BACKGROUND:Parkinson's disease is a multifactorial neurological disorder characterized by progressive loss of dopaminergic neurons,and dimethyl fumarate(DMF)has potent neuroprotective and immunomodulatory effects in neurodegenerative diseases. OBJECTIVE:To explore the neuroprotective mechanism of DMF in a mouse model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced Parkinson's disease. METHODS:Twenty-four C57BL/6 mice were selected and randomly divided into control group,model group,low-dose DMF,and high-dose DMF groups.An animal model of Parkinson's disease was established in the latter three groups by intraperitoneal injection of 30 mg/kg MPTP,once a day for 5 consecutive days.Intragastric administration was given 30 minutes after each injection of MPTP.Mice in the low-dose DMF group(30 mg/kg)and high-dose DMF group(50 mg/kg)were intragastrically administered once a day for 7 consecutive days.The control and model groups were initially administered the same dose of normal saline.Behavioral testing,western blot,oxidative stress marker detection,and immunohistochemical staining were used to analyze the regulatory effects of DMF on oxidative stress and Keap1/Nrf2 signaling pathway in MPTP-induced Parkinson's disease mice,as well as the protective mechanism of DMF on degeneration of dopamine neurons. RESULTS AND CONCLUSION:Compared with the model group,mice in the low-dose DMF group exhibited significant improvements in motor retardation and postural imbalance(P<0.01),with even more remarkable improvements observed in the high-dose DMF group(P<0.01).Compared with the control group,the model group showed a significant increase in the oxidative stress marker malondialdehyde and a decrease in superoxide dismutase expression(P<0.01).Compared with the model group,the low-dose DMF group reduced malondialdehyde production and increased superoxide dismutase expression(P<0.01),and similar improvements were observed in the high-dose DMF group(P<0.01).Immunohistochemical and western blot assays demonstrated a significant decrease in the number of dopaminergic neurons and tyrosine hydroxylase protein expression in the substantia nigra of mice in the model group compared with the control group(P<0.01).However,in the low-dose DMF group,there was an increase in the number of dopaminergic neurons and tyrosine hydroxylase protein expression in the substantia nigra(P<0.01),with even more significant improvements in the high-dose DMF group(P<0.01).Western blot results revealed that the model group exhibited elevated Keap1 protein expression and decreased Nrf2 protein expression.In contrast,the DMF groups showed reduced Keap1 protein expression and increased Nrf2 protein expression compared to the model group(P<0.01).To conclude,DMF regulates the Keap1/Nrf2 pathway in the substantia nigra of mice with Parkinson's disease,and this regulatory effect is positively correlated with the dose of DMF(P<0.01).Therefore,we infer that DMF exerts neuroprotective effects through the Keap1/Nrf2 signaling pathway.

BACKGROUND:Ligament flavum hypertrophy is the main cause of lumbar spinal stenosis,which is the result of multiple pathological factors working together.Currently,the molecular mechanism and pathway of action of ligament flavum hypertrophy are unclear,and there is a lack of effective non-surgical treatment options. OBJECTIVE:To investigate the molecular mechanisms of ligament flavum hypertrophy using methylation sequencing and transcriptome integration analysis methods. METHODS:Five normal ligament flavum tissue samples and five hypertrophic ligament flavum tissue samples were collected.Abnormal methylation sites and methylation status were recorded by methylation sequencing and abnormally expressed genes were recorded by transcriptome integration analysis.The genes that showed a negative correlation between methylation level and expression level at the intersection of the two were selected.GO and KEGG enrichment analyses were used to study the major functional pathways and molecular functions of differentially expressed genes.Key genes regulating ligamentum flavum hypertrophy were screened using protein-protein interaction analysis. RESULTS AND CONCLUSION:Methylation sequencing of the two groups of the ligament flavum showed 37 173 hypermethylation sites and 10 583 low methylation sites.Transcriptome integration analysis found 720 abnormally expressed genes,of which 463 were upregulated and 257 were down-regulated.There were 383 overlapping genes,of which 192 genes showed a negative correlation between the methylation level and the expression level.GO functional pathway analysis results showed that molecular function was enriched to 10 terms,cellular component was enriched to 15 terms,and biological process(BP)was enriched to 30 terms.The results of KEGG pathway enrichment analysis showed that 192 genes were mainly enriched to 9 pathways,such as PI3K-Akt signaling pathway,Rap1 signaling pathway,and focal adhesion signaling pathway.The protein-protein interaction analysis identified five genes,PPARG,EGFR,CNR1,TNF and COL11A2,which may be the key genes that regulate ligamentum flavum hypertrophy,and they can influence the occurrence and development of ligamentum flavum hypertrophy mainly through the regulation of tissue fibrosis,cell proliferation and differentiation,inflammatory factor levels,and collagen fiber expression.

