1.Nanopackaged Astaxanthin Improves Demyelination in Multiple Sclerosis Model Mice by Scavenging Excessive Endogenous Formaldehyde
Wan-Jia LÜ ; Xin ZENG ; Zhi-Qian TONG ; Yang XING ; Xu YANG ; Mei-Na WU ; Ping MA
Progress in Biochemistry and Biophysics 2026;53(2):442-457
ObjectiveMultiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS); however, its underlying neurological pathogenic mechanisms remain incompletely understood. Endogenous formaldehyde (FA), a metabolic byproduct of methylation-demethylation cycles, has recently been implicated in neurotoxicity, oxidative damage, and cognitive impairment. This study aimed to investigate whether excessive FA contributes to myelin sheath demyelination in mice and to evaluate the protective effects and mechanisms of two FA-elimination strategies: sodium bisulfite (NaHSO3), a classical FA scavenger, and polyethylene glycol-modified astaxanthin nanoparticles (PEG-ATX@NPs), a brain-targeted nano-antioxidant formulation. MethodsA chronic demyelination model was established by feeding female C57BL/6J mice a diet containing 0.2% cuprizone (CPZ) for four weeks, followed by a two-week intervention period. Eighty mice were randomly assigned to four groups: NS (normal saline), CPZ+NS, CPZ+NaHSO3, and CPZ+PEG-ATX@NPs. Behavioral tests, including open-field, Y-maze, and pole-climbing assays, were conducted to assess locomotor activity, motor coordination, and working memory. FA levels in serum, corpus callosum, and spinal cord were measured using an Na-FA fluorescent probe and quantified via in vivo and ex vivo fluorescence imaging. Neuroinflammatory responses were evaluated by measuring TNF-α, IL-1β, and IL-6 levels using ELISA, while oxidative stress was assessed by reactive oxygen species (ROS) fluorescence intensity. Demyelination was examined via Luxol fast blue staining, and microglial activation was analyzed by Iba1 immunofluorescence. Correlation analyses were performed to explore relationships among FA levels, inflammatory cytokines, ROS intensity, and behavioral parameters. ResultsCompared with the NS group, mice in the CPZ+NS group exhibited significant weight loss, impaired motor coordination and memory, and markedly reduced myelin regeneration (P<0.05). FA levels and pro-inflammatory cytokines were significantly elevated in serum, corpus callosum, and spinal cord (P<0.05). FA-associated fluorescence in brain and spinal tissues, as well as ROS intensity across all tissues examined, also increased substantially (P<0.05). CPZ treatment induced pronounced microglial activation and severe demyelination in the corpus callosum (P<0.01). Both NaHSO3 and PEG-ATX@NPs effectively reduced FA accumulation in the brain and spinal cord, attenuated demyelination, suppressed microglial activation, decreased inflammatory cytokine levels, and improved motor and cognitive performance. These results confirm that CPZ induced severe demyelination accompanied by oxidative stress, neuroinflammation, and abnormal FA accumulation. Following intervention with either NaHSO3 or PEG-ATX@NPs, endogenous FA levels in the CNS were substantially reduced. Both treatments alleviated demyelination and significantly decreased the number of activated microglia. Levels of TNF-α, IL-1β, and IL-6 in serum, corpus callosum, and spinal cord were downregulated. Behavioral performance improved significantly, as evidenced by enhanced locomotor activity, better coordination, and improved memory function. These findings indicate that both FA-scavenging agents mitigate CPZ-induced biochemical and behavioral abnormalities. ConclusionThis study demonstrates that excessive endogenous FA is closely associated with cognitive impairment, inflammatory dysregulation, and demyelination in a CPZ-induced chronic demyelination mouse model. Clearing abnormally elevated FA effectively reduces neuroinflammation, suppresses microglial overactivation, decreases oxidative stress, and alleviates demyelination, ultimately improving motor and cognitive outcomes in mice. These results suggest that targeting endogenous FA represents a promising therapeutic strategy for MS and other demyelinating disorders. Further investigations are warranted to explore the long-term safety, dosage optimization, and molecular pathways involved in FA-mediated neurotoxicity.
