BACKGROUND:Bone relies on the close connection between blood vessels and bone cells to maintain its integrity.Bones are in a physiologically hypoxic environment.Therefore,the study of angiogenesis and osteogenesis in hypoxic environment is closer to the microenvironment in vivo. OBJECTIVE:To explore the influence of Wenshen Tongluo Zhitong(WSTLZT)formula on H-type bone microvascular endothelial cell/bone marrow mesenchymal stem cell co-culture system in hypoxia environment and its related mechanism. METHODS:Enzyme digestion method and flow sorting technique were used to isolate and identify H-type bone microvascular endothelial cells.Mouse bone marrow mesenchymal stem cells were isolated and obtained by bone marrow adhesion method.H-type bone microvascular endothelial cell/bone marrow mesenchymal stem cell hypoxic co-culture system was established using Transwell chamber and anoxic culture workstation.WSTLZT formula powder was used to intervene in each group at a mass concentration of 50 and 100 μg/mL.The angiogenic function of H-type bone microvascular endothelial cells in the co-culture system was evaluated by scratch migration test and tube formation test.The osteogenic differentiation ability of bone marrow mesenchymal stem cells in the co-cultured system was evaluated by alkaline phosphatase staining and alizarin red staining.The protein and mRNA expression changes of PDGF/PI3K/AKT signal axis related molecules in H-type bone microvascular endothelial cells in the co-cultured system were detected by Western Blotting and q-PCR,respectively. RESULTS AND CONCLUSION:(1)Compared with the normal oxygen group,the scratch mobility and new blood vessel length of H-type bone microvascular endothelial cells were significantly higher(P<0.05);the osteogenic differentiation capacity of bone marrow mesenchymal stem cells was higher(P<0.05);the expression of PDGF/PI3K/AKT axis-related molecular protein and mRNA increased(P<0.05)in the hypoxia group.(2)Compared with the hypoxia group,scratch mobility and new blood vessel length were significantly increased in the H-type bone microvascular endothelial cells(P<0.05);bone marrow mesenchymal stem cells had stronger osteogenic function(P<0.05);the expression of PDGF/PI3K/AKT axis-related molecular proteins and mRNA further increased(P<0.05)after treatment with different dose concentrations of WSTLZT formula.These findings conclude that H-type angiogenesis and osteogenesis under hypoxia may be related to the PDGF/PI3K/AKT signaling axis,and WSTLZT formula may promote H-type vasculo-dependent bone formation by activating the PDGF/PI3K/AKT signaling axis,thereby preventing and treating osteoporosis.

BACKGROUND:Apoptosis plays an important role in secondary brain injury.Therefore,to explore the pathophysiological mechanism of promoting nerve cell survival after traumatic brain injury provides a new direction and theoretical basis for the prevention and treatment of traumatic brain injury. OBJECTIVE:To explore the expression changes of Lnx1 molecule in mammalian cortical neurons after brain injury and the possible mechanism involved in secondary brain injury. METHODS:Eighty adult SD rats were divided into 20 male and 20 female mice in sham operation group and 20 male and 20 female mice in traumatic brain injury group.The traumatic brain injury rat model was established by heavy falling method.At 6,12,24,48,and 72 hours after brain injury,the expression of related molecules in damaged cortical neurons was analyzed by RT-qPCR,western blot assay,and immunofluorescence staining. RESULTS AND CONCLUSION:(1)The brain tissue of traumatic brain injury group was bleeding and obvious tissue injury could be observed.Water content of brain tissue increased after traumatic brain injury.(2)Compared with the sham operation group,the expression of Lnx1 in cortical neurons after traumatic brain injury increased significantly at 24 hours after injury.(3)After traumatic brain injury,the expression of PBK and BCR protein decreased,and the pro-survival factor ctgf increased.(4)These findings suggest that after traumatic brain injury,the expression of Lnx1 is up-regulated in neurons,which may be due to the decrease of the expression of its target molecules PBK and BCR,and further promote the expression of living factor ctgf,which has a protective effect on the damaged neurons.

