were categorized into three groups based on altitude of living area (<2 000, 2 000- and ≥3 000 m). With adjustment for intracluster correlation, multivariable linear regression analysis was performed to evaluate the associations of HbA1c with FPG and OGTT-2 h in the context of HbA1c was normal (<5.7%) or abnormal (≥5.7%). Furthermore, the shape of relationships between HbA1c and glucose indicators was examined using restricted cubic spline. Finally, receiver operating characteristic curve was used to evaluate the diagnostic performance of HbA1c for diabetes. Results: A total of 157 277 subjects were included in the analysis. While FPG and OGTT-2 h levels gradually decreased with increase of altitude, HbA1c level was similar among the three groups. When HbA1c was <5.7%, its association with FPG and OGTT-2 h was weak and no obvious difference was observed among the three groups. When HbA1c was ≥5.7%, the FPG and OGTT-2 h increased by 15.45% (95%CI:14.71%- 16.18%) and 24.54% (95%CI:23.18%-25.91%) respectively per one standard deviation increase in HbA1c in group in area at altitude <2 000 m. However, the FPG and OGTT-2 h increased by 13.08% (95%CI:10.46%-15.76%) and 21.72% (95%CI:16.39%-27.31%), respectively, in group in area at altitude 2 000- m, and increased by 11.41% (95%CI:9.32%-13.53%) and 20.03% (95%CI:15.38%- 24.86%), respectively, in group of altitude ≥3 000 m. The restricted cubic spline indicated that the curve showing the association of HbA1c with FPG and OGTT-2 h was flat when HbA1c was <5.7%, but showed a positive linear relationship when HbA1c was ≥5.7%. The area under curve for detecting diabetes was 0.808 (95%CI:0.803-0.812) in group of altitude <2 000 m and 0.728 (95%CI:0.660-0.796, P=0.022) in group of altitude ≥3 000 m. The relevant optimal cutoff value of HbA1c was 5.7%, with a sensitivity of 65.4% and a specificity of 83.0%, and 6.0%, with a sensitivity of 48.3% and a specificity of 93.7%, respectively. Conclusions: When HbA1c was ≥5.7%, the association between HbA1c and glucose indicators became weaker as the increase of altitude. In the area at altitude ≥3 000 m, it may not be appropriate to use HbA1c in the diagnosis of diabetes.
Adult ; Humans ; Glycated Hemoglobin ; Diabetes Mellitus, Type 2/diagnosis* ; Blood Glucose/analysis* ; Glucose ; Altitude ; Fasting ; China/epidemiology* ; Diabetes Mellitus/epidemiology*

The plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzoniae) are native species unique to the Qinghai-Tibetan Plateau with successful adaptation to the hypoxic environment. In this study, the number of red blood cells, hemoglobin concentration, mean hematocrit and mean volume of red blood cells were measured in plateau zokors and plateau pikas at different altitudes. Hemoglobin subtypes of two plateau animals were identified by mass spectrometry sequencing. The forward selection sites in two animals' hemoglobin subunits were analyzed by PAML4.8 program. Homologous modeling was used to analyze the effect of forward selection sites on the affinity of hemoglobin to oxygen. The adapting strategies of plateau zokors and plateau pikas to hypoxia at different altitudes were analyzed through comparing blood parameters between the two species. The results indicated that, with increasing altitudes, plateau zokors responded to hypoxia by increasing red blood cell count and decreasing red blood cell volume, while plateau pikas took the opposite strategies to plateau zokors. In erythrocytes of plateau pikas, both adult α₂β₂ and fetal α₂ε₂ hemoglobins were identified, while erythrocytes of plateau zokors only had adult α₂β₂ hemoglobin, however the affinities and the allosteric effects of the hemoglobin of plateau zokors were significantly higher than those of plateau pikas. Mechanistically, in the α and β subunits of hemoglobin of plateau zokors and pikas, the numbers and the sites of the positively selected amino acids as well as the side chain groups polarities and orientations of the amino acids differed significantly, which may result in the difference of the affinities to oxygen of hemoglobin between plateau zokors and pikas. In conclusion, the adaptive mechanisms to respond to hypoxia in blood properties of plateau zokors and plateau pikas are species-specific.
Animals ; Altitude ; Amino Acids ; Hemoglobins ; Hypoxia ; Lagomorpha