2.Nanopackaged Astaxanthin Improves Demyelination in Multiple Sclerosis Model Mice by Scavenging Excessive Endogenous Formaldehyde
Wan-Jia LÜ ; Xin ZENG ; Zhi-Qian TONG ; Yang XING ; Xu YANG ; Mei-Na WU ; Ping MA
Progress in Biochemistry and Biophysics 2026;53(2):442-457
ObjectiveMultiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS); however, its underlying neurological pathogenic mechanisms remain incompletely understood. Endogenous formaldehyde (FA), a metabolic byproduct of methylation-demethylation cycles, has recently been implicated in neurotoxicity, oxidative damage, and cognitive impairment. This study aimed to investigate whether excessive FA contributes to myelin sheath demyelination in mice and to evaluate the protective effects and mechanisms of two FA-elimination strategies: sodium bisulfite (NaHSO3), a classical FA scavenger, and polyethylene glycol-modified astaxanthin nanoparticles (PEG-ATX@NPs), a brain-targeted nano-antioxidant formulation. MethodsA chronic demyelination model was established by feeding female C57BL/6J mice a diet containing 0.2% cuprizone (CPZ) for four weeks, followed by a two-week intervention period. Eighty mice were randomly assigned to four groups: NS (normal saline), CPZ+NS, CPZ+NaHSO3, and CPZ+PEG-ATX@NPs. Behavioral tests, including open-field, Y-maze, and pole-climbing assays, were conducted to assess locomotor activity, motor coordination, and working memory. FA levels in serum, corpus callosum, and spinal cord were measured using an Na-FA fluorescent probe and quantified via in vivo and ex vivo fluorescence imaging. Neuroinflammatory responses were evaluated by measuring TNF-α, IL-1β, and IL-6 levels using ELISA, while oxidative stress was assessed by reactive oxygen species (ROS) fluorescence intensity. Demyelination was examined via Luxol fast blue staining, and microglial activation was analyzed by Iba1 immunofluorescence. Correlation analyses were performed to explore relationships among FA levels, inflammatory cytokines, ROS intensity, and behavioral parameters. ResultsCompared with the NS group, mice in the CPZ+NS group exhibited significant weight loss, impaired motor coordination and memory, and markedly reduced myelin regeneration (P<0.05). FA levels and pro-inflammatory cytokines were significantly elevated in serum, corpus callosum, and spinal cord (P<0.05). FA-associated fluorescence in brain and spinal tissues, as well as ROS intensity across all tissues examined, also increased substantially (P<0.05). CPZ treatment induced pronounced microglial activation and severe demyelination in the corpus callosum (P<0.01). Both NaHSO3 and PEG-ATX@NPs effectively reduced FA accumulation in the brain and spinal cord, attenuated demyelination, suppressed microglial activation, decreased inflammatory cytokine levels, and improved motor and cognitive performance. These results confirm that CPZ induced severe demyelination accompanied by oxidative stress, neuroinflammation, and abnormal FA accumulation. Following intervention with either NaHSO3 or PEG-ATX@NPs, endogenous FA levels in the CNS were substantially reduced. Both treatments alleviated demyelination and significantly decreased the number of activated microglia. Levels of TNF-α, IL-1β, and IL-6 in serum, corpus callosum, and spinal cord were downregulated. Behavioral performance improved significantly, as evidenced by enhanced locomotor activity, better coordination, and improved memory function. These findings indicate that both FA-scavenging agents mitigate CPZ-induced biochemical and behavioral abnormalities. ConclusionThis study demonstrates that excessive endogenous FA is closely associated with cognitive impairment, inflammatory dysregulation, and demyelination in a CPZ-induced chronic demyelination mouse model. Clearing abnormally elevated FA effectively reduces neuroinflammation, suppresses microglial overactivation, decreases oxidative stress, and alleviates demyelination, ultimately improving motor and cognitive outcomes in mice. These results suggest that targeting endogenous FA represents a promising therapeutic strategy for MS and other demyelinating disorders. Further investigations are warranted to explore the long-term safety, dosage optimization, and molecular pathways involved in FA-mediated neurotoxicity.