BACKGROUND:Fibromyalgia syndrome,as a common rheumatic disease,is related to central sensitization and immune abnormalities.However,the specific mechanism has not been elucidated,and there is a lack of specific diagnostic markers.Exploring the possible pathogenesis of this disease has important clinical significance. OBJECTIVE:To screen the potential diagnostic marker genes of fibromyalgia syndrome and analyze the possible immune infiltration characteristics based on bioinformatics methods,such as weighted gene co-expression network analysis(WGCNA),and machine learning. METHODS:Gene expression profiles in peripheral serum of fibromyalgia syndrome patients and healthy controls were obtained from the gene expression omnibus(GEO)database.The differentially co-expressed genes were screened in the expression profile by differential analysis and WGCNA analysis.Least absolute shrinkage and selection operator(LASSO)and support vector machine-recursive feature elimination(SVM-RFE)machine learning algorithm were further used to identify hub biomarkers,and draw receiver operating characteristic curve(ROC)to evaluate the accuracy of diagnosing fibromyalgia syndrome.Finally,single sample gene set enrichment analysis(ssGSEA)and gene set enrichment analysis(GSEA)were used to evaluate the immune cell infiltration and pathway enrichment in patients with fibromyalgia syndrome. RESULTS AND CONCLUSION:Eight down-regulated differentially expressed genes(DEGs)were obtained after differential analysis of the GSE67311 dataset according to the conditions of log2|(FC)|>0 and P<0.05.After WGCNA analysis,497 genes were included in the module(MEdarkviolet)with the highest positive correlation(r=0.22,P=0.04),and 19 genes were included in the module(MEsalmon2)with the highest negative correlation(r=-0.41,P=6×10-5).After intersecting DEGs and the module genes of WGCNA,seven genes were obtained.Four genes were screened out by LASSO regression algorithm and five genes were screened out by SVM-RFE machine learning algorithm.After the intersection of the two,three core genes were identified,which were germinal center associated signaling and motility like,integrin beta-8,and carboxypeptidase A3.The areas under the ROC curve of the three core genes were 0.744,0.739,and 0.734,respectively,indicating that they have good diagnostic value and can be used as biomarkers for fibromyalgia syndrome.The results of immune infiltration analysis showed that memory B cells,CD56 bright NK cells,and mast cells were significantly down-regulated in patients with fibromyalgia syndrome compared with the control group(P<0.05),and were significantly positively correlated with the above three biomarkers(P<0.05).The enrichment analysis suggested that there were nine fibromyalgia syndrome enrichment pathways,mainly related to olfactory transduction pathway,neuroactive ligand-receptor interaction,and infection pathway.The above results showed that the occurrence and development of fibromyalgia syndrome are related to the involvement of multiple genes,abnormal immune regulation,and multiple pathways imbalance.However,the interactions between these genes and immune cells,as well as their relationships with various pathways need to be further investigated.

BACKGROUND:It has been found that internal factors such as anatomical structure,hormone level and neuromuscular function of athletes are closely related to the risk of anterior cruciate ligament injuries,and external factors such as the material of the playing field also become one of the risk factors affecting the occurrence of non-contact anterior cruciate ligament injuries,but they are relatively under-attended in the current studies. OBJECTIVE:To explore effects of artificial turf versus natural grass on the biomechanical performance of the lower limbs in young females during jump-landing. METHODS:According to the test needs,artificial turf and natural grass in accordance with the standards of GB/T 20033.3-2006 and GB/T 19995.1-2005 were leveled and fixed on two three-dimensional force measuring platforms.Twenty-one young females were voluntarily recruited and completed the jump-landing task on the artificial turf and natural grass.Subjects stood on the steps and then jumped forward,jumped down to the force measuring platform and immediately jumped with full force to the force measuring platform again.The two landings were required to fall to the two force measuring platforms,and the whole jumping action was considered successful without any pause.The kinematic,kinetic and electromyographic data of the lower limbs during the landing process were collected synchronously to compare and analyze the differences between the two. RESULTS AND CONCLUSION:In terms of kinetics,posterior and vertical ground reaction force at the initial landing moment during jump-landing on the natural grass were significantly lower than those on the artificial turf(P＜0.05,P＜0.01),as well as at the peak ground reaction force moment(P＜0.05,P＜0.05).Additionally,the knee flexion moment when jump-landing on the natural grass was higher than that on the artificial turf(P＜0.01).In terms of electromyography,within 100 ms after the initial landing moment,the electromyography activity levels of medial femoris muscle,lateral femoris muscle and anterior tibialis muscle when jump-landing on the natural grass were significantly lower than those on the artificial turf(P＜0.05,P＜0.01,P＜0.05).To conclude,compared with the natural grass,jump-landing on the artificial turf leads to an change in biomechanical performance that will cause an increase in anterior cruciate ligament tension.

