BACKGROUND:Arthroscopic anchor repair has become the main treatment method for rotator cuff tears at present.Among them,the insertion status of the anchor is a key factor in the success or failure of the operation.However,currently,the impact of the insertion depth of the anchor on the stress of the bone tunnel and the anchor under different bone density conditions remains unclear.OBJECTIVE:To explore the stress distribution of the bone tunnel and the anchor when the insertion depth of the anchor varies under different bone density conditions by using three-dimensional finite element analysis technology.METHODS:The CT image data of the humerus of volunteers were collected,and the models of the humerus and the anchor were constructed by using Mimics,3-Matic,and Solidworks software.In 3-Matic,holes with distances of 0,2,4,6,and 8 mm from the surface of the humerus were respectively created at the same position of the humerus and assembled with the anchor.In Mimics,values were assigned based on the CT gray value to obtain a model with normal bone mass(T value ≥-1.0).The parameters were changed to construct models with reduced bone mass(-2.5＜T value＜-1.0)and osteoporosis(T value＜-2.5).In each model,a 70 N pulling force was applied to the anchor along the direction tangent to the inner edge of the bone tunnel.The stress distribution and magnitude of the bone tunnel and the anchor when inserted at different depths under different bone density conditions were observed.RESULTS AND CONCLUSION:(1)When the insertion depth was the same,as the bone density decreased,the maximum equivalent stress of the anchor increased,while the maximum equivalent stress of the bone tunnel decreased.(2)When the bone density was the same,as the insertion depth of the anchor increased,the maximum equivalent stress of the anchor decreased.When the insertion depth was 4 mm,the stress of the bone tunnel was the smallest and the distribution was relatively uniform.The stress of the anchor was mainly distributed around the lower anchor hole and the proximal thread,and the stress of the bone tunnel was mainly at the part in contact with the proximal thread.The increase in the insertion depth would change the uniformity and pattern of the stress distribution,while the bone density had a relatively small impact on the stress distribution pattern.(3)It is concluded that the bone density of the humerus is crucial for the anchor repair of rotator cuff tears.It is recommended that clinicians measure the bone density of the greater tuberosity of the humerus before the operation.Excessive insertion depth of the anchor does not significantly increase its stability.Clinicians can conduct personalized preoperative assessments by using the finite element analysis method in combination with the actual situation of patients to achieve the best surgical results.

BACKGROUND:The stress effect of autophagy on epithelial cells,fibroblasts and myofibroblasts is closely related to the formation process of pulmonary fibrosis.OBJECTIVE:To screen the genes related to autophagy in patients with pulmonary fibrosis,and explore their correlation with the prognosis of patients with pulmonary fibrosis,in order to provide a new target for clinical intervention in pulmonary fibrosis.METHODS:The gene expression profiling dataset downloaded from GSE70866 was used as a training set,differentially expressed genes between pulmonary fibrosis patients and normal healthy individuals was analyzed using the R language and intersected with autophagy-related genes to identify the differentially expressed genes with the most significant changes.Multiple analysis methods were used to identify key prognostic genes and construct genetic prognostic models.Patients with pulmonary fibrosis were divided into high-risk and low-risk groups according to their risk scores,and the validity of the prognostic model was verified using the Siena cohort and Leuven cohort validation sets.A cell model of pulmonary fibrosis was established by inducing HFL-1 cells(human embryonic lung fibroblasts)with transforming growth factor-β1,and an animal model of pulmonary fibrosis was established in mice by tracheal instillation of bleomycin to validate the expressions of prognostic genes.RESULTS AND CONCLUSION:(1)There were 2 650 differentially expressed genes between fibrotic tissue and normal tissue.Among them,34 genes related to autophagy showed significant expression changes.(2)Kaplan-Meier survival analysis curves for the Siena cohort and Leuven cohort validation sets showed significantly lower survival in the high-risk group than in the low-risk group.(3)Three autophagy genes related to prognosis were screened out:myelocytomatosis viral oncogene(MYC),C-C motif chemokine ligand 2(CCL2),and GABA type a receptor associated protein like 1(GABARAPL1).(4)Both in vivo and in vitro studies showed that compared with the control group,the expression levels of myelocytomatosis viral oncogene and C-C motif chemokine ligand 2 mRNA and protein were significantly higher in the lung fibrosis model group(P＜0.01,P＜0.05),while the expression levels of GABA type a receptor associated protein like 1 mRNA and protein were lower(P＜0.001).To conclude,bioinformatics methods are used to analyze the expression of three autophagy-related genes in pulmonary fibrosis and their correlation with the prognosis of patients with pulmonary fibrosis.The constructed prognostic model has good predictive ability for the 1-,2-,and 3-year survival rates of patients with pulmonary fibrosis.Moreover,in vivo and in vitro models have been used to verify that myelocytomatosis viral oncogene and C-C motif chemokine ligand 2 are highly expressed in lung fibroblasts and tissues,and that GABA type a receptor associated protein like 1 is lowly expressed.

