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:Knee osteoarthritis(KOA)is a common chronic inflammatory disease that causes damage to joint cartilage and surrounding tissues.Immune cells play an important role in the immune-inflammatory response in knee osteoarthritis,but the specific mechanisms involved are still not fully understood. OBJECTIVE:To evaluate the potential causal relationship between 731 immune cell phenotypes and the risk of knee osteoarthritis using Mendelian randomization. METHODS:Summary statistics of genome-wide association studies(GWAS)for 731 immune cell phenotypes(from GCST0001391 to GCST0002121)obtained from the GWAS catalog and GWAS data for knee osteoarthritis from the IEUGWAS database(ebi-a-GCST007090)were used.Inverse variance-weighted method,MR-Egger regression,weighted median method,weighted mode method,and simple mode method were employed to investigate the causal relationship between immune cells and knee osteoarthritis.Sensitivity analyses were conducted to assess the reliability of the Mendelian randomization results.Reverse Mendelian randomization analysis was also performed using the same methods. RESULTS AND CONCLUSION:The forward MR analysis indicated significant causal relationships(FDR<0.20)between knee osteoarthritis and four immune cell phenotypes,namely CD27 on CD24+CD27+in B cells(OR=1.026,P=0.000 26,Pfdr=0.18),CD33 on CD33dim HLA DR-in myeloid cells(OR=1.014,P=0.000 50,Pfdr=0.18),and CD45RA+CD28-CD8br%CD8br in Treg cells(OR=1.001,P=0.000 78,Pfdr=0.18),and PDL-1 on monocytes in mononuclear cells(OR=0.952,P=0.000 98,Pfdr=0.18).These immune cell phenotypes showed direct positive or negative causal associations with the risk of knee osteoarthritis.Reverse Mendelian randomization analysis revealed no significant causal relationships(FDR<0.20)between knee osteoarthritis as exposure and any of the 731 immune cell phenotypes.The results of sensitivity analysis show that the P-values of the Cochran's Q test and the MR-Egger regression method for bidirectional Mendelian randomization were both greater than 0.05,indicating that there is no significant heterogeneity and pleiotropy in the causal effect analysis between immune cell phenotypes and knee osteoarthritis.To conclude,there may be four potential causal relationships between immune cell phenotypes,such as CD27 on CD24+CD27+cells,CD33 on CD33dim HLA DR-cells,CD45RA+CD28-CD8br%CD8br cells,and PDL-1 on monocytes,and knee osteoarthritis.These findings provide valuable clues for studying the biological mechanisms of knee osteoarthritis and exploring early prevention and treatment strategies.They also offer new directions for the development of intervention drugs.

BACKGROUND:Studies have shown that mitochondrial oxidative stress has an important role in the development of knee osteoarthritis,and Hemin can regulate the expression of mitochondria-related proteins. OBJECTIVE:To study the regulatory effect of Hemin on oxidative stress in mouse chondrocytes and its interventional effect and mechanism in knee osteoarthritis. METHODS:(1)In vitro cell experiment:Primary chondrocytes from C57BL/6 mice were extracted and induced with 10 ng/mL interleukin-1β to construct an in vitro chondrocyte model of osteoarthritis.The optimal concentration of Hemin(0,1,10,20,40,80,and 160 μmol/L)for the intervention in mouse chondrocytes was determined by cell counting kit-8 method.Chondrocytes were randomly divided into control group,model group(interleukin-1β)and Hemin group(interleukin-1β+Hemin).Reactive oxygen species,mitochondrial membrane potential and apoptosis of chondrocytes in each group were detected.(2)In vivo experiment:Adult C57BL/6 mice were randomly divided into normal group,model group(osteoarthritis)and Hemin group(osteoarthritis+Hemin),with eight mice in each group.After 4 weeks of Hemin treatment,the behavioral test and histopathological observation of the knee joint were performed in each group.Changes in extracellular matrix-related protein expression and apoptosis in chondrocytes and the expression level of Nrf2/HO-1 protein in cartilage tissue were detected. RESULTS AND CONCLUSION:In vitro experiment:the optimal concentration of Hemin on primary chondrocytes was 40 μmol/L.Compared with the model group,the level of reactive oxygen species was significantly reduced,the mitochondrial membrane potential was significantly improved,and the apoptosis of chondrocytes was reduced in the hemin-treated interleukin-1β-induced chondrocytes.In vivo experiment:After 4 weeks of treatment,compared with the model group,the lower limb function of mice in the Hemin group was significantly improved,the histopathological score was significantly improved,and the apoptosis of knee chondrocytes was significantly reduced.All these findings indicate that Hemin can alleviate oxidative stress,restore mitochondrial function and reduce apoptosis in mouse chondrocytes induced by interleukin-1β.Hemin can improve extracellular matrix degradation,promote chondrocyte anabolism,reduce catabolism and reduce chondrocyte apoptosis in knee osteoarthritis.It may act by activating the chondrocyte Nrf2/HO-1 signaling pathway in the inflammatory environment.