BACKGROUND:Radiotherapy for head and neck tumors is very likely to cause radiation-induced oral mucositis,which seriously affects the health of patients and the treatment plan of tumors.Mesenchymal stem cells have shown therapeutic potential in many diseases,and exosomes are one of the important factors for their function.At present,there is no application of adipose mesenchymal stem cell-derived exosomes in the study of radiation-induced oral mucositis. OBJECTIVE:To investigate the role of adipose mesenchymal stem cell-derived exosomes in radiation-induced oral mucositis. METHODS:Adipose mesenchymal stem cells and adipose mesenchymal stem cell-derived exosomes were extracted and identified.In vitro model of radiation-induced oral mucositis was induced by radiating oral mucosal epithelial cells with 3 Gy X-ray.Adipose mesenchymal stem cells or adipose mesenchymal stem cell-derived exosomes were pretreated for 48 hours before modeling.The proliferation capacity of oral mucosal epithelial cells was detected by EdU assay and clonal formation assay.A mouse model of radiation-induced oral mucositis was constructed through 3 Gy X-ray radiation.Adipose mesenchymal stem cells and adipose mesenchymal stem cell-derived exosomes were injected into the tail vein of radiation-induced oral mucositis mice.Hematoxylin-eosin staining and immunohistochemistry were used to evaluate the inflammatory changes of oral mucosal epithelial tissue. RESULTS AND CONCLUSION:(1)Compared with the control group,both adipose mesenchymal stem cells and adipose mesenchymal stem cell-derived exosomes promoted the formation of oral epithelial cell clones and increased the positive rate of EdU in oral epithelial cells.(2)Both adipose mesenchymal stem cells and adipose mesenchymal stem cell-derived exosomes alleviated the inflammation of oral mucosal epithelium of irradiated mice;CD45 positive cells decreased and PCNA positive cells increased in oral mucosal epithelium.It is concluded that adipose mesenchymal stem cell-derived exosomes promote the proliferation of oral mucosal epithelial cells and release oral mucosal inflammation in mice with radiation-induced oral mucositis.

BACKGROUND:Inflammation affects the osteogenic differentiation of periodontal ligament stem cells,and the osteogenic ability and autophagy level of periodontal ligament stem cells are closely related.However,there are no relevant reports on whether inflammation affects the osteogenic ability and autophagy level of periodontal ligament stem cells at different stages of osteogenic differentiation. OBJECTIVE:To explore alkaline phosphatase expression and autophagy periodontal ligament stem cells levels in periodontitis and normal conditions. METHODS:Periodontal ligament stem cells from normal and periodontitis patients were isolated and cultured,and underwent Vimentin,pan-CK,and Stro-1 fluorescence staining.At 3,7,and 14 days of osteogenic differentiation,western blot assay was used to detect the protein expression levels of alkaline phosphatase,LC3B,Beclin1,and ATG5 in normal and inflammatory periodontal ligament stem cells.The mRNA expression levels of alkaline phosphatase,bone sialoprotein,osteocalcin,Runx2,LC3B,Beclin1,and ATG5 were detected by real-time PCR. RESULTS AND CONCLUSION:(1)Stro-1 was positive,Vimentin was positive,and pan CK was negative in periodontal ligament stem cells.(2)At 3,7,and 14 days after osteogenic differentiation,compared with normal periodontal ligament stem cells,the mineralization nodules formed by periodontal ligament stem cells from inflammatory sources were significantly reduced(P<0.01);the expression of alkaline phosphatase protein and mRNA was significantly lower(P<0.05);the mRNA expression levels of bone sialoprotein,osteocalcin,and Runx2 were significantly decreased(P<0.05).(3)At 7 and 14 days after osteogenic differentiation,compared with normal periodontal ligament stem cells,the expression levels of ATG5,LC3B,and Beclin1 proteins and mRNA of periodontal ligament stem cells were downregulated(P<0.05).These findings suggest that inflammation reduces the activity of periodontal ligament stem cells in mineralizing nodule formation and the expression of alkaline phosphatase and weakens the autophagy potential of periodontal ligament stem cells at 7 and 14 days after osteogenic differentiation.