BACKGROUND:Obesity is not only related to metabolic diseases such as diabetes and cardiovascular disease,but also closely related to the increased risk of cognitive decline,dementia and other neurodegenerative diseases.Studies have found that aerobic exercise and resistance exercise can help improve obesity-related cognitive impairment,but their therapeutic effects and related mechanisms of action are still unclear.OBJECTIVE:To explore the protective effects of aerobic and resistance exercises on the nervous center of obesity-related cognitive impairment mice.METHODS:Forty-eight 8-week-old C57BL/6J wild-type male mice were randomly divided into four groups:a control group was fed normally for 20 weeks;a high fat group was fed with high fat diet(60％fat energy)for 20 weeks;an aerobic exercise group was fed with 12 weeks of high-fat diet followed by 8 weeks of aerobic exercise;and a resistance exercise group was fed with 12 weeks of high-fat diet followed by 8 weeks of resistance exercise.After the exercise intervention,body mass was weighed,insulin tolerance and glucose tolerance were tested to evaluate insulin resistance,and cognitive function of mice in each group was detected by new object recognition experiment and Y-maze experiment.The morphology of hippocampal and cortical tissue cells was observed by hematoxylin-eosin staining.The mRNA relative expression levels of tumor necrosis factor-α and interleukin-6 were detected by real-time fluorescence quantitative PCR,and the protein expressions of Bax,Bcl-2,nuclear factor-κB,Cleaved Caspase-1,Caspase-3,synapsin 1 and brain-derived neurotrophic factor were detected by western blot.RESULTS AND CONCLUSION:(1)Compared with the control group,the body mass of mice increased in the high-fat group(P＜0.05),accompanied by insulin resistance and cognitive dysfunction,the expression levels of nuclear factor-κB,Bax,Caspase-3,Cleaved Caspase-1 in the hippocampus were significantly increased(P＜0.05),the expression levels of brain-derived neurotrophic factor,synapsin 1and Bcl-2 proteins were significantly decreased(P＜0.05),Bcl-2/Bax ratio was significantly decreased(P＜0.05),and the mRNA levels of inflammatory cytokines,tumor necrosis factor-α and interleukin-6,were significantly up-regulated(P＜0.05).(2)Compared with the high-fat group,the above indexes were significantly improved in the aerobic exercise group(P＜0.05),while in the resistance exercise group,the body mass of mice was significantly decreased,the levels of inflammatory cytokines tumor necrosis factor-α and interleukin-6 mRNA were significantly decreased(P＜0.05),the protein expression of Caspase-3 was significantly decreased(P＜0.05),and the protein expression of brain-derived neurotrophic factor was significantly up-regulated(P＜0.05),but no significant changes were observed in the other indexes(P＞0.05).In conclusion,long-term exercise can reduce insulin resistance,down-regulate the expression of nuclear factor-κB pathway,weaken inflammatory response,inhibit neuronal apoptosis and improve synaptic plasticity,resulting in neuroprotective effects,and effectively alleviate obesity-related cognitive dysfunction in obese mice.The therapeutic effect of aerobic exercise is superior to that of resistance exercise.

BACKGROUND:Peripheral nerve axon rupture seriously affects patients' physical function and mental health.Microsurgery,nerve autograft,nerve allograft,fibrin glue and catheter technology are the main treatments for peripheral nerve injury,each of which has its own advantages and disadvantages,but the overall treatment effect is not satisfactory.Despite the clinical success of Schwann cells in promoting axonal regeneration,there are still many challenges in the treatment with Schwann cells,such as slow expansion of Schwann cells,immune rejection,and low survival rate of transplanted cells.OBJECTIVE:To summarize the role and mechanism of Schwann cells in promoting the regeneration of peripheral nerve axons,and the difficulties and challenges of Schwann cells in the process of nerve regeneration treatment.METHODS:PubMed,Medline,WanFang,VIP,and CNKI were searched by computer using the search terms of"Schwann cells,synaptic Schwann cell,macrophage,peripheral nerve axon rupture,Wallerian degeneration,Peripheral nerve axon regeneration,Central nervous system repair"in English and Chinese.Literature related to Schwann cell proliferation and differentiation,promotion of peripheral nerve regeneration,and clinical applications was retrieved from database inception to October 2024,and a total of 95 articles were finally included for review.RESULTS AND CONCLUSION:Schwann cells interact with macrophages,T cells and other cells,to initiate the regeneration process through signaling pathways,including Krox20/C-Jun,NRG-1/ErbB,Notch,MAPK,and PI3K/Akt/mTOR,synthesize and release nerve growth factors,and thus promote regeneration of the peripheral nervous system.Schwann cells have been experimentally demonstrated to have great potential in peripheral nerve repair and are expected to become the key target of therapeutic intervention.However,there are still problems such as difficulties in cell harvest and culture,as well as the occurrence of other diseases during the treatment process.

