1.Factors affecting and identification of key environmental determinants of the Oncomelania hupensis snail density in the Yangtze River Delta based on machine learning models
Yinlong LI ; Qin LI ; Suying GUO ; Shizhen LI ; Lijuan ZHANG ; Chunli CAO ; Jing XU
Chinese Journal of Schistosomiasis Control 2026;38(1):14-19
Objective To identify factors affecting and key environmental factors of the Oncomelania hupensis snail density in the Yangtze River Delta region using machine learning methods. Methods Administrative village-level O. hupensis snail survey data in the Yangtze River Delta (including Shanghai Municipality, Jiangsu Province, Zhejiang Province and Anhui Province) from 2011 to 2021 were retrieved from the Information Management System for Parasitic Disease Control of Chinese Center for Disease Control and Prevention. Environmental factor data were captured from the Google Earth Engine platform, including elevation, slope, terrain, normalized difference vegetation index (NDVI), vegetation type, soil type, total petroleum hydrocarbon (TPH), ammonium nitrogen, inorganic nitrogen, dissolved oxygen, pH of water, chemical oxygen demand (COD) and inorganic phosphorus, and climatic factor data in the study region were retrieved from the Copernicus Climate Data Store, including annual precipitation, aridity index and annual mean temperature (AMT). O. hupensis snail survey data in the Yangtze River Delta region from 2011 to 2021 were randomly divided into a training set (70%) and a test set (30%), and five machine learning models were selected for machine learning model construction and comparative analysis of the O. hupensis snail density using the software R 4.3.0, including random forest (RF), eXtreme gradient boosting (XGBoost), support vector machine (SVM), gradient boosting machine (GBM) and neural network (NN). The XGBoost model was employed to construct a predictive model for the O. hupensis snail density, and the impact of each environmental factor on O. hupensis snail distribution was quantified. The SHapley Additive exPlanations (SHAPs) values were calculated to estimate the average contribution of each variable to the model prediction, and the core environmental factors affecting the O. hupensis snail population density were screened. Results Among the five machine learning models, the XGBoost model exhibited the optimal comprehensive performance, with the coefficient of determination (R2) of 0.855, mean squared error (MSE) of 0.188, root mean squared error (RMSE) of 0.434 and mean absolute error (MAE) of 0.155, respectively. Analysis of factors affecting the O. hupensis snail density with the XGBoost model showed that among the 16 environmental factors, the top four high-impact factors ranked by SHAPs values included annual precipitation, elevation, aridity index and NDVI, with cumulative SHAPs contributions of 75%, which was higher than that of other environmental factors. If NDVI was higher than 0.6, the O. hupensis snail density increased with NDVI and peaked if NDVI was 0.8 (1.60 snails/0.1 m2). The O. hupensis snail density increased with elevation if the elevation ranged from 14 to 40 m, and slowly rose if the annual precipitation ranged from 900 to 1 300 mm, and then increased rapidly to the peak (1.52 snails/0.1 m2) if the annual precipitation ranged from 1 300 to 1 500 mm. In addition, the O. hupensis snail density increased rapidly to the maximum (1.60 snails/0.1 m2) if the aridity index ranged from 0.8 to 1.1, and decreased gradually if the aridity index exceeded 1.1. Conclusions The XGBoost model shows excellent performance in prediction of the O. hupensis snail density and identification of key environmental factors in the Yangtze River Delta region. Annual precipitation, elevation, aridity index and NDVI are key environmental factors affecting the distribution and density of O. hupensis snails in the Yangtze River Delta region.