3.Chloroplast genome structure of Artemisia vestita and its significance for species identification
Jin-ren LI ; Na-jia SUOLANG ; Zhi-li ZHAO ; Dol-kar MIGMAR ; ALA Kelsang GYAB ; Liang-hong NI
Chinese Traditional Patent Medicine 2025;47(6):1901-1909
AIM To sequence the chloroplast genome of Artemisia vestita Wall.ex Bess.METHODS Based on ethnobotanical surveys,sample collection and original plant identification were carried out.The chloroplast genome was sequenced using the Illumina platform,followed by assembly and annotation.A comprehensive comparative analysis was conducted with six Artemisia species.The maximum likelihood(ML)phylogenetic tree was constructed based on the chloroplast genome sequences of A.vestita and 32 other Asteraceae species,with Leptocodon hirsutus D.Y.Hong of Campanulaceae as outgroup.RESULTS The chloroplast genome of A.vestita was 151 204 bp in length,including a small single-copy region of 18 331 bp,a large single-copy region of 82 949 bp,and inverted repeat regions of 24 962 bp,with a total GC content of 37.45%.134 genes were annotated,including 89 protein-coding genes,8 ribosomal RNA genes,and 37 transfer RNA genes.A total of 67 SSRs and 44 LSRs were detected in the chloroplast genome.Comparative analysis with closely related species of Artemisia revealed 3 highly variable genes(clpP,rpl36,ycf1)and 6 highly variable intergenic regions(trnK-UUU-matK,rps18-rpl20,rpl36-infA,rpl14-rpl16,rpl16-rpl3 and trnL-UAG-ccsA),which could serve as candidate DNA barcodes for Artemisia identification.Phylogenetic analysis showed that Artemisia formed a highly supportive monophyletic group,with A.vestita and A.gmelinii Web.ex Stechm.being closely related.CONCLUSION This study may provide fundamental data for phylogenetic analysis of Artemisia,taxonomic identification and DNA barcoding construction of Tibetan herb.
4.Characteristics and factors affecting treatment in hospitalized patients with abnormal uterine bleeding in sub-plateau region
Dan-feng DU ; Ru-juan WANG ; Rong-qun CHA ; Ping JIANG ; Li-qin WANG ; Xi CHEN ; Li-na YANG ; Zhi-yong WU
Fudan University Journal of Medical Sciences 2025;52(3):408-415,423
Objective To investigate the clinical characteristics of women with abnormal uterine bleeding(AUB)in sub-plateau regions and analyze the factors affecting their treatment methods.Methods AUB patients who were hospitalized from Jan 1,2018 to Dec 31,2022,in a sub-plateau region(Yongping County People's Hospital of Yunnan Province)with an average altitude of 1 620 meters were selected.The general clinical characteristics of the patients were summarized,and patients were classified into two categories(with or without uterine structural lesion)and nine subtypes(PALM-COEIN)according to the FIGO recommended etiological classification guidelines.Then the patients were divided into groups based on the presence or absence of uterine structural lesions,ethnic group(Han and minority),conservative drug treatment and surgical treatment groups,blood transfusion and non-blood transfusion groups.Binary Logistic regression analysis was used to identify factors affecting treatment methods.Results A total of 481 AUB patients enrolled,and the delayed consultation rate was as high as 80.46%,and the proportion of overweight and obese patients was 49.90%,which was higher than the average level among Chinese women.The main cause was AUB-O(AUB-ovulatory dysfunction),accounting for 78.59%of cases,the proportion of patients with delayed medical treatment was higher than those without delayed medical treatment(82.17%vs.74.47%).Patients who received blood transfusion were significantly younger,had lower hemoglobin(HGB)levels,fewer pregnancies,and lower BMI compared to those in the non-blood transfusion group(P<0.05).Univariate analysis showed that the surgical treatment group had older age,longer onset time,higher HGB levels,more pregnancies and deliveries,higher BMI,a higher proportion of Han ethnicity patients,lower rates of non-blood transfusion,higher rates of hypertension,and more uterine structural lesions compared to the conservative drug treatment group.Multivariate regression analysis revealed that blood transfusion treatment reduced the probability of surgical treatment.Age and uterine structural lesions were risk factors for requiring surgical treatment,for each additional year of age,the risk of undergoing surgical treatment increased by 10%.The risk of requiring surgical treatment for patients with uterine structural lesions was 2.987 times higher than for those without.Conclusion AUB patients in this sub-plateau regions have a high rate of delayed consultation and a high proportion of overweight and obesity,with AUB-O being the primary cause.Older age and the presence of uterine structural lesions were risk factors for requiring surgical treatment.