BACKGROUND:Liuwei Dihuang Wan takes"three tonifying and three reducing effects"as its compatibility feature to nourish yin and tonify the kidneys,while Zuogui Wan takes"seeking yin in yang"as its compatibility feature to nourish yin and tonify the kidneys by promoting yang.Both of them belong to the same method of nourishing yin and tonifying the kidneys,and have better curative effects at the symptomatic and cellular molecular levels. OBJECTIVE:To observe the effects of Liuwei Dihuang Wan and Zuogui Wan in bone metabolism,and to explore their mechanism of action in the osteoprotegerin(OPG)/receptor activator of nuclear factor-κB ligand(RANKL)osteoblastic pathway. METHODS:Thirty-two Sprague-Dawley rats were randomized into model,Liuwei Dihuang Wan,Zuogui Wan,and sham operation group,with eight rats in each group.Osteoporosis models were prepared using removal of both ovaries in the first three groups.Starting at 30 days postoperatively,rats in the Liuwei Dihuang Wan group were gavaged with Liuwei Dihuang Wan 1.125 g/kg/d;rats in the Zuoqui Wan group were gavaged with Zuogui Wan 2.25 g/kg/d;and rats in the sham operation group and the model group were gavaged with saline 10 mL/kg/d.After 12 weeks of gavage,the rat tibia was taken to measure bone mineral density.The serum levels of estrogen,bone alkaline phosphatase,and cAMP/cGMP were measured using ELISA,and the expression of OPG/RANKL in the femur was detected using western blot. RESULTS AND CONCLUSION:Compared with the sham operation group,the model group showed a decrease in bone mineral density and levels of estrogen and bone alkaline phosphatase(P＜0.05)and an increase in cAMP/cGMP level(P＜0.05).Compared with the model group,the Liuwei Dihuang Wan group and the Zuogui Wan group significantly increased bone mineral density(P＜0.05)and bone alkaline phosphatase levels(P＜0.05);the Zuogui Wan group significantly decreased cAMP/cGMP levels(P＜0.05)and upregulated OPG expression(P＜0.05);the Liuwei Dihuang Wan group upregulated OPG expression and downregulated RANKL expression(P＜0.05);and both groups were unable to significantly increase estrogen levels(P＞0.05).To conclude,Zuogui Wan,which seeks yin from yang,can effectively increase the expression of OPG but cannot downregulate the expression of RANKL.However,Liuwei Dihuang Wan,which has three tonifying and three reducing effects,can bidirectionally regulate the expression of OPG and RANKL.This result suggests that Liuwei Dihuang Wan can significantly inhibit osteoclastic function compared with Zuogui Wan,and further research is needed to verify this conclusion.

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 repair process of myocardial injury involves complex cellular and molecular mechanisms,especially mitochondrial calcium homeostasis,macrophage autophagy and pyroptosis pathways.Traditional Chinese medicine(TCM)has shown significant clinical efficacy in improving myocardial injury,but its mechanism of action needs to be thoroughly investigated. OBJECTIVE:To investigate the role of mitochondrial calcium homeostasis-mediated macrophage autophagy and pyroptosis pathways in myocardial injury,and to summarize the progress of TCM in this field. METHODS:A computerized search was performed for relevant literature from the database inception to March 2024 in the Web of Science,PubMed and CNKI.The search terms were"mitochondrial calcium homeostasis,macrophage autophagy,macrophage pyroptosis,traditional Chinese medicine,myocardial injury,myocardial injury reperfusion"in Chinese and English.Through literature review,we analyzed the relationship between mitochondrial calcium homeostasis and macrophage autophagy and pyroptosis,explored the mechanism of their roles in myocardial injury,and summarized the pathways of multi-targeted,multi-pathway effects of TCM. RESULTS AND CONCLUSION:The maintenance of mitochondrial calcium homeostasis has been found to be closely related to the normal function of cardiomyocytes.Macrophages can participate in the repair process of myocardial injury through autophagy and pyroptosis pathways.Autophagy contributes to cell clearance and regulation of inflammatory response,while pyroptosis affects myocardial repair by releasing inflammatory factors.TCM regulates mitochondrial calcium homeostasis and macrophage function through multiple mechanisms.For example,astragalosid regulates calcium homeostasis by lowering mitochondrial membrane potential and inhibiting cytochrome C,and epimedium glycoside plays a role in reducing β-amyloid deposition.In addition,herbal compounds and single drugs promote myocardial repair by activating or inhibiting specific signaling pathways,such as PI3K/AKT and nuclear factor-κB signaling pathways.Future studies should focus on the interactions between mitochondrial calcium homeostasis,autophagy and pyroptosis pathways,as well as how TCM can exert therapeutic effects through these pathways to provide new strategies and drugs for the treatment of myocardial injury.