2.Transcriptomic responses of Bulinus globosus to extreme temperature and drought stress
Xinyao WANG ; Dandan PENG ; Ying YANG ; Jianfeng ZHANG ; Zhiqiang QIN ; Kun YANG ; Shizhu LI ; Jing XU
Chinese Journal of Schistosomiasis Control 2026;38(1):29-37
Objective To examine the impact of extreme temperature and drought stress on the survival of Bulinus globosus, so as to provide the theoretical evidence for the genomic research of Bulinus in absence of reference genes. Methods B. globosus snail samples were collected from Kiwani Shehia in Pemba Island, Zanzibar, Tanzania, and offspring snails were obtained through laboratory breeding and reproduction. A total of 120 10-week-old B. globosus snails from the same generation were selected and randomly assigned into four groups, including the high-temperature drought (HD) group, normal temperature drought (D) group, low-temperature drought (LD) group, and the control (C) group, of 30 snails in each group. Snails in HD, D, and LD groups were placed in beakers containing dry soil at the bottom and subsequently housed in climate chambers at 35, 26 ℃, and 10 ℃, respectively, while snails in Group C were maintained in 500 mL petri dishes containing dechlorinated tap water at 26 ℃. Following 3 days of breeding, living snails in each group were collected, and soft tissues were dissected and isolated. Total RNA was extracted from snail soft tissues for library construction, followed by high-throughput sequencing on the Illumina HiSeq 4000 sequencing system. De novo transcriptome assembly was performed using the Trinity software, and the longest transcripts were selected as unigenes. Gene functional annotations of unigenes were conducted using the Diamond software against Gene Ontology (GO) knowledgebase, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database, NCBI non-redundant (NR) protein sequences database, Protein Family (Pfam) database, and UniProtKB/Swiss-Prot (Swiss-Prot) knowledgebase. GO and KEGG enrichment analyses of differentially expressed genes (DEGs) were performed using the topGO and clusterProfiler software, respectively. In addition, four relevant genes were selected for validation using a real-time quantitative PCR (qRT-PCR) assay to verify the reliability of transcriptome sequencing results. Results Following 3 days of breeding, there were 7, 20, 28, and 30 survival B. globosus snails in HD, LD, D, and C groups, with corresponding survival rates of 23.33% (7/30), 66.67% (20/30), 93.33% (28/30), and 100.00% (30/30), respectively (χ2 = 52.72, P < 0.001). De novo transcriptome assembly generated 176 942 unigenes, with annotation rates of 0.98%, 13.49%, 26.46%, 12.48%, and 14.39% against GO knowledgebase, KEGG pathway database, NR protein sequences database, Pfam database, and Swiss-Prot knowledgebase, respectively. There were 33 up-regulated and 72 down-regulated genes in Group D, 483 up-regulated and 815 down-regulated genes in Group HD, and 245 up-regulated and 172 down-regulated genes in Group LD relative to in Group C. Following removal of overlapping genes across groups and unmatched genes, 11 candidate genes were identified. GO and KEGG analyses revealed 3 heat shock protein (HSP)-related DEGs in these 11 candidate genes, which were annotated as HSP12.2, HSP70, and HSP20 genes and were all significantly up-regulated in each treatment group. Three immune and nervous system-related DEGs were identified, and were all significantly down-regulated in each treatment group, which were involved in the neural cell adhesion molecule L1-like protein pathway, fibrinogen binding protein pathway, and leukocyte elastase inhibitor-like protein pathway. qRT-PCR assay quantified that the expression trends of four genes related to temperature and drought stress across different treatment groups were highly consistent with transcriptome sequencing data. Conclusion The survival rate of B. globosus significantly reduces under combined stresses of extreme temperature and drought, possibly due to an imbalance in its cellular homeostasis regulatory system.