5.Establishment and application of ultra-fast real-time PCR for Brucella detection
Zhen-na XU ; Zhi-peng WU ; Wei-bin HONG ; Zhi-shen GUAN ; Qi-ming LIN ; Zuan-lan MO ; Yi-fei YE ; Hai-yan XIE ; Min LI ; Yan-qiu ZHU ; Xiao-jun LI ; Xian-peng ZHANG
Chinese Journal of Zoonoses 2025;41(3):278-283
This study was aimed at establishing a method of ultra-fast quantitative PCR for Brucella detection.We used an exogenous recombinant plasmid as the internal reference and targeted the T4SS secretion system,an important Brucella viru-lence factor,to design specific primers and probes.The sensitivity,specificity,and repeatability of this method were evaluated,and a standard curve was constructed.The coincidence rate of detection findings with this method versus quantitative PCR was determined.This method markedly decreased the detection time to only 10 minutes.The standard curve demonstrated a good linear relationship(Y=-3.410 7x+38.357,R2=0.998 5)with a low minimum detection limit of 10 copies/μL.The method exhibited good specificity and did not specifically amplify several common clinical bacteria other than Brucella.The de-tection of three concentrations of positive plasmids yielded coefficients of variation(CVs)of 0.20%to 0.91%,thus demonstra-ting the method's excellent repeatability.Furthermore,140 clinical samples were analyzed concurrently with the fluorescence PCR method,which yielded a 100%compliance rate and consistent results.Our findings indicated that the Brucella ultra-fast quantitative PCR was ultrafast;had high sensitivity,high specificity,and good specificity;and can be used for the clinical de-tection of Brucella and emergency investigation of epidemics.Therefore,this method is valuable for the early diagnosis of Bru-cella.
6.ALKBH5 mediated m6A modification of NLRP3 promotes cardiomyocytes pyroptosis in mice with myocardial infarction
Miao-miao ZHAI ; Jian-jian YIN ; Zhi-mo WANG ; Yue-jiao ZHOU ; Qing-wen YU ; Pei WANG ; Li-rong ZHANG ; Sheng-na HAN
Chinese Pharmacological Bulletin 2025;41(3):434-444
Aim To investigate the effects of m6A demethylase ALKBH5 on cardiomyocytes pyroptosis in mice with myocardial infarction(MI).Methods The MI model of left anterior descending coronary artery ligation surgery was established by knocking down ALKBH5 using adeno-associated virus,and the hypox-ia model of mouse cardiomyocytes(HL-1)was estab-lished by knocking down small interfering RNA.The effects of ALKBH5 on the pyroptosis of MI mice and hypoxic HL-1 cells were observed.Subsequently,mechanism studies were conducted at the cellular lev-el,and the binding of ALKBH5 and IGF2BP2 to NL-RP3 mRNA was detected through RNA pull down and RNA immunoprecipitation(RIP)experiments.The MeRIP-qPCR method was used to determine the effects of ALKBH5 on the mRNA m6A level of NLRP3.Acti-nomycin D for RNA stability experiments were conduc-ted to detect the effects of ALKBH5 and IGF2BP2 on the stability of NLRP3 mRNA.Results Knocking down ALKBH5 in vivo and in vitro both inhibited NL-RP3 inflammasome activation and alleviated pyroptosis in MI mice and hypoxic HL-1 cells.Mechanistically,the results showed that NLRP3 mRNA could bind to ALKBH5 protein in HL-1 cells;knocking down ALK-BH5 could increase the m6A level of NLRP3 and re-duce the stability of NLRP3 mRNA;subsequently,it was confirmed that NLRP3 mRNA and IGF2BP2 pro-tein bound to each other;knocking down IGF2BP2 in-creased the mRNA stability of NLRP3.The Rescue ex-periment showed that knocking down IGF2BP2 re-versed the decrease in NLRP3 mRNA expression caused by knocking down ALKBH5.Conclusions ALKBH5 mediated m6A modification of NLRP3 pro-motes cardiomyocytes pyroptosis in mice with myocardi-al infarction.