BACKGROUND:Osteoporotic fracture is the most serious complication of osteoporosis.Previous studies have demonstrated that gut microbiota has a regulatory effect on skeletal tissue and that gut microbiota has an important relationship with osteoporotic fracture,but the causal relationship between the two is unclear. OBJECTIVE:To explore the causal relationship between gut microbiota and osteoporotic fractures using Mendelian randomization method. METHODS:The genome-wide association study(GWAS)datasets of gut microbiota and osteoporotic fracture were obtained from the IEU Open GWAS database and the Finnish database R9,respectively.Using gut microbiota as the exposure factor and osteoporotic fracture as the outcome variable,Mendelian randomization analyses with random-effects inverse variance weighted,MR-Egger regression,weighted median,simple model,and weighted model methods were performed to assess whether there is a causal relationship between gut microbiota and osteoporotic fracture.Sensitivity analyses were performed to test the reliability and robustness of the results.Reverse Mendelian randomization analyses were performed to further validate the causal relationship identified in the forward Mendelian randomization analyses. RESULTS AND CONCLUSION:The results of this Mendelian randomization analysis indicated a causal relationship between gut microbiota and osteoporotic fracture.Elevated abundance of Actinomycetales[odds ratio(OR)=1.562,95%confidence interval(CI):1.027-2.375,P=0.037),Actinomycetaceae(OR=1.561,95%CI:1.027-2.374,P=0.037),Actinomyces(OR=1.544,95%CI:1.130-2.110,P=0.006),Butyricicoccus(OR=1.781,95%CI:1.194-2.657,P=0.005),Coprococcus 2(OR=1.550,95%CI:1.068-2.251,P=0.021),Family ⅩⅢ UCG-001(OR=1.473,95%CI:1.001-2.168,P=0.049),Methanobrevibacter(OR=1.274,95%CI:1.001-1.621,P=0.049),and Roseburia(OR=1.429,95%CI:1.015-2.013,P=0.041)would increase the risk of osteoporotic fractures in patients.Elevated abundance of Bacteroidia(OR=0.660,95%CI:0.455-0.959,P=0.029),Bacteroidales(OR=0.660,95%CI:0.455-0.959,P=0.029),Christensenellacea(OR=0.725,95%CI:0.529-0.995,P=0.047),Ruminococcaceae(OR=0.643,95%CI:0.443-0.933,P=0.020),Enterorhabdus(OR=0.558,95%CI:0.395-0.788,P=0.001),Eubacterium rectale group(OR=0.631,95%CI:0.435-0.916,P=0.016),Lachnospiraceae UCG008(OR=0.738,95%CI:0.546-0.998,P=0.048),and Ruminiclostridium 9(OR=0.492,95%CI:0.324-0.746,P=0.001)would reduce the risk of osteoporotic fractures in patients.We identified 16 gut microbiota associated with osteoporotic fracture by the Mendelian randomization method.That is,using gut microbiota as the exposure factor and osteoporotic fracture as the outcome variable,eight gut microbiota showed positive causal associations with osteoporotic fracture and another eight gut microbiota showed negative causal associations with osteoporotic fracture.The results of this study not only identify new biomarkers for the early prediction of osteoporotic fracture and potential therapeutic targets in clinical practice,but also provide an experimental basis and theoretical basis for the study of improving the occurrence and prognosis of osteoporotic fracture through gut microbiota in bone tissue engineering.