BACKGROUND:Differentially expressed RNA-binding proteins in the intervertebral disc plays a key role in intervertebral disc degeneration,and decreased levels of the RNA-binding protein KRT18 are associated with degenerative disc disease,but its specific role in the nucleus pulposus cells has not yet been fully determined. OBJECTIVE:To investigate the interaction of KRT18 with mRNA and long non-coding RNA on nucleus pulposus cells of the intervertebral disc and its mechanism. METHODS:Normal and degenerated nucleus pulposus cells were obtained from nucleus pulposus samples of patients undergoing interbody fusion for lumbar fracture or intervertebral disc degeneration.iRIP-seq,functional enrichment analysis,and DNA microarray analysis were performed to identify the mRNA and long non-coding RNA binding with KRT18.Subsequently,KRT18 was knocked down in nucleus pulposus cells based on the analysis results,and the expression levels of related genes were detected at the protein and RNA levels through protein immunoblotting and qRT-PCR,respectively. RESULTS AND CONCLUSION:Through iRIP-seq analysis,we identified abundant KRT18 binding sites within the GUAAUC and AGCCUC sequences,indicating that KRT18 may be involved in regulating RNA transcription,translation,stability or play a role in cell signaling pathways.It can stably bind to mature mRNA,among which highly expressed genes include CRLF1,IGFBP4,etc.At the same time,the peak genes of long non-coding RNA binding with it include SNHG25,SNHG12,NEAT1,USP32,EIF4A2 and CDH4.Most of these genes are involved in various biological processes such as apoptosis and inflammation,and can mediate related pathways of extracellular matrix metabolism.KRT18 can regulate their stability,transport,translation,splicing and other functions,thus affecting gene expression and cell function.We further verified through experiments the knockdown of KRT18 in nucleus pulposus cells,and found that the level of extracellular matrix metabolism was inhibited and unbalanced,resulting in intervertebral disc degeneration in vitro.This study investigated the regulatory mechanism of KRT18 from the perspective of its binding with mRNA and long non-coding RNA for the first time,and speculated the potential function of KRT18 in the pathogenesis of intervertebral disc degeneration,laying a foundation for future research on the key functions of KRT18.

BACKGROUND:Muscle aging is closely related to various epigenetic changes,and exercise has a certain regulatory effect on these epigenetic changes.However,the specific mechanism is not fully understood. OBJECTIVE:To review the epigenetic mechanisms of skeletal muscle and how exercise can improve skeletal muscle aging and promote adaptive changes in muscle through these epigenetic mechanisms,aiming to provide a more comprehensive understanding of skeletal muscle aging and disease mechanisms. METHODS:During the period from June 1st to August 1st,2023,literature searches were conducted for relevant literature published from database inception to August 2023 in databases including Web of Science,PubMed,CNKI,WanFang,and VIP.The search terms used included"skeletal muscle,""muscle,""aging,""older adult,""aging,""exercise,""physical exercise,""epigenetic,"and"epigenetics"in Chinese as well as"skeletal muscle,muscle,aging,older adult,senescence,age,exercise,sports,physical activity,epigenetic,epigenetics"in English.Boolean logic operators were used to connect the search terms for retrieval,and corresponding strategies were developed.According to the predetermined inclusion and exclusion criteria,70 eligible articles were selected. RESULTS AND CONCLUSION:Epigenetics refers to the phenomenon where gene expression and function are regulated without changes in gene sequence,and epigenetic changes in skeletal muscle are an important field.The epigenetic mechanisms of skeletal muscle play an important role in muscle aging,mainly involving DNA methylation,histone modification,regulation of non-coding RNAs,chromatin remodeling,changes in mitochondrial function and expression changes of aging-related genes.Exercise significantly regulates the epigenetics of skeletal muscle,including promoting DNA methylation,muscle histone modification,regulating miRNA expression,and regulating lncRNA expression,regulating muscle factors(such as interleukin-6),regulating mitochondrial function(such as peroxisome proliferators-activated receptors γ co-activator 1α).Future studies are recommended for long-term,cross-diverse population-based exercise interventions;the application of multi-omics techniques such as proteomics and metabolomics;strengthening the understanding of epigenetic changes at the single-cell level;cross-species comparative studies as well as human clinical trials for the translation of animal model findings to humans;strategies for combining exercise and pharmacological interventions to assess their synergistic effects;and epigenetic studies of crosstalk interactions between skeletal muscle and different organs.