3.Diagnostic value of serum Mac-2 binding protein for the severity of schistosomiasis-induced liver fibrosis
Jun WU ; Meiqun LUO ; Shuying XIE ; Ronghua ZHU ; Hui XU ; Long TANG ; Fei HU ; Sheng DING
Chinese Journal of Schistosomiasis Control 2026;38(1):38-43
Objective To evaluate the value of serum Mac-2 binding protein (M2BP) for assessment of the severity of schisto somiasis-induced liver fibrosis, so as to provide insights into non-invasive diagnosis and disease surveillance of liver fibrosis caused by schistosomiasis. Methods A total of 234 individuals with a history of Schistosoma japonicum infection were sampled from Xinhua Village, Lushan City, Jiangxi Province from 2019 to 2020, and 234 serum samples were collected from all participants. All participants received B-ultrasound examinations of the liver. Serum samples were categorized into four groups (grades 0, Ⅰ, Ⅱ and Ⅲ schistosomiasis-induced liver fibrosis groups) according to B-ultrasound examination results, and then, each group was randomly divided into a receiver operating characteristic (ROC) curve group and an efficacy assessment group at a ratio of 7∶3. Serum M2BP concentration was measured in four groups using the enzyme-linked immunosorbent assay (ELISA), and differences in serum M2BP concentrations were compared with analysis of variance and Spearman correlation analysis. Serum M2BP concentration was subjected to ROC curve analysis among individuals with different grades of schistosomiasis-induced liver fibrosis in the ROC curve group to determine the optimal diagnostic threshold of M2BP concentration at different fibrosis grades, and the area under the ROC curve (AUC) was calculated to evaluate the diagnostic performance. The diagnostic accuracy was verified by comparing the accordance rate and Kappa consistency test in the efficacy assessment group. Results Among 234 serum samples, there were 79 samples with grade 0 schistosomiasis-induced liver fibrosis, 87 samples with Grade Ⅰ, 46 samples with Grade Ⅱ and 22 samples with Grade Ⅲ according to the B-ultrasound examinations. The mean serum M2BP concentrations were (0.40 ± 0.31) [95% confidence interval (CI): (0.33, 0.47)], (0.64 ± 0.48) [95% CI: (0.53, 0.74)], (1.76 ± 0.58) [95% CI: (1.59, 1.93)] μg/mL and (2.56 ± 0.93) [95% CI: (2.14, 2.97)] μg/mL in the four groups, respectively (F = 150.796, P < 0.001), and the severity of schistosomiasis-induced liver fibrosis significantly positively correlated with serum M2BP concentration (rs = 0.715, P < 0. 001). The sample sizes of grades 0, Ⅰ, Ⅱ and Ⅲ schistosomiasis-induced liver fibrosis sera were randomly allocated as follows: 55 versus 24, 61 versus 26, 32 versus 14, and 15 versus 7 in the ROC curve and efficacy assessment groups, respectively, and the serum M2BP concentrations were (0.39 ± 0.29) μg/mL and (0.42 ± 0.36) μg/mL (F = 0.196, P > 0.05), (0.59 ± 0.47) μg/mL and (0.75 ± 0.51) μg/mL (F = 1.967, P > 0.05), (1.73 ± 0.59) μg/mL and (1.85 ± 0.57) μg/mL (F = 0.417, P > 0.05), and (2.46 ± 0.64) μg/mL and (2.76 ± 1.41) μg/mL (F = 0.491, P > 0.05), respectively. ROC curve analysis showed that the optimal diagnostic thresholds of serum M2BP concentration were 0.347 86 μg/mL (AUC = 0.635, P < 0.05), 1.188 83 μg/mL (AUC = 0.938, P < 0.000 1) and 2.021 21 μg/mL (AUC = 0.821, P < 0.000 1) for grade Ⅰ, Ⅱ and Ⅲ schistosomiasis-induced liver fibrosis. In addition, the accordance rates between the optimal diagnostic threshold of serum M2BP and B-ultrasound examinations for predicting grade Ⅰ, Ⅱ and Ⅲ schistosomiasis-induceed liver fibrosis were 69.23%, 85.71% and 71.43% (χ2 = 1.340, P > 0.05), and the overall Kappa consistency test showed moderate consistency [Kappa = 0.608, 95% CI: (0.428, 0.788); Z = 6.609, P < 0.000 1]. Conclusions Serum M2BP may serve as a potential biomarker for assessing moderate to advanced schistosomiasis-induced liver fibrosis; however, its diagnostic value for early-stage schistosomiasis-induced liver fibrosis remains limited.