BACKGROUND:Primary cortical neurons and microglial cells play a crucial role in exploring cell therapies for neurological disorders,and most of the current methods for obtaining the two types of cells are cumbersome and require separate extraction.It is therefore crucial to find a convenient and rapid method to extract both types of cells simultaneously. OBJECTIVE:To explore a novel method for simultaneous extraction of primary cortical neurons and microglial cells. METHODS:Newborn suckling SD rats were taken within 24 hours.The brain was removed and placed in a dish with DMEM,and the pia mater was removed for later use.Primary neurons were extracted from the same brain tissue,and then the remaining brain tissue was used to extract microglial cells.The whole process was performed on ice.Extraction and culture steps of primary cortical neurons:The cerebral cortex was taken 2.0-3.0 mm with forceps,and the tissue was digested with papain for 20 minutes.After aborting digestion,the blown tissue presented an adherent tissue suspension.The supernatant cell suspension was obtained,filtered,and dispensed into 15 mL centrifuge tubes.After centrifugation and re-suspension,the cells were inoculated onto 6-well plate crawls coated with L-polylysine.Neuronal morphology was observed at 1-day intervals,and staining could be performed for identification using immunofluorescence staining of MAP2 and β-Tubulin by day 7.Microglia extraction and culture steps:The remaining brain tissue at 8-10 mm thick was subjected to microglial cell extraction,digested by trypsin for 20 minutes.After digestion was stopped,the tissue was blown to a homogenate,and then the homogenate was transferred to the culture bottle for culture.On day 14,the culture flasks were sealed and subjected to constant temperature horizontal shaking for 2 hours.Microglial cells were shed in the supernatant.Purified microglial cells were taken and continued to be cultured for 3 days for identification by Iba1 immunofluorescence staining. RESULTS AND CONCLUSION:(1)After 24 hours of culture,the neurons were adherent to the wall,the cytosol was enlarged,and some neurons developed synapses.After 3 and 5 days of culture,the cytosol was further enlarged,and most of the neurons were in the form of synapses,and some neurons were growing in clusters.On day 7,neuronal synapses were prolonged and thickened,and they were connected with each other to form a network.The neurons were identified by β-Tubulin and MAP2 immunofluorescence staining.(2)The cells grew close to the wall on day 1 of culture.On days 3,5,and 7,the density of microglial cells was small,and the cell morphology was bright oval or round,but the cells basically grew in clumps on the upper layer of other cells.On day 10,the density of microglial cells increased significantly.On day 14,microglial cells grew in dense clumps on the upper layer of other cells,and then they could be isolated and purified.The isolated and purified cells were taken and re-cultured to day 3 and identified as microglial cells by Iba1 immunofluorescence;their purity was greater than 95%.(3)The results show that primary cortical neurons and microglial cells obtained by this method after extraction and culture are of high purity,good morphology,and high viability.

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,numerous studies have shown that autophagy and mitophagy play an important role in the regulation of bone metabolism.Under non-physiological conditions,mitophagy breaks the balance of bone metabolism and triggers metabolism disorders,which affect osteoblasts,osteoclasts,osteocytes,chondrocytes,bone marrow mesenchymal stem cells,etc. OBJECTIVE:To summarize the mechanism of mitophagy in regulating bone metabolic diseases and its application in clinical treatment. METHODS:PubMed,Web of Science,CNKI,WanFang and VIP databases were searched by computer using the keywords of"mitophagy,bone metabolism,osteoblasts,osteoclasts,osteocytes,chondrocytes,bone marrow mesenchymal stem cells"in English and Chinese.The search time was from 2008 to 2023.According to the inclusion criteria,90 articles were finally included for review and analysis. RESULTS AND CONCLUSION:Mitophagy promotes the generation of osteoblasts through SIRT1,PINK1/Parkin,FOXO3 and PI3K signaling pathways,while inhibiting osteoclast function through PINK1/Parkin and SIRT1 signaling pathways.Mitophagy leads to bone loss by increasing calcium phosphate particles and tissue protein kinase K in bone tissue.Mitophagy improves the function of chondrocytes through PINK1/Parkin,PI3K/AKT/mTOR and AMPK signaling pathways.Modulation of mitophagy shows great potential in the treatment of bone diseases,but there are still some issues to be further explored,such as different stages of drug-activated mitophagy,and the regulatory mechanisms of different signaling pathways.