BACKGROUND:Developing a material that promotes alveolar bone regeneration and has good properties is of great significance for the treatment of alveolar bone defects.OBJECTIVE:To summarize the research on alveolar bone defect regeneration and repair in the past 5 years,classify and introduce new materials and drugs,so as to grasp the latest progress in related fields.METHODS:"Alveolar bone,alveolar bone defect,alveolar bone regeneration,mechanism,biomaterials,nanoscaffolds,hydrogels,medications,anti-inflammatory drugs,simvastatin,metformin,traditional Chinese medicine,growth factor,stem cell"were used as search terms in Chinese and English for literature retrieval in CNKI and PubMed,respectively.A total of 117 articles were finally obtained for review and analysis.RESULTS AND CONCLUSION:The application of biomaterials provides a scaffold structure for alveolar bone regeneration and can also be used as a bone substitute to repair bone defects.Topical and systemic applications of Western and Chinese medicines can control inflammation and promote bone regeneration.Materials loaded with various growth factors have the effect of osteogenesis and can promote the repair of alveolar bone defects.In stem cell tissue engineering,the seed cells are osteogenic and fibrogenic,which can differentiate into osteoblasts to generate new bone.In recent years,research has been keen on the combination of the above to develop new,biocompatible,and slow-release drugs or materials to promote the regeneration and repair of alveolar bone defects.

BACKGROUND:Previous studies have demonstrated that the cannabinoid type Ⅰ receptor can enhance the proliferation and neural differentiation of neural stem cells and mesenchymal stem cells.Moreover,cannabinoid type Ⅰ also governs the proliferation and mineralization capacity of human apical papilla stem cells.However,there are relatively few investigations concerning the impact of cannabinoid type Ⅰ overexpression on the neural differentiation of human apical papilla stem cells.OBJECTIVE:To investigate the effect of cannabinoid type Ⅰ on neural differentiation of human apical papilla stem cells in vitro.METHODS:Healthy third molars with immature root tips that need to be removed for orthodontic treatment were collected,and human apical papilla stem cells were isolated and cultured by tissue block method combined with enzyme digestion method.Cannabinoid type Ⅰ gene was introduced into human apical papilla stem cells by lentivirus-mediated transfection technique.A blank control group,a negative control group,and cannabinoid type Ⅰ overexpression group were set up.The transfection effect of overexpression of cannabinoid type Ⅰ lentivirus on human apical papilla stem cells was verified by Western Blot.The control group,negative control group,cannabinoid type Ⅰ overexpression group and cannabinoid type Ⅰ overexpression+AM251(cannabinoid type Ⅰ receptor antagonist)group were set up.Cell proliferation was detected by CCK-8 assay at 1,5,and 10 days after neural induction.On day 10 of neural induction,the expression levels of TH,NeuroD-1,and NCAM1 genes were detected by qRT-PCR,and the protein expression levels of Nestin and TUBB3 were detected by immunofluorescence.RESULTS AND CONCLUSION:(1)Compared with the blank control group and the negative control group,the expression of cannabinoid receptor Ⅰ protein in the cannabinoid receptor Ⅰ overexpression group was significantly increased,and the difference was significant(P＜0.05).(2)Compared with the blank control group and the negative control group,the proliferation ability of human apical papilla stem cells in the cannabinoid type Ⅰ overexpression group was the strongest at 5 and 10 days after neural induction(P＜0.05).(3)Compared with the blank control group and the negative control group,the mRNA expression of NeuroD-1,NCAM1,and TH in the stem cells of the human apical papilla in the cannabinoid type Ⅰ overexpression group was significantly increased,and the fluorescence intensity of Nestin and TUBB3 was significantly enhanced(P＜0.05).(4)Compared with the cannabinoid type Ⅰ overexpression group,the proliferation ability,mRNA expression level of NeuroD-1,NCAM1,and TH,as well as the fluorescence intensity of Nestin and TUBB3,were significantly decreased in the cannabinoid type Ⅰ overexpression+AM251 group(P＜0.05).These findings conclude that overexpression of cannabinoid type Ⅰ promoted the proliferation and neural differentiation of human apical dentin papilla stem cells.