4.Construction of an index system for assessment of schistosomiasis transmission risk following natural disasters
Jingye SHANG ; Chenghang YU ; Zisong WU ; Xianhong MENG ; Huirong XU ; Chaofu WANG ; Bin ZHENG ; Shizhu LI ; Yang LIU
Chinese Journal of Schistosomiasis Control 2026;38(1):60-68
Objective To construct an index system for assessment of schistosomiasis transmission risk following natural disasters such as rainstorms, floods, earthquakes, mudslides, and landslides, so as to provide insights into rapid identification of schistosomiasis transmission risk post-disasters and formulation of targeted schistosomiasis control strategies. Methods An initial framework for the index system for assessment of schistosomiasis transmission risk following natural disasters was drafted through literature review, brainstorming, and focus group discussions. Two rounds of expert correspondence consultations were conducted using the Delphi method to refine and finalize the system, and the degrees of expert activeness, authority and endorse ment, and consensus were evaluated. In addition, the weights of each index were calculated using the analytic hierarchy process. Results A total of 18 experts participated in the consultation. The expert positive coefficients were 100.00% and 94.44% for two rounds of consultations, with authority coefficients of 0.92 and 0.94, respectively. The coefficients of coordination on the index importance, rationality and operability were 0.209, 0.185, 0.222 and 0.407, 0.214, 0.257 for two rounds of consultations, respectively, and all consistency tests were statistically significant (χ2 = 246.771 to 505.278, all P values < 0.001). Following two rounds of expert consultations, an index system consisting of 6 first-level indicators, 15 second-level indicators, and 49 third-level indicators was ultimately constructed. In terms of first-level indicators, “disaster situation”, “previous epidemics”, “healthcare guarantee”, “response capacity” and “emergency recovery” had the highest weights, each at 18.18%. Regarding second-level indicators, “Schistosoma japonicum infections in animals”, “S. japonicum infections in snails” and “medical treatment” had the highest weights, each at 7.35%. In terms of third-level indicators, ten items had the highest weights, including “identification of schistosomiasis cases”, “detection of S. japonicum infections in wild feces”, “detection of S. japonicum infections in snails”, “reserves of schistosomiasis diagnostic/testing reagents and consumables”, “reserves of chemotherapy agents for human and animal schistosomiasis”, “reserves of cercariacides”, “periodical surveillance on schistosomiasis”, “identification of schistosomiasis transmission risk and timely response”, “normal provision of diagnosis and treatment services” and “post-disaster schistosomiasis surveillance”, each at 2.40%. Conclusion A scientific, systematic, and practical index system has been constructed for assessment of schistosomiasis transmission risk following natural disasters, which may provide insights into rapid post-disaster identification of schistosomiasis transmission risk, formulation of targeted schistosomiasis control strategies and optimization of resource allocation.
5.Strengths, weaknesses, opportunities and threats analysis of diagnosis-related group in schistosomiasis control
Chinese Journal of Schistosomiasis Control 2026;38(1):74-78
As a novel healthcare management tool, diagnosis-related group (DRG) plays a significant role in standardization of medical behaviors, reduction of medical costs, and improvements of the utilization efficiency of medical resources. This article analyzes internal and external factors pertaining to the application of DRG in schistosomiasis control through a strengths, weaknesses, opportunities and threats (SWOT) analysis and discusses potential impacts, challenges, and development opportunities. DRG has shown significant potential in optimizing resources, standardizing diagnosis and treatment, and reducing expenses; however, it also suffers from problems of a great difficulty in grouping and a low informatization level at grassroots institutions. Optimization of diagnosis-related grouping and increased investments into grassroots institutions are therefore required to meet the special needs of schistosomiasis control, so as to improve the effectiveness of schistosomiasis control.
6.Advances in techniques for assessment of schistosomiasis transmission risk: a global perspective and China’s practice
Andong XU ; Hong ZHU ; Jing XU ; Shizhu LI
Chinese Journal of Schistosomiasis Control 2026;38(1):100-108
Based on review of global and Chinese schistosomiasis control progress and the evolution of control strategies, this article focuses on Chinese practical experiences of schistosomiasis control and systematically summarizes five key determinants for schistosomiasis transmission risk, including source of infections, intermediate host snails, high-risk populations, natural environments, and social factors. To address these risks and challenges associated with these determinants, the article reviews the advances in techniques for assessment of schistosomiasis transmission risk and their applications, including conventional risk assessment approaches, mathematical model-based tools for prediction of schistosomiasis transmission risk, and indicator-systembased techniques for assessment of schistosomiasis transmission risk. This review underscores the essential role of interdisciplinary integration and dynamic management in precision schistosomiasis control and recommends the intensification of verification of field adaptation and dynamic updates of indicator systems to promote the widespread application of assessment tools across diverse regions and contexts, so as to provide strategic guidance and methodological support to achieve the target for elimination of schistosomiasis across China in 2030.
