BACKGROUND:The extracellular-regulated protein kinase 5(ERK5)signaling protein is essential for the survival of organisms,and resveratrol can promote osteoblast proliferation through various pathways.However,whether resveratrol can regulate osteoblast function through the ERK5 signaling protein needs further verification. OBJECTIVE:To explore the regulatory effect of ERK5 on the proliferation of MC3T3-E1 cells and related secreted proteins,and to further verify whether resveratrol can complete the above process by activating ERK5. METHODS:Mouse MC3T3-E1 preosteoblasts were treated with complete culture medium,XMD8-92(an ERK5 inhibitor),epidermal growth factor(an ERK5 activator),resveratrol alone,XMD8-92+EGF,and resveratrol+XMD8-92,respectively.Western blot assay was used to detect the expression of ERK5 and p-ERK5 proteins,proliferation-related proteins Cyclin D1,CDK4 and PCNA,and osteoblast-secreted proteins osteoprotegerin and receptor activator of nuclear factor-κB ligand in MC3T3-E1 cells of each group.The fluorescence intensity of ERK5,osteoprotegerin and receptor activator of nuclear factor-κB ligand in each group was detected by cell immunofluorescence staining,and cell proliferation was detected by EdU staining,respectively.The appropriate concentration and time of resveratrol intervention in MC3T3-E1 cells were determined by cell morphology observation and cell counting kit-8 assay. RESULTS AND CONCLUSION:The activation of ERK5 signaling protein could effectively promote the proliferation of MC3T3-E1 cells,up-regulate the osteoprotegerin/receptor activator of nuclear factor-κB ligand ratio.The appropriate concentration and time for resveratrol intervention in MC3T3-E1 cells was 5 μmol/L and 24 hours,respectively.Resveratrol could activate ERK5 signaling protein,thereby promoting osteoblast proliferation and up-regulating the osteoprotegerin/RANKL ratio.All these results indicate that resveratrol can promote the proliferation of MC3T3-E1 cells and up-regulate the osteoprotegerin/RANKL ratio by activating the ERK5 signaling protein.

BACKGROUND:Studies have shown that metformin has anti-inflammatory,anti-tumor,anti-aging and vasoprotective effects,and can inhibit the progression of osteoarthritis,but its specific mechanism of action remains unclear. OBJECTIVE:To investigate the mechanism of metformin on cartilage protection in a rat model of osteoarthritis. METHODS:Forty male Sprague-Dawley rats were randomly divided into four groups(n=10 per group):blank,control,sham-operated,and metformin groups.The blank group did not undergo any surgery.In the sham-operated group,the joint cavity was exposed.In the model group and the metformin group,the modified Hulth method was used to establish the osteoarthritis model.At 1 day after modeling,the rats in the metformin group were given 200 mg/kg/d metformin by gavage,and the model,blank,and sham-operated groups were given normal saline by gavage.Administration in each group was given for 4 weeks consecutively.Hematoxylin-eosin staining,toluidine blue staining,and safranin O-fast green staining were used to observe the morphological structure of rat knee joints.Immunohistochemical staining and western blot were used to detect the protein expression of SOX9,type Ⅱ collagen,a disintegrin and metalloproteinase with thrombospondin motifs 5(ADAMTS5),Beclin1,P62,phosphatidylinositol 3-kinase(PI3K),p-PI3K,protein kinase B(AKT),p-AKT,mammalian target of rapamycin(Mtor),and p-Mtor in rat cartilage tissue. RESULTS AND CONCLUSION:The results of hematoxylin-eosin,toluidine blue and safranin O-fast green staining showed smooth cartilage surface of the knee joints and normal histomorphology in the blank group and the sham-operated group,while in the model group,there was irregular cartilage surface of the knee joint and cartilage damage,with a decrease in the number of chondrocytes and the content of proteoglycans in the cartilage matrix.In the metformin group,there was a significant improvement in the damage to the structure of the cartilage in the knee joints of the rats,and the cartilage surface tended to be smooth,with an increase in the number of chondrocytes and the content of proteoglycans in the cartilage matrix.Immunohistochemistry staining and western blot results showed that compared with the control and sham-operated groups,the expression of SOX9,type Ⅱ collagen,and Beclin1 proteins in the cartilage tissue of rats in the model group was significantly decreased(P<0.05).Conversely,the expression of ADAMTS5,P62,as well as p-PI3K,p-AKT,and p-Mtor proteins was significantly increased(P<0.05).Furthermore,compared with the model group,the expression of SOX9,type Ⅱ collagen,and Beclin1 proteins in the cartilage tissue of rats in the metformin group was significantly increased(P<0.05),while the expression of ADAMTS5,P62,as well as p-PI3K,p-AKT,and p-Mtor proteins was significantly decreased(P<0.05).To conclude,Metformin can improve the autophagy activity of chondrocytes and reduce the degradation of cartilage matrix in osteoarthritis rats by inhibiting the activation of PI3K/AKT/Mtor signaling pathway,thus exerting a protective effect on articular cartilage.