BACKGROUND:Osteosarcoma has a complex pathogenesis and a poor prognosis.While advancements in medical technology have led to some improvements in the 5-year survival rate,substantial progress in its treatment has not yet been achieved. OBJECTIVE:To screen key molecular markers in osteosarcoma,analyze their relationship with osteosarcoma treatment drugs,and explore the potential disease mechanisms of osteosarcoma at the molecular level. METHODS:GSE99671 and GSE284259(miRNA)datasets were obtained from the Gene Expression Omnibus database.Differential gene expression analysis and Weighted Gene Co-expression Network Analysis(WGCNA)on GSE99671 were performed.Functional enrichment analysis was conducted using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes separately for the differentially expressed genes and the module genes with the highest positive correlation to the disease.The intersection of these module genes and differentially expressed genes was taken as key genes.A Protein-Protein Interaction network was constructed,and correlation analysis on the key genes was performed using CytoScape software,and hub genes were identified.Hub genes were externally validated using the GSE28425 dataset and text validation was conducted.The drug sensitivity of hub genes was analyzed using the CellMiner database,with a threshold of absolute value of correlation coefficient|R|>0.3 and P<0.05. RESULTS AND CONCLUSION:(1)Differential gene expression analysis identified 529 differentially expressed genes,comprising 177 upregulated and 352 downregulated genes.WGCNA analysis yielded a total of 592 genes with the highest correlation to osteosarcoma.(2)Gene Ontology enrichment results indicated that the development of osteosarcoma may be associated with extracellular matrix,bone cell differentiation and development,human immune regulation,and collagen synthesis and degradation.Kyoto Encyclopedia of Genes and Genomes enrichment results showed the involvement of pathways such as PI3K-Akt signaling pathway,focal adhesion signaling pathway,and immune response in the onset of osteosarcoma.(3)The intersection analysis revealed a total of 59 key genes.Through Protein-Protein Interaction network analysis,8 hub genes were selected,which were LUM,PLOD1,PLOD2,MMP14,COL11A1,THBS2,LEPRE1,and TGFB1,all of which were upregulated.(4)External validation revealed significantly downregulated miRNAs that regulate the hub genes,with hsa-miR-144-3p and hsa-miR-150-5p showing the most significant downregulation.Text validation results demonstrated that the expression of hub genes was consistent with previous research.(5)Drug sensitivity analysis indicated a negative correlation between the activity of methotrexate,6-mercaptopurine,and pazopanib with the mRNA expression of PLOD1,PLOD2,and MMP14.Moreover,zoledronic acid and lapatinib showed a positive correlation with the mRNA expression of PLOD1,LUM,MMP14,PLOD2,and TGFB1.This suggests that zoledronic acid and lapatinib may be potential therapeutic drugs for osteosarcoma,but further validation is required through additional basic experiments and clinical studies.

BACKGROUND:In recent years,with the rapid development of biomedicine,the study of brain aging and exosomes has attracted more and more attention,but there is no bibliometrics analysis in this field. OBJECTIVE:To objectively analyze domestic and foreign literature on brain aging and exosomes in the past 15 years,to summarize the research status,hot spots,and development trends in this field. METHODS:Using the core database of Web of Science as a search platform,we downloaded the literature on brain aging and exosomes published from the establishment of the database to December 28,2022,and analyzed the data from the aspects of country or region,institution,author,keywords,and co-cited literature using CiteSpace 6.1.R6 visualization software. RESULTS AND CONCLUSION:A total of 1 045 research articles were included,and the number of publications on brain aging and exosomes research both domestically and internationally was showing an increasing trend year by year.The United States ranked first with 429 papers,and China ranked second with 277 papers.Louisiana State University ranked first with 16 articles.Professor Lukiw Walter J from Louisiana State University in the United States was the author with the highest number of publications,and Professor Bartel DP from the Massachusetts Institute of Technology was the author with the most citations.The most prolific Journal was the International Journal of Molecular Sciences.Alzheimer's disease,microRNA,gene expression,extracellular vesicles,exosomes,oxidative stress,and biomarkers are the most relevant terms.According to the research on hot topics,biomarkers have become a new research hotspot.The above results indicate that the research on brain aging and exosomes has gradually increased in the past 15 years.The research direction has gradually shifted from the initial exploration of the expression of miRNAs in central nervous system diseases related to brain aging to the search for biomarkers that can identify and diagnose neurodegenerative diseases.The study of exocrine miRNAs to protect central nervous system from damage has emerged as promising therapeutic strategy.