BACKGROUND:Lysosomal storage diseases,as a group of rare genetic metabolic disorders,exhibit complex pathogenesis often leading to dysfunction of cells,tissues,and organs.Current therapeutic approaches have certain limitations.Stem cell transplantation,as an emerging treatment method,offers new options for patients with lysosomal storage diseases.OBJECTIVE:To review the mechanisms of action of stem cells in regulating lysosomes for the treatment of lysosomal storage diseases and explore the feasibility of traditional Chinese medicine in treating such diseases,providing new insights for the treatment of lysosomal storage diseases with stem cells.METHODS:Relevant literature from 2010 to 2024 was searched in CNKI and PubMed databases using keywords"stem cells,lysosomal storage disease,lysosome"in English and Chinese.Ultimately,78 articles were included for review and analysis.RESULTS AND CONCLUSION:(1)Stem cells treat lysosomal storage diseases by regulating lysosomes primarily through three aspects:regulating stem cell differentiation and replacement,improving intercellular communication and the microenvironment,and enhancing lysosomal enzyme expression through gene editing.(2)Stem cells have achieved significant effects in the treatment of some lysosomal storage diseases,such as Niemann-Pick disease,mucopolysaccharidoses,Gaucher disease,and metachromatic leukodystrophy.(3)The procedure for stem cell transplantation needs further optimization.Adverse reactions post-transplantation urgently need to be addressed,and the efficiency and safety of gene-modified stem cells also need to be further improved.In the future,more research on the treatment of lysosomal storage diseases with traditional Chinese medicine is required to reveal the relevant mechanisms for the treatment of lysosomal storage diseases with traditional Chinese medicine.

BACKGROUND:Exosomes derived from mesenchymal stem cells play pivotal roles in cell communication and epigenetic regulation due to their low immunogenicity and targeted delivery effects,and have been clinically applied in the treatment of various diseases.OBJECTIVE:To review the isolation,purification,identification methods,and application progress of mesenchymal stem cell-derived exosomes,and to facilitate the development of large-scale preparation techniques and clinical translation of mesenchymal stem cell-derived exosomes.METHODS:The Chinese search terms"exosome,mesenchymal stem cells,isolation,purification,characterization,clinical application"and the English search terms"exosome,extracellular vesicles,mesenchymal stem cells,isolation,characterization,application"were used to search the literature published before September 2024 in CNKI,PubMed,and Web of Science databases.Articles with poor relevance to the topic,outdated,or duplicated content were excluded,and finally,109 articles were included for review.RESULTS AND CONCLUSION:(1)This paper reviews recent methods for isolating and purifying exosomes,comparing the characteristics of ultracentrifugation,ultrafiltration,size-exclusion chromatography,polymer precipitation,immunoaffinity,microfluidic methods,and other novel approaches based on their underlying principles.(2)Methods for identifying exosomes can be categorized into physical and biochemical analyses,characterizing exosomes based on their shape,size,and characteristic proteins.(3)Mesenchymal stem cell-derived exosomes have broad applications in multiple fields such as medical aesthetics,wound repair,and cancer treatment,due to their immune-regulatory properties and ability to cross biological barriers.(4)The clinical translation of exosomes faces challenges due to their complex structure,lack of universal isolation techniques,and poor stability,making it difficult to achieve in a short period of time.