BACKGROUND:Rheumatoid arthritis is an inflammatory disease.Many studies have shown that wogonin has a good anti-inflammatory effect on rheumatoid arthritis,but its exact efficacy and specific mechanism of action remain to be clarified. OBJECTIVE:To investigate the mechanism of wogonin ameliorating joint inflammation by regulating endoplasmic reticulum stress pathway in rats with collagen-induced arthritis. METHODS:(1)At the animal level:Female Wistar rats were divided into healthy control group,arthritis model group and wogonin treatment group.Rat models of arthritis in the latter two groups were established by subcutaneous injection of bovine type Ⅱ collagen and adjuvant.In the wogonin group,wogonin was given by gavage for 28 consecutive days after modeling.During this period,the rats in each group were weighed,and arthritis score and ankle swelling were measured every 7 days.After the experiment,the pathological changes of the joint were observed,the mRNA and protein levels of endoplasmic reticulum stress pathway GRP78 and CHOP were detected by qRT-PCR,western blot,and immunohistochemistry.(2)At the cellular level,cell counting kit-8 was used to detect the cytotoxic effect of wogonin on fibroblast-like synoviocytes from rats with collagen-induced arthritis.The fibroblast-like synoviocytes induced by thapsigargin were treated with different concentrations of wogonin.The levels of interleukin-1β and tumor necrosis factor-α in the cell supernatant were detected by ELISA,and the intracellular reactive oxygen species in each group were determined by DCFH-DA probe method.The mRNA and protein levels of GRP78,IRE1α,XBP1s and CHOP were detected by qRT-PCR and western blot,respectively. RESULTS AND CONCLUSION:Compared with the healthy control group,arthritis index score and ankle swelling degree in the arthritis model group were increased(P<0.01),synovial hyperplasia,inflammatory cell infiltration,cartilage destruction and bone erosion were observed in pathological sections,and the mRNA and protein expressions of GRP78 and CHOP in the ankle were significantly increased(P<0.01),which were mainly located in synovial tissue and articular surface.Compared with the arthritis model group,the arthritis index score and ankle swelling degree in the wogonin treatment group were decreased(P<0.05),synovial hyperplasia and the number of inflammatory cells were decreased,cartilage destruction and bone erosion were alleviated,the mRNA and protein expression levels of GRP78 and CHOP in the ankle were decreased(P<0.05),particularly in synovial tissue and on the articular surface.There was no significant difference in body mass among the three groups(P>0.05).In the cell experiment,200 μmol/L wogonin significantly reduced the survival rate of fibroblast-like synoviocytes(P<0.01).Compared with the blank control group,the levels of interleukin-1β,tumor necrosis factor-α,content of reactive oxygen species,and mRNA and protein expression of GRP78,IRE1α,XBP1s,and CHOP in the thapsigargin group were significantly increased(P<0.05);compared with the thapsigargin group,50 and 100 μmol/L wogonin significantly reduced the levels of interleukin-1β and tumor necrosis factor-α in the cell supernatant(P<0.05,P<0.01),and 100 μmol/L wogonin significantly reduced the content of reactive oxygen species(P<0.01)and down-regulated the mRNA and protein expression levels of GRP78,IRE1α,XBP1s and CHOP(all P<0.05).These results suggest that wogonin can effectively alleviate joint inflammatory responses in rats with collagen-induced arthritis,and the endoplasmic reticulum stress pathway may be the key target of its intervention.