BACKGROUND:Chondrocyte apoptosis is an important factor in the development of osteoarthritis,and Complanatoside A has a flavonoid effect,which can inhibit apoptosis of various cells,but its effect on chondrocyte apoptosis and the mechanism of action are not clear. OBJECTIVE:To investigate the intrinsic association and mechanism of Complanatoside A in chondrocyte apoptosis based on the Wnt/β-catenin signaling pathway. METHODS:(1)The cartilage tissues of the femur and tibia transected during knee arthroplasty were collected,and chondrocytes were isolated,cultured in vitro,and identified.(2)Cell counting kit-8 was used to detect the optimal intervention concentration of Complanatoside A in the concentration range of 0-160 μmol/L.(3)Chondrocytes were divided into blank group,sodium nitroprusside(1.5 mmol/L)-induced group,and sodium nitroprusside(1.5 mmol/L)+Complanatoside A(5 μmol/L)group.The viability and apoptosis rate of the cells in each group were detected by cell counting kit-8 and flow cytometry.The expression of type Ⅱ collagen and SOX9 was detected by immunofluorescence staining.The expression of apoptosis-related proteins and Wnt/β-catenin pathway proteins was detected by western blot assay. RESULTS AND CONCLUSION:The cells extracted in vitro were cultured and stained,and were clearly identified as chondrocytes.Complanatoside A had no obvious cytotoxicity to chondrocytes in the concentration range of 0-80 μmol/L,and significantly improved the chondrocyte viability in the concentration range of 2.5-10 μmol/L,especially when the concentration was 5 μmol/L.The apoptotic rate of chondrocytes was higher in the sodium nitroprusside-induced group than the blank control group,while the apoptotic rate was lower in the sodium nitroprusside+Complanatoside A group than the sodium nitroprusside-induced group.The fluorescence intensity of type Ⅱ collagen and SOX9 in chondrocytes was weaker in the sodium nitroprusside-induced group than the blank control group,while the fluorescence intensity of type Ⅱ collagen and SOX9 in the sodium nitroprusside+Complanatoside A group was higher than that of the sodium nitroprusside-induced group.In the sodium nitroprusside-induced group,the protein expression of Bax,Caspase-3,matrix metalloproteinase 13,Wnt3a,Wnt5a and β-catenin was higher than that of the blank control group,while the protein expression of Bcl-2 was lower than that of the blank control group.In the sodium nitroprusside+Complanatoside A group,except for the protein expression of Bcl-2 which was higher than that of the sodium nitroprusside-induced group,the expression of the other aforementioned proteins was lower than that of the sodium nitroprusside-induced group.To conclude,Complanatoside A has a certain inhibitory effect on chondrocyte apoptosis,which could regulate apoptosis-related proteins and promote the expression of chondrocyte regulatory factors,and presumably might play a role through inhibiting the Wnt/β-catenin signaling pathway.

BACKGROUND:The mechanisms underlying the occurrence of pressure injuries are complex,and it is not entirely clear which factors play a central role in the development of pressure injuries and how these factors operate. OBJECTIVE:To investigate the relationship between Piezo-type mechanosensitive ion channel component 1(Piezo1)and the occurrence of pressure injuries. METHODS:(1)Cellular experiment:Human immortalized keratinocytes(HaCaT)were treated with Yoda1,a Piezo1 agonist,at different concentrations.Cell viability,calcium ion influx,Piezo1,and apoptosis-related protein expression were detected.(2)Animal experiment:Twelve Sprague-Dawley rats were randomly divided into a control group and three experimental groups,with three rats in each group.The control group was not subjected to pressure,while in the three experimental groups,magnets with a thickness of 1,2,and 3 mm were used to press on both sides of the rats'back for 1 hour,respectively,to establish the animal models of pressure injuries.After modeling,all traumatic tissues were excised and subjected to hematoxylin-eosin,Masson,immunofluorescence staining and western blot assay. RESULTS AND CONCLUSION:Cellular experiments:The results of live/dead cell staining showed that HaCaT cell apoptosis increased with the increase of Yoda1 concentration(0,2.5,5,and 10 μmol/L),and calcium ion influx increased with the increase of Yoda1 concentration(0,5,and 10 μmol/L),as well as with the prolongation of treatment time.Western blot assay results showed an increase in the expression of BAX,TG2,and PIEZO1 and a decrease in the expression of the expression of Bcl-2 protein in HaCaT cells in 5 and 10 μmol/L Yoda1 groups compared with the control group(0 μmol/L Yoda1).Animal experiments:The results of hematoxylin-eosin and Masson staining showed that the skin structure of the three experimental groups was damaged at the compression site,there was subcutaneous fat liquefaction and necrosis,and collagen was sparse and disorganized,and damage to the skin structure at the compression site was aggravated with the increase of magnet thickness.Immunofluorescence staining and western blot results showed that compared with the control group,the expression of BAX,TG2,Yap1 and PIEZO1 proteins was elevated,and the expression of Bcl-2 proteins was lowered in the three experimental groups.Moreover,the expression of related proteins showed more significant changes with the increase of magnet thickness(pressure).To conclude,skin compression activates PIEZO1,leading to a significant influx of calcium ions.As the pressure increases,this ultimately results in cell apoptosis due to calcium overload.