BACKGROUND:There is still no consensus on the optimal internal fixation for the treatment of Pauwels Ⅲ femoral neck fracture,and most of the related finite element analyses have been performed using a single simplified loading condition,and the biomechanical properties of commonly used internal fixation devices need to be further investigated. OBJECTIVE:To analyze the biomechanical characteristics of Pauwels Ⅲ femoral neck fractures treated with cannulated compression screw,dynamic hip screw,and femoral neck system by finite element method under different loading conditions of single-leg standing loads and sideways fall loads. METHODS:The DICOM data of healthy adult femur were obtained by CT scanning,imported into Mimics 15.0 software to obtain the rough model of bone tissue.The data exported from Mimics were optimized by Geomagics software,and then three internal fixation models were built and assembled with the femur model according to the parameters of the clinical application of the cannulated compression screw,dynamic hip screw,and femoral neck system by using Pro/E software.Finally,the three internal fixation models were imported into Ansys software for loading and calculation to analyze the stress distribution and displacement of the femur and the internal fixation under different working conditions of single-leg standing loads and sideways fall loads,as well as the stress characteristics of the calcar femorale and Ward's triangle. RESULTS AND CONCLUSION:(1)Under the single-leg standing load and the sideways fall load,the proximal femoral stress of the three internal fixation models was mainly distributed above the fracture end of the femoral neck.The peak stress of the proximal femoral end,fracture end,Ward triangle,and calcar femorale of the three internal fixation models were the smallest in the femoral neck system model and the largest in the cannulated compression screw model.(2)Under the single-leg standing load and the sideways fall load,the peak displacement of the proximal femur of the three internal fixation models was all located at the top of the femoral head,and the peak displacement was the smallest in the femoral neck system model and the largest in the cannulated compression screw model.(3)The peak displacement of the three internal fixation models was all located at the top of the internal fixation device under the single-leg standing and sideways fall loading conditions,and the peak displacement values were the smallest in the femoral neck system internal fixation model and the largest in the cannulated compression screw internal fixation model.(4)The internal fixation stress of the three internal fixation models was mainly distributed in the area near the fracture end of the internal fixation device under the single-leg standing and sideways fall loads,and the peak value of internal fixation stress was the smallest in the femoral neck system model and the largest in the cannulated compression screw model.(5)These results suggest that the mechanical stability of the femoral neck system is the best,but there may be a risk of stress shielding of the fracture end and calcar femorale.The stress of the internal fixation device of the femoral neck system is more dispersed,and the risk of internal fixation break is lower.