BACKGROUND:Troxerutin has been found to have a significant ameliorative effect on brain disorders,but there are fewer studies on the effects of troxerutin on the treatment of cerebral infarction and on neuronal cells. OBJECTIVE:To investigate the mechanism by which troxerutin regulates nuclear factor-κB signaling pathway to reduce brain injury and neuronal apoptosis in cerebral infarction rats. METHODS:Fifty clean grade rats were randomized into healthy group,model group,and troxerutin+nuclear factor-κB agonist group,troxerutin group,and nuclear factor-κB inhibitor group.Except for the healthy group,all other groups were used to establish a rat model of cerebral infarction by arterial ligation.The healthy and model groups were treated once a day with an equal amount of physiological saline by gavage.The troxerutin+nuclear factor-κB agonist group was intervened with 72 mg/kg troxerutin by gavage+20 mg/kg RANK intraperitoneally.The troxerutin group was treated with 72 mg/kg troxerutin by gavage.The nuclear factor κB inhibitor group was intervened intraperitoneally with 120 mg/kg nuclear factor κB inhibitor pyrrolidine disulfiram.Administration in each group was given once a day for 30 continuous days.Zea-longa was used to detect neurological damage in rats,hematoxylin-eosin staining was used to observe pathological changes,TUNEL was used to detect neuronal apoptosis,and immunoblotting and PCR were used to detect the expression of nuclear factor-κB p65 and nuclear factor-κB p50 at protein and mRNA levels,respectively. RESULTS AND CONCLUSION:Compared with the healthy group,the neurological function score,neuronal apoptosis rate,nuclear factor-κB p65,nuclear factor-κB p50 mRNA and protein expression levels were elevated in the model group(P＜0.05).Compared with the model group,the neurological function score,neuronal apoptosis rate,nuclear factor-κB p65 and nuclear factor-κB p50 mRNA and protein expression levels were decreased in the troxerutin+nuclear factor-κB agonist group(P＜0.05).Compared with the troxerutin+nuclear factor-κB agonist group,the neurological function score,neuronal apoptosis rate,nuclear factor-κB p65 and nuclear factor-κB p50 mRNA and protein expression levels were reduced in the troxerutin group and nuclear factor-κB inhibitor group(P＜0.05).In addition,there was no difference between the troxerutin group and the nuclear factor-κB inhibitor group(P＞0.05).In the model group,there was a large number of cytoplasmic vacuolation,obvious edema and necrosis,and a large number of inflammatory cell infiltrations.In the troxerutin+nuclear factor-κB agonist,the swelling of brain tissue was reduced,and reticulate structures and condensed cells were reduced,still with some edema.In the troxerutin group and nuclear factor-κB inhibitor group,brain tissue swelling,neuronal edema degeneration,cytoplasmic vacuolation and neuronal nucleus consolidation were reduced,and the inflammatory cell infiltration was significantly decreased.To conclude,troxrutin can reduce the expression of neurological impairment,inhibit neuronal apoptosis and improve the pathological injury of brain tissue in rats with cerebral infarction,and its mechanism of action may be related to the modulation of nuclear factor-κB expression and related signaling pathways.