BACKGROUND:One of the advantages of clear aligner treatment is molar distalization.However,tooth tilting movement and loss of anterior anchorage may occur during treatment.There are few studies on whether these problems can be improved by selecting clear aligners with different thicknesses and edges to improve the clinical treatment effect.OBJECTIVE:To analyze the control ability of clear aligners with different thickness and edges on the central incisor,lateral incisor,and second molar when pushing the maxillary second molar distally by three-dimensional finite element analysis.METHODS:Three-dimensional finite element analysis models of bilateral maxillary second molar distalization with clear aligner,maxillary dentition,periodontal ligament,and alveolar bone with different thicknesses and margins were established by Mimics,Geomagic Wrap,3-matic and SolidWorks software,respectively.There were 16 combinations of four thicknesses(0.4,0.5,0.625,and 0.75 mm)and four margins(scallop,straight,straight extension 2 mm and straight extension 4 mm).The data were imported into Ansys Workbench software for design and solution.The mean value,peak value and distribution of the periodontal ligament equivalent stress of the second molar,the equivalent stress and the maximum initial displacement of the second molar,and the control ability of each appliance on the second molar,central incisor,and lateral incisor were analyzed.RESULTS AND CONCLUSION:(1)The mean equivalent stress of periodontal ligament of the second molar,the equivalent stress of the second molar and the maximum initial displacement of the second molar increased with the extension of the appliance edge and the increase of the thickness of the appliance in the 16 groups of models.(2)When the thickness of appliances was the same,the maximum equivalent stress of the second molar in the linear appliance group was the highest,and the maximum equivalent stress of the second molar in the linear extended appliance group was greater than that in the scallop appliance group.When the edge of the appliance was the same,the periodontal ligament equivalent stress peak of the second molar increased with the increase of the thickness of the appliance.The equivalent stress distribution in the periodontal ligament of the second molar in the linear extendable appliance group was more uniform than that in the scallop appliance group and the linear appliance group.(3)When the thickness of the appliance was the same,the scallop-shaped appliance had the worst control on the second molar.When the edge of the appliance was the same,with the increase of the thickness of the appliance,the control of the second molar by the linear extender appliance was gradually stronger than that by the linear appliance.The control of the central incisor was stronger and more stable with the linear extended 2 mm appliance,while the control of the lateral incisor was stronger and more stable with the linear appliance.(4)The results showed that when using clear aligners to push molars distally,extending the edge of the appliance could improve the control of the molars and reduce the tilting movement of the teeth.The design of a straight extension margin of 2 mm for the central incisor and a straight edge for the lateral incisor can enhance the control of the anchorage incisor and reduce the labial inclination of the anterior teeth.

BACKGROUND:Mesenchymal stem cells show extremely therapeutic potential for radiation-induced lung injury through delivering exosomes.Age is a primary factor affecting the function and biological efficacy of mesenchymal stem cells.OBJECTIVE:To investigate the protective effects of exosomes derived from bone marrow mesenchymal stem cells of different mouse ages on radiation-induced lung injury in mice.METHODS:Bone marrow mesenchymal stem cells of young mice and old mice were obtained by whole bone marrow adherent culture.The exosomes were isolated from the supernatant of passage 3 bone marrow mesenchymal stem cells.Ten 2-month-old C57BL/6J mice were randomly selected as the control group after anesthesia and not irradiated.The remaining 30 2-month-old C57BL/6J mice were used to establish a mouse radiation-induced lung injury model and were randomly divided into three groups.Exosomes derived from bone marrow mesenchymal stem cells of young mice,exosomes derived from bone marrow mesenchymal stem cells of old mice,and PBS were injected through the tail vein,respectively.The survival rate of mice was monitored.The lung function,lung inflammation and fibrosis were assessed at 1 and 12 weeks after irradiation.RESULTS AND CONCLUSION:(1)The concentrations of particles and proteins in exosomes derived from bone marrow mesenchymal stem cells of young mice were higher than those in exosomes derived from bone marrow mesenchymal stem cells of old mice.(2)Compared with the control group,the survival rate of mice in the PBS group was low,and lung inflammation was obvious at week 1 after irradiation,and the levels and mRNA expressions of interleukin-1β,interleukin-6,and tumor necrosis factor-α were increased.Collagen deposition in lung tissues was observed at week 12 after irradiation,and the mRNA level of E-cadherin was decreased,while the mRNA levels of α-smooth muscle actin,transforming growth factor-β1,and β-catenin were increased.(3)Compared with the PBS group,the survival rate of mice in the exosome group was significantly improved,and the level of proinflammatory factors and their mRNA expression were reduced at week 1 after irradiation,the mRNA level of E-cadherin was increased,and the mRNA levels of α-smooth muscle actin,transforming growth factor β1 and β-catenin were reduced at week 12 after irradiation.(4)Among all the above indicators,the therapeutic effect of exosomes derived from bone marrow mesenchymal stem cells of young mice was better than that of exosomes derived from bone marrow mesenchymal stem cells of old mice.(5)The results showed that exosomes derived from bone marrow mesenchymal stem cells of young mice contained more particles and proteins,and the effect of alleviating early inflammation and late fibrosis of radiation-induced lung injury in mice was better than that of exosomes derived from bone marrow mesenchymal stem cells of old mice.