BACKGROUND:It has also been confirmed that ferroptosis is closely related to a variety of musculoskeletal diseases,such as rheumatoid arthritis,osteosarcoma,and osteoporosis.The pathophysiological mechanisms of ferroptosis and osteoporosis need to be further studied and elucidated to broaden our understanding of iron metabolism and osteoporosis.It will provide research ideas for the future elucidation of new mechanisms of osteoporosis and the development of new technologies and drugs for the treatment of osteoporosis. OBJECTIVE:To provide an overview of the current status of research on ferroptosis in osteoporosis,to provide a new direction for future research on the specific molecular mechanisms of osteoporosis,and to provide more effective and better options for osteoporosis treatment strategies. METHODS:The first author used the computer to search the literature published from 2000 to 2024 in CNKI,WanFang,VIP,and PubMed databases with search terms"ferroptosis,iron metabolism,osteoporosis,osteoblast,osteoclast,bone metabolism,signal pathway,musculoskeletal,review"in Chinese and English.A total of 68 articles were finally included according to the selection criteria. RESULTS AND CONCLUSION:(1)Ferroptosis is a new type of cell death discovered in recent years,which is usually accompanied by a large amount of iron accumulation and lipid peroxidation during cell death,and its occurrence is iron-dependent.This is distinctly different from several types of cell death that are currently being hotly studied(e.g.,cellular pyroptosis,necrotic apoptosis,cuproptosis,and autophagy).(2)Intracellular iron homeostasis is manifested as a balance between iron uptake,export,utilization,and storage.The body's iron regulatory system includes systemic and intracellular regulation.The main factor of systemic regulation is hepcidin produced by hepatic secretion,and cellular regulation depends on the iron regulatory protein/iron response element system.Of course,intracellular iron homeostasis can be controlled by other factors,such as hypoxia,cytokines,and hormones.(3)Lipid peroxidation causes oxidative damage to biological membranes(plasma membrane and internal organelle membranes),lipoproteins,and other lipid-containing molecules.Polyunsaturated fatty acid-containing phospholipids are important targets of lipid peroxidation.Free polyunsaturated fatty acid is an important substrate for lipid oxidation and can bind to the phospholipid bilayer,leading to over-oxidation and thus triggering lipid apoptosis.(4)Several studies have shown that osteoblasts are overloaded with iron in different ways,resulting in the accumulation of unstable ferrous iron and the generation of reactive oxygen species and lipid peroxides,causing ferroptosis of osteoblasts and ultimately a decrease in bone formation,affecting bone homeostasis and the development of osteoporosis.(5)Osteoclasts are large multinucleated cells formed by the fusion of mononuclear macrophage cell lines or bone marrow mesenchymal stem cells induced by nuclear factor-κB ligand receptor activator,and they have the function of bone resorption.Iron ions can promote osteoclast differentiation and bone resorption through the production of intracellular lipid reactive oxygen species,while iron chelators can inhibit osteoclast formation in vitro and thus affect the occurrence and development of osteoporosis.

OBJECTIVE:Anterior cervical decompression and fusion is a classic surgical method for the treatment of degenerative cervical spondylosis.The use of nail plates increases the fusion rate and stability and indirectly leads to adjacent vertebral degeneration and postoperative dysphagia.In this paper,the clinical results and complications of ROI-CTM self-locking system and traditional cage combined with screw-plate internal fixation in the treatment of degenerative cervical spondylosis were compared by meta-analysis to provide evidence-based support for the selection of internal fixation methods in anterior cervical decompression and fusion. METHODS:CNKI,WanFang,VIP,PubMed,Cochrane Library,Web of Science,and Embase databases were searched for Chinese and English literature on the application of ROI-CTM self-locking system and fusion cage combined with screw plate internal fixation in the treatment of degenerative cervical spondylosis.The retrieval time range was from inception to July 2023.Two researchers selected the literature strictly according to the inclusion and exclusion criteria.The Cochrane bias risk tool was used to evaluate the quality of randomized controlled trials.Newcastle-Ottawa Scale was used to assess the quality of cohort studies.Meta-analysis was performed using RevMan 5.4 software.Outcome indicators included operation time,intraoperative blood loss,Japanese Orthopaedic Association