BACKGROUND:Flap transplantation technique is a commonly used surgical procedure for the treatment of severe tissue defects,but postoperative flap necrosis is easily triggered by ischemia-reperfusion injury.Therefore,it is still an important research topic to improve the survival rate of transplanted flaps. OBJECTIVE:To review the pathogenesis and latest treatment progress of flap ischemia-reperfusion injury. METHODS:CNKI,WanFang Database and PubMed database were searched for relevant literature published from 2014 to 2024.The search terms used were"flap,ischemia-reperfusion injury,inflammatory response,oxidative stress,Ca2+overload,apoptosis,mesenchymal stem cells,platelet-rich plasma,signaling pathways,shock wave,pretreatment"in Chinese and English.After elimination of irrelevant literature,poor quality and obsolete literature,77 documents were finally included for review. RESULTS AND CONCLUSION:Flap ischemia/reperfusion injury may be related to pathological factors such as inflammatory response,oxidative stress response,Ca2+overload,and apoptosis,which can cause apoptosis of vascular endothelial cells,vascular damage and microcirculation disorders in the flap,and eventually lead to flap necrosis.Studies have found that mesenchymal stem cell transplantation,platelet-rich plasma,signaling pathway modulators,shock waves,and pretreatment can alleviate flap ischemia/reperfusion injuries from different aspects and to varying degrees,and reduce the necrosis rate and necrosis area of the grafted flap.Although there are many therapeutic methods for skin flap ischemia/reperfusion injury,a unified and effective therapeutic method has not yet been developed in the clinic,and the advantages and disadvantages of various therapeutic methods have not yet been compared.Most of the studies remain in the stage of animal experiments,rarely involving clinical observations.Therefore,a lot of research is required in the future to gradually move from animal experiments to the clinic in order to better serve the clinic.

BACKGROUND:The absence of blood vessels in tendon tissue makes tendon repair challenging.Therefore,improving tendon healing and raising the efficacy of stem cell and other therapeutic cell transplantation after tendon damage have become hotspots for research in both clinical and scientific contexts. OBJECTIVE:The stem cells and gelatin microcarrier scaffold were joined to form tissue engineered stem cells.Human umbilical cord mesenchymal stem cells cultured in gelatin microcarriers were used to investigate the therapeutic impact and mode of action on tendinopathy healing in rats in vitro and In vivo. METHODS:(1)In vitro cell experiments:After seeding human umbilical cord mesenchymal stem cells with three-dimensional gelatin microcarriers,the cell vitality and survival were assessed.Human umbilical cord mesenchymal stem cells conventionally cultured were cultured as controls.(2)In vivo experiment:Adult SD rats were randomly assigned to normal group,tendinopathy group,2D group(tendinopathy+conventional culture of human umbilical cord mesenchymal stem cells),and 3D group(tendinopathy+gelatin microcarrier three-dimensional culture of human umbilical cord mesenchymal stem cells),with 6 rats in each group.Four weeks after therapy,animal behavior tests and histopathologic morphology of the Achilles tendon was examined. RESULTS AND CONCLUSION:(1)In vitro cell experiments:the seeded human umbilical cord mesenchymal stem cells on gelatin microcarriers showed high viability and as time went on,the stem cell proliferation level grew.Compared with the control group,3D stem cell culture preserved cell viability.(2)In vivo experiment:Following a 4-week treatment,the 3D stem cell culture group showed a significant improvement in both functional recovery of the lower limbs and histopathological scores when compared to the tendinopathy group.The 2D stem cell culture group also showed improvement in tendinopathy injury,but its effect is not as much as the 3D stem cell culture group.(3)The outcomes demonstrate that human umbilical cord mesenchymal stem cells cultured with three-dimensional gelatin microcarrier can promote the repair and regeneration of tendon injury tissue,and the repair effect is better than that of conventional human umbilical cord mesenchymal stem cells.