7.Efficacy and safety of a facilitated percutaneous coronary intervention with half-dose recombinant staphylokinase in ST-segment elevation myocardial infarction
Tian-yu WU ; Wen-hao ZHANG ; Peng-sheng CHEN ; Chen LI ; Tian WU ; Zhan LÜ ; Tong WANG ; Kun LIU ; Zhi-wen TAO ; Xiao-xuan GONG ; Liang YUAN ; Yong LI ; Bo CHEN ; Xin CHEN ; Zeng-guang CHEN ; Nai-quan YANG ; Yuan-yuan SANG ; Xiao-yan WANG ; Bai-hong LI ; Li ZHU ; Guo-yu WANG ; Xin ZHAO ; Chuan LU ; Jun JIANG ; Rui-na HAO ; Chun-jian LI
Chinese Journal of Interventional Cardiology 2025;33(8):431-438
Objective To investigate the clinical efficacy and safety of facilitated percutaneous coronary intervention(PCI)with half-dose recombinant staphylokinase(r-SAK)in patients with ST-segment elevation myocardial infarction(STEMI)who are expected to undergo PCI within 120 minutes.Methods From October 2021 to August 2022,a total of 200 STEMI patients in eight centers were included and randomly assigned in a 1﹕1 ratio to either r-SAK group or control group.Patients received loading doses of aspirin and ticagrelor and intravenous heparin and were randomized to receive an intravenous bolus of either 5 mg r-SAK or normal saline prior to PCI.The outcomes were set as ST-segment resolution(STR)at 60-90 minutes after PCI,the proportion and transition of pathological Q waves on the 5th day after PCI,and the proportion of high-sensitivity cardiac troponin T(hs-cTnT)peaking within 12 hours of onset.The safety outcome was major bleeding events defined as Bleeding Academic Research Consortium(BARC)≥type 3 bleeding during hospitalization.Results Compared with the control group,the r-SAK group had a higher proportion of STR≥70%within 60-90 minutes after PCI(58.3%vs.40.3%,P=0.009);a lower proportion of pathological Q waves(59.1%vs.74.1%,P=0.040);a lower rate of Q wave progression(14.8%vs.43.2%,P<0.001);a higher rate of Q wave disappearance(12.5%vs.3.7%,P=0.027);and a higher proportion of hs-cTnT peaking within 12 hours of symptom onset[31/40(77.5%)vs.17/33(51.5%),P=0.027].Regarding the safety outcome,no significant difference in BARC≥type 3 bleeding was found between the two groups during hospitalization(P>0.05).Conclusions For STEMI patients who were expected to undergo primary PCI within 120 minutes of symptom onset,the facilitated PCI with half-dose r-SAK significantly increased the proportion of STR≥70%at 60-90 minutes after PCI,reduced the formation of pathological Q waves,and shortened the time to peak hs-cTnT,without increasing the risk of bleeding,which should be an alternative reperfusion strategy worthy of further study.
8.Cordyceps sinensis ameliorates renal interstitial fibrosis in mice by IL-6 trans-signaling pathway
Ying-xue SUN ; Jun CHEN ; Pei-chen TANG ; Jian ZHANG ; Wei-ze CHEN ; Zhi-xin YAN ; Na-na SONG
Fudan University Journal of Medical Sciences 2025;52(1):1-15
Objective To investigate the effect of cordyceps sinensis(CS)on the activation of fibroblasts through IL-6 trans-signaling pathway and its specific mechanism in the treatment of renal fibrosis.Methods Renal fibrosis mouse model was established by unilateral ischemia/reperfusion(UIR),and the mice were administered intragastrically CS,soluble glycoprotein 130 Fc(sgp130Fc)or Hyper-IL-6.Masson's trichrome staining was utilized to identify tubulointerstitial fibrosis.PAS staining was utilized to assess the extent of renal injury.Western blot was employed to analyze the expression levels of fibrosis markers[alpha-smooth muscle actin(α-SMA),fibronectin(FN)]and proteins associated with IL-6 trans-signaling pathway[phosphorylated signal transducer and activator of transcription 3(p-STAT3),soluble interleukin-6 receptor(sIL-6R)].The expression and localization of proteins were additionally detected by immunohistochemistry,immunofluorescence and qPCR.The effect of cordyceps sinensis extract cordycepin on IL-6 trans-signaling in fibroblasts was further investigated in vitro.Results The results from in vivo experiments showed that administration of CS during the chronic phase demonstrated a beneficial protective impact on inflammation and fibrosis in the affected kidney,and serum creatinine levels and collagen deposition were decreased.Western blot analysis revealed a decrease in the expression levels of α-SMA,FN,as well as IL-6 trans-signaling pathway protein p-STAT3,sIL-6R in the treatment group.Additionally,the mRNA expression levels of chemokines monocyte chemoattractant protein-1(MCP-1)and C-X-C motif chemokine ligand 12(CXCL12)were also decreased in the CS treatment group.Additionally,Hyper-IL-6 can partially counteract the therapeutic effects of CS.In vitro experiments further demonstrated that cordycepin inhibited the secretion of IL-6 from NRK-52E.Combined treatment of recombinant IL-6 and sIL-6R protein activated NRK-49F,leading to a significant increase in α-SMA,FN,and p-STAT3 expression levels.Cordycepin or sgp130Fc treatment significantly inhibited the proliferation of fibroblasts induced by IL-6 trans-signaling pathway.Conclusion CS can significantly reduce IL-6 secretion by renal tubular epithelial cells and inhibit the activation of IL-6 trans-signaling pathway in fibroblasts,thereby ameliorating renal interstitial fibrosis.