BACKGROUND:Chronic myofascial trigger points can identify differential metabolite changes through non targeted metabolomics techniques,helping to understand and further explore the pathophysiological processes and pathogenesis of chronic myofascial trigger points from the perspective of endogenous small molecule metabolites. OBJECTIVE:To investigate potential biomarkers and related metabolic pathways based on urine metabolomics in the rat model of chronic myofascial trigger points. METHODS:Sixteen Sprague-Dawley rats were randomly divided into a model group and a normal group.The model group was used to establish a chronic myofascial trigger point animal model by combining blunt hitting with centrifugal exercise(treadmill slope:-16°,running speed:16 m/min,training time:90 minutes each),once a week for 8 continuous weeks,with 4 weeks off.After 12 weeks of modeling,the metabolic cage method was used to collect urine from rats at 24 hours after modeling.Liquid chromatography-mass spectrometry non-targeted metabolomics technology was used to detect metabolic profiles in the urine samples,screen common differential metabolites,and conduct bioinformatics analysis. RESULTS AND CONCLUSION:Compared with the normal group,there were 32 differential metabolic markers in the model group,of which 21 were upregulated and 11 were downregulated.A total of 14 differential metabolites were identified as potential biomarkers based on the value of variable important in projection greater than 3.The enrichment analysis of the Kyoto Encyclopedia of Genes and Genomes indicated that the formation of chronic myofascial trigger points is closely related to metabolic pathways such as primary bile acid biosynthesis and arachidonic acid metabolism.

BACKGROUND:Currently,numerous experiments delve into the intricate anatomy and biomechanical behavior of distinct segments of the supraspinatus muscle.However,the impact of shoulder joint stress resulting from damage to various regions of this muscle remains a scarcely explored domain.Understanding the repercussions of supraspinatus muscle injuries across different regions on the stress distribution and magnitude of articular cartilage and the glenoid is crucial for providing some theoretical support for clinical diagnosis and treatment. OBJECTIVE:To ascertain the maximum stress values by simulating different degrees of supraspinatus muscle rupture on the humeral cartilage surface,glenoid lip,and glenoid cartilage joint surface using three-dimensional finite element software. METHODS:Normal and healthy shoulder joint CT or MRI scans were processed through Mimics and Geomagic to extract molds.Subsequently,models were constructed via Solidworks.Varying degrees of supraspinatus muscle damage were simulated for each model to mimic fractures in different regions.Finally,Ansys,mechanical software,was employed for three-dimensional finite element biomechanical analysis,calculating stress values for the humeral cartilage surface,glenoid lip,and glenoid cartilage joint surface. RESULTS AND CONCLUSION:(1)With worsening degrees of supraspinatus muscle injury,the stress on the shoulder joint cartilage surface and glenoid lip escalated.(2)Among various regions,the anterior part of the supraspinatus muscle exhibited paramount significance.(3)While supraspinatus muscle fractures of differing degrees impacted the magnitude of cartilage stress on the glenoid labial surface,the stress distribution remained constant.(4)It is indicated that during the initial stages of horizontal abduction of the shoulder joint,the anterior region assumes a pivotal role,followed by the posterior deep region.Injury to the anterior part of the supraspinatus muscle leads to a significant surge in stress within the shoulder joint's soft tissue,potentially causing damage to the top of the glenoid lip and the anterior part of the glenoid cartilage.