7.Spinal cord stimulation for spinal cord injury from 1999 to 2025: a bibliometric analysis
Yuanyuan QI ; Haifeng GAO ; Lina LIU ; Yujie XIE ; Jing XU ; Feng GAO ; Liang CHEN ; Degang YANG ; Jun LI
Chinese Journal of Rehabilitation Theory and Practice 2026;32(4):373-386
ObjectiveTo analyze the research hotspots and development trends in the field of spinal cord stimulation (SCS) for spinal cord injury (SCI). MethodsLiterature about SCS for SCI was retrieve from the Web of Science (WOS) Core Collection database, with a time range from January, 1999 to July, 2025. VOSviewer 1.6.20 and CiteSpace 6.4.R2 were used to analyze the annual publication volume, countries, authors, institutions, journals and keywords. ResultsA total of 636 literatures were included. From 1999 to 2025, the overall publication trend in this field showed an upward trajectory, with recent years fluctuating but tending to stabilize. The country with the most publications was the United States (429 papers), followed by Russia (98 papers) and China (70 papers). The institution with the highest number of publications was the University of California, Los Angeles (76 papers), the author with the most publications was V. Reggie Edgerton (70 papers), and the journal with the most publications was Journal of Clinical Medicine (31 papers). The most frequently cited study focused on exploring the combination of epidural spinal cord stimulation with task-specific training to restore motor function in patients with complete SCI. Keyword analysis showed that the research hotspots in this field were mainly focused on neuroregulation mechanisms, recovery of motor and autonomic nervous dysfunction, artificial intelligence, closed-loop stimulation and brain-computer interface technology innovations. In recent years, the research focus gradually shifted from basic mechanisms to personalized and precise multifunctional rehabilitation strategies. ConclusionThe field of SCS for SCI has undergone phases of basic mechanism exploration and clinical application expansion. Current research hotspots and future trends focus primarily on the development of new stimulation paradigms and combined innovative technologies.
8.Effect of virtual reality biofeedback training combined with oral positioning therapy on dysphagia after oral cancer surgery
Mingxia XU ; Hui ZHU ; Piaopiao CHEN ; Kexin MENG ; Jie CHEN ; Jing CHEN ; Huifang SUN ; Yanyan SUN
Chinese Journal of Rehabilitation Theory and Practice 2026;32(4):445-452
ObjectiveTo explore the application of virtual reality biofeedback training combined with oral localization therapy in dysphagia after oral cancer surgery. MethodsFrom May, 2023 to July, 2024, 86 patients with dysphagia after oral cancer surgery in Zhejiang Provincial People's Hospital were randomly divided into control group (n = 43) and experimental group (n = 43). The control group received conventional swallowing function training, while the experimental group added virtual reality biofeedback training combined with oral positioning therapy, for four weeks. The Standardized Swallowing Function Assessment Scale (SSA), Functional Oral Intake Scale (FOIS) and M.D.Anderson Dysphagia Inventory (MDADI) were used for evaluation before intervention, and two weeks, four weeks and eight weeks after intervention. ResultsFor scores of SSA , the main effects of group (F = 150.190, P < 0.001, η2p = 0.641) and time (F = 230.870, P < 0.001, η2p = 0.733), as well as the interaction effect (F = 16.910, P < 0.001, η2p = 0.168) were all significant. For scores of FOIS, the main effects of group (F = 59.601, P < 0.001, η2p = 0.415) and time (F = 89.464, P < 0.001, η2p = 0.516), as well as the interaction effect (F = 7.990, P < 0.001, η2p = 0.087) were all significant. For scores of MDADI, the main effects of group (F = 33.133, P < 0.001, η2p = 0.283) and time (F = 49.650, P < 0.001, η2p = 0.371), as well as the interaction effect (F = 3.224, P = 0.023, η2p = 0.037) were all significant. ConclusionVirtual reality biofeedback training combined with oral localization therapy could improve the swallowing function, oral feeding ability and overall quality of life of patients with dysphagia after oral cancer surgery.