score,Neck Disability Index,C2-C7 Cobb angle,fusion rate,incidence of adjacent vertebral degeneration,cage subsidence rate,and incidence of dysphagia. RESULTS:Thirteen articles were included,including eleven retrospective cohort studies and two randomized controlled trials,with 1 136 patients,569 in the ROI-C group,and 567 in the cage combined with the nail plate group.Meta-analysis results showed that the operation time(MD=-15.52,95%CI:-18.62 to-12.42,P<0.000 01)and intraoperative blood loss(MD=-24.53,95%CI:-32.46 to-16.61,P<0.000 01)in the ROI-C group and the fusion device combined with nail plate group.Postoperative adjacent segment degeneration rate(RR=0.40,95%CI:0.27-0.60,P<0.000 01)and postoperative total dysphagia rate(RR=0.18,95%CI:0.13-0.26),P<0.000 01)were statistically different.The two groups had no significant difference in Japanese Orthopaedic Association score,Neck Disability Index,C2-C7 Cobb angle,fusion rate,or cage subsidence rate(P≥0.05). CONCLUSION:Applying an ROI-CTM self-locking system and traditional cage combined with plate internal fixation in anterior cervical decompression and fusion can achieve satisfactory clinical results in treating degenerative cervical spondylosis.The operation of the ROI-CTM self-locking system is more straightforward.Compared with a cage combined with plate internal fixation,the ROI-CTM self-locking system can significantly reduce the operation time and intraoperative blood loss and has obvious advantages in reducing the incidence of postoperative dysphagia and adjacent segment degeneration.The ROI-CTM self-locking system is recommended for patients with skip cervical spondylosis and adjacent vertebral disease.However,given its possible high settlement rate,using a fusion cage combined with screw-plate internal fixation is still recommended for patients with degenerative cervical spondylosis with multiple segments and high-risk factors of fusion cage settlement,such as osteoporosis and vertebral endplate damage.

BACKGROUND:We have successfully established an animal model of small ear pig in southern Yunnan province with internal tension relieving technique combined with autologous Achilles tendon for anterior cruciate ligament reconstruction,and verified the stability and reliability of the model.However,whether internal tension relieving technique can promote the ligamentalization process of autologous Achilles tendon graft has not been studied. OBJECTIVE:To investigate the differences in the process of ligamentalization between conventional reconstruction and internal reduction reconstruction of the anterior cruciate ligament by gross view,histology and electron microscopy. METHODS:Thirty adult female small ear pigs in southern Yunnan province were selected.Anterior cruciate ligament reconstruction was performed on the left knee joint with the ipsilateral knee Achilles tendon(n=30 in the normal group),and anterior cruciate ligament reconstruction was performed on the right knee joint with the ipsilateral knee Achilles tendon combined with the internal relaxation and enhancement system(n=30 in the relaxation group).The autogenous right forelimb was used as the control group;the anterior cruciate ligament was exposed but not severed or surgically treated.At 12,24,and 48 weeks after surgery,10 animals were sacrificed,respectively.The left and right knee joint specimens were taken for gross morphological observation to evaluate the graft morphology.MAS score was used to evaluate the excellent and good rate of the ligament at each time point.Hematoxylin-eosin staining was used to evaluate the degree of ligament graft vascularization.Collagen fibers and nuclear morphology were observed,and nuclear morphology was scored.Ultrastructural remodeling was evaluated by scanning electron microscopy and transmission electron microscopy. RESULTS AND CONCLUSION:(1)The ligament healing shape of the relaxation group was better at various time points after surgery,and the excellent and good rate of MAS score was higher(P<0.05).Moreover,the relaxation group could obtain higher ligament vascularization score(P<0.05).(2)The arrangement of collagen bundles and fiber bundles in the two groups gradually tended to be orderly,and the transverse fiber connections between collagen gradually increased and thickened,suggesting that the strength and shape degree of the grafts were gradually improved,but the ligament remodeling in the relaxation group was always faster than that in the normal group at various time points after surgery.(3)The diameter,distribution density,and arrangement degree of collagen fibers in the relaxation group were better than those in the normal group at all time points,especially in the comparison of collagen fiber diameter between and within the relaxation group(P<0.05).