The alteration of pulmonary artery pressure is an important physiological indicator to reflect the organism's adaptation to acclimatization or the pathological injury in response to high-altitude hypoxic environment. The effects of hypoxic stress at different altitudes for different time on pulmonary artery pressure are different. There are many factors involved in the changes of pulmonary artery pressure, such as the contraction of pulmonary arterial smooth muscle, hemodynamic changes, abnormal regulation of vascular activity and abnormal changes of cardiopulmonary function. Understanding of the regulatory factors of pulmonary artery pressure in hypoxic environment is crucial in clarifying the relevant mechanisms of hypoxic adaptation, acclimatization, prevention, diagnosis, treatment and prognosis of acute and chronic high-altitude diseases. In recent years, great progress has been made in the study regarding the factors affecting pulmonary artery pressure in response to high-altitude hypoxic stress. In this review, we discuss the regulatory factors and intervention measures of pulmonary arterial hypertension induced by hypoxia from the aspects of hemodynamics of circulatory system, vasoactive state and changes of cardiopulmonary function.
Humans ; Altitude ; Arterial Pressure ; Acclimatization ; Hypoxia ; Muscle, Smooth

OBJECTIVE: To explore the pathogenesis of erythrocytosis by detecting the key enzymes of glucose metabolism and glucose transporter in bone marrow erythrocytes of chronic mountain sickness (CMS), and analyzing its correlation with hemoglobin. METHODS: Twenty CMS patients hospitalized in Qinghai Provincial People's Hospital from January 2019 to December 2020 were selected as CMS group. Twenty males with leukocyte count > 3.5×10⁹/L who had accepted bone marrow aspiration and had normal result were taken as control group. The mRNA and protein expression of key enzymes and glucose transporter in glucose metabolism in bone marrow CD71⁺ erythrocytes were detected by real time qPCR and Western blot, respectively. Glucose, lactic acid and 2,3-diphosphoglycerate in the bone marrow supernatant and serum were tested by ELISA. The mRNA and protein expression of key enzymes and glucose transporter, glucose, lactic acid and 2,3-diphosphoglycerate of the two groups were compared. Pearson correlation was used to analyze the correlation between key enzymes, glucose transporter in glucose metabolism in bone marrow CD71⁺ erythrocytes and hemoglobin. RESULTS: The expression of HK2, GLUT1 and GLUT2 mRNA in the CMS group were higher than those in the control group (P<0.001), while the expression of HK1, OGDH and COX5B mRNA were not different. The expression of HK2, GLUT1 and GLUT2 protein in the CMS group were higher than those in the control group (P<0.05). The levels of glucose and lactic acid in the bone marrow supernatant and serum in the CMS group were not different from those in the control group, while the level of 2,3-diphosphoglycerate was higher (P<0.001). Both HK2 and GLUT2 proteins were positively correlated with hemoglobin (r=0.511, 0.717). CONCLUSION CMS patients may increase glycolysis by increasing the expression of HK2, and promote the utilization of glucose through high expression of GLUT1 and GLUT2 to meet the need of energy supply.
Male ; Humans ; Altitude Sickness/metabolism* ; Glucose Transporter Type 1 ; 2,3-Diphosphoglycerate ; Hemoglobins ; Chronic Disease ; RNA, Messenger ; Phenotype ; Glucose