9.The Prospect of Trimethylamine N-oxide Combined With Short-chain Fatty Acids in Atherosclerosis Risk Prediction
Zhi-Chao SHI ; Xu-Ping TIAN ; Si-Yi CHEN ; Shi-Guo LIU
Progress in Biochemistry and Biophysics 2026;53(2):404-417
Atherosclerosis (AS), the primary pathological contributor to cardiovascular diseases (CVDs), has increasingly affected younger populations due to modern dietary habits and sedentary lifestyles. Current diagnostic modalities, including ultrasound, MRI, and CT, primarily identify advanced lesions and inadequately evaluate plaque vulnerability, thereby hindering early detection. Conventional treatments, which involve long-term medications associated with side effects such as hepatic injury and surgical interventions that carry risks of restenosis and hemorrhage, underscore the urgent need for non-invasive, cost-effective early diagnostic methods and targeted therapies. Gut microbiota metabolites are pivotal in AS pathogenesis, with trimethylamine N-oxide (TMAO) and short-chain fatty acids (SCFAs) serving as functionally opposing biomarkers. TMAO is produced when gut bacteria, specifically Firmicutes and Proteobacteria, metabolize dietary choline and carnitine into trimethylamine (TMA), which the liver subsequently converts to TMAO via flavin-containing monooxygenase 3 (FMO3); TMAO is then excreted in urine. Variability in TMAO levels is influenced by marine food consumption and FMO3 modulation, which can be affected by genetics, age, and diet. Mechanistically, TMAO exacerbates AS by disrupting cholesterol metabolism, inducing endothelial dysfunction through the elevation of reactive oxygen species (ROS) and pro-inflammatory cytokines such as IL-6, and reducing nitric oxide levels. Additionally, TMAO activates NF-κB and NLRP3 pathways while enhancing platelet reactivity. Clinically, elevated TMAO levels correlate with early AS and serve as predictors of mortality in patients with stable coronary artery disease (CAD) and acute coronary syndrome (ACS), as well as major adverse cardiovascular events (MACE) in stroke patients. Conversely, SCFAs—namely acetate, propionate, and butyrate—are produced by gut bacteria such as Akkermansia muciniphila and Faecalibacterium prausnitzii through the fermentation of dietary fiber. These metabolites exert anti-AS effects: acetate aids in maintaining metabolic homeostasis; propionate protects endothelial function and reduces plaque area; and butyrate fortifies intestinal barriers while suppressing inflammation. Furthermore, SCFAs cross-regulate bile acid metabolism, thereby influencing TMAO levels, and antagonize the pro-inflammatory and lipid-disrupting effects of TMAO. The use of TMAO and SCFAs as standalone biomarkers is constrained by limitations. TMAO lacks specificity, while SCFA levels fluctuate based on gut microbiota and dietary intake. Traditional AS risk assessment tools, which include clinical indicators, imaging techniques, and single biomarkers such as CRP, LDL-C, and ASCVD scores, overlook gut metabolism and demonstrate inadequate performance in younger populations. This review advocates for an “antagonistic-complementary” combined strategy: utilizing acetate and TMAO for early AS, propionate and TMAO for progressive AS, and butyrate and TMAO for advanced AS, addressing endothelial dysfunction, lipid deposition, and plaque stability/thrombosis risk, respectively. For clinical application, standardization of detection methods is crucial; liquid chromatography-mass spectrometry (LC-MS) is the gold standard, necessitating a unified sample pretreatment protocol, such as extraction with 1% formic acid in methanol. Additionally, dried blood spots (DBS) facilitate non-invasive testing, provided that dietary controls are implemented prior to detection, including a 12-hour fast and avoidance of high-choline and high-fiber foods. Existing challenges encompass the absence of standardized systems, limited large-scale validation, and ambiguous interactions with conditions such as hypertension. The authors’ team has previously established connections between gut metabolites and AS, including the reduction of TMAO as a preventive measure for AS, thereby reinforcing this proposed strategy. Future research should prioritize standardization, the development of machine learning-optimized models, validation of interventions, and the exploration of multi-omics-based “gut microbiota-metabolite-vascular” networks. In conclusion, the combined detection of TMAO and SCFAs offers a novel framework for AS risk assessment, facilitating early diagnosis and targeted interventions while enhancing the integration of gut metabolism into cardiovascular disease management.
10.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.

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