9.The mechanism of GPR120 gene inhibiting NLRP3 inflammasome activation in protection of septic lung injury
Kai ZHANG ; Yi-qin HUANG ; Zi-yan ZHANG ; Lin MI ; Na YU ; Zhi-jun BAO
Fudan University Journal of Medical Sciences 2025;52(1):44-54
Objective To investigate the role of the GPR120 gene in the progression of sepsis,explore the molecular mechanisms through which GPR120 gene regulates NOD-,LRR-and pyrin domain-containing protein 3(NLRP3)inflammasome activation and macrophage polarization.Methods The blood and pleural fluid samples were collected from the sepsis patients and the control group.The expression of inflammatory factors and the associated proteins were detected by flow cytometry and ELISA.C57BL/6 mice and monocyte-macrophage cell line(Raw264.7)were treated with lipopolysaccharide(LPS)to construct the sepsis models.After the intervention of GPR120 agonist TUG891,the expression of GPR120 gene,NLRP3 inflammasome protein and macrophage polarization protein were detected between the control group and the sepsis group.Results The expression of inflammatory factors,such as IL-1β in the serum of septic patients,significantly increased compared with the control(P<0.001).And the expression of inflammasome proteins such as NLRP3,Caspase-1 and IL-1β in the pleural fluid also increased(all P<0.05).In vivo,LPS could induce severe inflammation in lung tissue,the GPR120 gene expression decreased in lung tissue,and inflammatory factors were up-regulated in mouse serum(P<0.01).The inflammasome-associated protein and M1 type polarization of macrophages were enhanced,the TUG891 could reduce the inflammatory response,inhibit the NLRP3 inflammasome activating,and promote the M2 polarization of macrophages(P<0.01).In vitro,LPS could inhibit the intracellular GPR120 expression.The inflammatory factors secreted more in LPS-induced sepsis cells.TUG891 could promote the up-regulation of GPR120 protein and alleviate the secretion of inflammatory factors(P<0.05).Conclusion In sepsis,GPR120 gene activation could inhibit the NLRP3 inflammasome activation,promote macrophage polarization,and reduce the inflammatory damage,thereby delay the rapid progression of sepsis.
10.Development and application of pilot hypoxia endurance testing system
Lin-xia LI ; Guo-yun MAO ; Ming-rui HU ; Jia-ling XU ; Yao-xuan JI ; Na ZHI ; Yan-qing BAI ; Yun-ying WANG
Chinese Medical Equipment Journal 2025;46(10):23-28
Objective To develop a hypoxia endurance testing system for aviation physiological training of pilots.Methods The hypoxia endurance testing system comprised a low-oxygen mixed gas generator,a pressurization system for low-oxygen mixed gas and a personal breathing apparatus.The low-oxygen mixed gas generator consisted of a main unit composed of an air compressor,a filter,a buffer tank,polymer membrane,a control module,sensors and regulators,wire cables,supporting hoses,etc.;the pressurization system for low-oxygen mixed gas was made up of a protective box,a cooling fan,a motor and a driver,a control module,a solenoid valve,a convergence block,a pressure gauge,etc.;the personal breating apparatus was composed of a gas cylinder,a pressure reducer,an oxygen supply regulator,etc.Forty-eight subjects were selected for hypoxia exposure tests to verify the effectiveness of the system.Results The system developed had the functions of low-oxygen gas preparation,pressurized filling and hypoxia experiment,and the experimental results indicated the acute hypoxia exposure by the system significantly caused signs and symptoms of hypoxia and weakened physiological functions.Conclusion The system developed gains advantages in high accuracy of gas volume fraction control,safety and remarkable effect of simulated hypoxia,and can be an effective tool for acute high-altitude hypoxia testing and training of pilots.[Chinese Medical Equipment Journal,2025,46(10):23-28]

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