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:Ferroptosis is closely associated with the pathogenesis of ischemic stroke,and targeting ferroptosis is a promising regimen for the treatment of ischemic stroke,but the specific regulatory targets are unclear. OBJECTIVE:To screen ferroptosis-related characterized genes in ischemic stroke by bioinformatics and machine learning methods and validate them by cellular experiments to investigate the role of ferroptosis in ischemic stroke. METHODS:Eligible ischemic stroke-related datasets and ferroptosis expression datasets were selected based on GEO database and FerrDb database,and ferroptosis-related differential genes were screened by t-test.GO functional enrichment analysis with KEGG signaling pathway enrichment analysis was performed for ferroptosis-related differential genes.Characterized genes for ferroptosis in ischemic stroke were screened by PPI network analysis and machine learning.The reliability and biological functions of the characterized genes were explored using ROC analysis and GSEA analysis,followed by cell experiment.HT22 cells were divided into control and ischemic stroke groups.No intervention was made in the control group,and 0.1 mM H2O2 was added to the ischemic stroke group for 24 hours to simulate cellular oxidative stress injury and ferroptosis.The ferroptosis and the expression of characterized genes were verified by real-time fluorescence quantitative polymerase chain reaction(RT-PCR)and western blot assay. RESULTS AND CONCLUSION:(1)Forty-five ferroptosis-associated differential genes were obtained,and GO and KEGG enrichment analyses revealed that the differential genes were closely associated with oxidative stress,autophagy,ferroptosis,adipocytokine signaling pathway,and mitochondrial metabolism.(2)A total of one ferroptosis characterized gene,nuclear factor erythroid 2-related factor 2(NFE2L2),was identified by the MCODE plugin and cytoHubba plugin in the PPI network with the LASSO algorithm and SVM-RFE algorithm in machine learning.(3)Receiver operating characteristic curve analysis of NFE2L2 revealed that the diagnostic prediction models constructed in the training and validation sets had good accuracy and specificity.GSEA analysis of NFE2L2 revealed that the characterized gene was involved in the regulation of ischemic stroke pathogenesis through immunity,inflammatory response,amino acid metabolism,and neurofactor regulation.(4)RT-PCR and western blot analyses showed that the acyl coenzyme A synthetase long chain family,member 4(ACSL4)mRNA and protein expression levels were significantly higher in the ischemic stroke group compared with the control group(P<0.05),and the glutathione peroxidase 4(GPX4)mRNA and protein expression levels were significantly lower in the ischemic stroke group(P<0.05).Compared with the control group,the mRNA and protein expression levels of the characterized gene NFE2L2 were significantly higher in the ischemic stroke group(P<0.05).(5)It suggests that ischemic stroke is closely related to ferroptosis,and targeting the characterized gene NFE2L2 may provide certain ideas and directions for the study and treatment of ischemic stroke.

BACKGROUND:During tissue repair and regeneration,macrophages exhibit multiple activities such as promoting inflammation,anti-inflammation,fibrosis,and wound healing at various stages of tissue damage.The heterogeneity and balanced polarization of macrophages are decisive in organ repair. OBJECTIVE:To explore the research hotspots and development trends in the field of macrophage polarization in tissue repair through visualization analysis methods,as well as the research level of global scientific and clinical workers in this field. METHODS:Using bibliometric analysis methods,this study employed Citespace literature visualization analysis software and VOSviewer tools,retrieving related literature from 2013 to 2023 in the Web of Science Core Collection's Science Citation Index Expanded(SCI-Expanded)and Social Sciences Citation Index Expanded(SSCI-Expanded)databases.The analysis results were presented in a dynamic map format,revealing the main trends and focuses of the research. RESULTS AND CONCLUSION:The number of publications in this field had dramatically increased from 2013 to 2023,with a significant rise starting in 2017.Chinese researchers had the highest number of publications,with 642 papers,while American researchers began focusing on this field early on.Professor Elisseeff Hennifer H had made a substantial contribution to the research in this area.Shanghai Jiao Tong University had produced the most publications.In recent years,keywords such as"hyaluronic acid"and"regulation"had been prevalent.Macrophage polarization research in tissue repair primarily concentrates on its multifunctional regulatory mechanisms,interactions with other cell types,and its behavior under specific pathological conditions.The main research areas include the role of macrophages in wound healing,cardiovascular diseases,chronic inflammation,tumor microenvironments,and regenerative medicine.A deeper understanding of the multifunctionality and polarization mechanisms of macrophages can lead to the development of new therapeutic strategies to enhance tissue repair and regeneration,thereby improving patient treatment outcomes.

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.