OBJECTIVE: To explore the protective effect and possible mechanisms of bloodletting acupuncture at Jing-well points (BAJP) pre-treatment on acute hypobaric hypoxia (AHH)-induced myocardium injury rat. METHODS: Seventy-five rats were randomly divided into 5 groups by a random number table: a control group (n=15), a model group (n=15), a BAJP group (n=15), a BAJP+3-methyladenine (3-MA) group (n=15), and a BANA (bloodletting at nonacupoint; tail bleeding, n=15) group. Except for the control group, the AHH rat model was established in the other groups, and the corresponding treatment methods were adopted. Enzyme-linked immunosorbent assay (ELISA) was used to detect creatine kinase isoenzyme MB (CK-MB) and cardiac troponins I (CTnI) levels in serum and superoxide dismutase (SOD) and malondialdehyde (MDA) levels in myocardial tissue. Hematoxylin-eosin (HE) staining was used to observe myocardial injury, and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) staining was used to observe cell apoptosis. Transmission electron microscopy detection was used to observe mitochondrial damage and autophagosomes in the myocardium. The mitochondrial membrane potential of the myocardium was analyzed with the fluorescent dye JC-1. Mitochondrial respiratory chain complex (complex I, III, and IV) activities and ATPase in the myocardium were detected by mitochondrial respiratory chain complex assay kits. Western blot analysis was used to detect the autophagy index and hypoxia inducible factor-1α (HIF-1α)/Bcl-2 and adenovirus E1B 19k Da-interacting protein 3 (BNIP3) signaling. RESULTS: BAJP reduced myocardial injury and inhibited myocardial cell apoptosis in AHH rats. BAJP pretreatment decreased MDA levels and increased SOD levels in AHH rats (all P<0.01). Moreover, BAJP pretreatment increased the mitochondrial membrane potential (P<0.01), mitochondrial respiratory chain complex (complexes I, III, and IV) activities (P<0.01), and mitochondrial ATPase activity in AHH rats (P<0.05). The results from electron microscopy demonstrated that BAJP pretreatment improved mitochondrial swelling and increased the autophagosome number in the myocardium of AHH rats. In addition, BAJP pretreatment activated the HIF-1α/BNIP3 pathway and autophagy. Finally, the results of using 3-MA to inhibit autophagy in BAJP-treated AHH rats showed that suppression of autophagy attenuated the treatment effects of BAJP in AHH rats, further proving that autophagy constitutes a potential target for BAJP treatment of AHH. CONCLUSION BAJP is an effective treatment for AHH-induced myocardial injury, and the mechanism might involve increasing HIF-1α/BNIP3 signaling-mediated autophagy and decreasing oxidative stress.
Animals ; Rats ; Acupuncture Therapy ; Altitude ; Apoptosis ; Autophagy ; Bloodletting ; Hypoxia/metabolism* ; Membrane Proteins/pharmacology* ; Mitochondrial Proteins/pharmacology* ; Oxidative Stress ; Rats, Sprague-Dawley

OBJECTIVE: According to the characteristics of spinal burst fractures in high-altitude areas and the local medical conditions, to explore the clinical efficacy of short-segment fixation with pedicle screws combined with screw placement in injured vertebrae in the treatment of thoracolumbar burst fractures. METHODS: From August 2018 to December 2021, 12 patients with single-vertebral thoracolumbar burst fractures without neurological symptoms were treated with injured vertebral screw placement technique, including 7 males and 5 females;aged 29 to 54 years old, with an average of(42.50±7.95) years old;6 cases of traffic accident injury, 4 cases of high fall injury, 2 cases of heavy object injury;2 cases of T₁₁, 4 cases of T₁₂, 3 cases of L₁, 2 cases of L₂, and 1 case of L₃. In the operation, screws were first placed in the upper and lower vertebrae of the fracture, pedicle screws were placed in the injured vertebra, and connecting rods were installed, and the fractured vertebral body was reset by positioning and distraction. Visual analogue scale (VAS) and Japanese Orthopedic Association (JOA) scoring were used to evaluate the changes in pain and quality of life of patients, and the kyphotic correction rate and correction loss rate of the injured segment were measured by X-ray. RESULTS: All operations were successful without significant intraoperative complications. All 12 patients were followed up, the duration ranged from 9 to 27 months, with an mean of (17.75±5.79) months. VAS at 3 days after operation was significantly higher than that at admission (t=6.701, P=0.000). There was significant difference in JOA score between 9 months after operation and at admission (t=5.085, P=0.000). Three days after operation, Cobb angle was (4.42±1.16)°, and the correction rate was (82±5)% compared with (25.67±5.71)° at admission. Cobb angle was (5.08±1.24) °at 9 months after operation, with a corrected loss rate of (16±13)%. No loosening or breakage of internal fixation was found. CONCLUSION Under the high-altitude hypobaric and hypoxic environment, the effect of the operation should be ensured while reducing the trauma. The application of the technique of placing screws on the injured vertebra can effectively restore and maintain the height of the injured vertebra, with less bleeding and shorter fixed segments, which is an effective method.
Male ; Female ; Humans ; Adult ; Middle Aged ; Pedicle Screws ; Altitude ; Quality of Life ; Lumbar Vertebrae/injuries* ; Thoracic Vertebrae/injuries* ; Spinal Fractures/surgery* ; Fracture Fixation, Internal/methods* ; Fractures, Compression ; Treatment Outcome ; Fractures, Comminuted