BACKGROUND:Spinal canal decompression using uniportal endoscopic surgery is a new minimally invasive surgery in the treatment of lumbar spinal stenosis.However,this technique needs a steep learning curve and high requirements for surgical equipment and instruments,which limits its clinical application.We previously use the spinal endoscopy as a monitoring endoscopy and combined with unilateral biportal endoscopy to propose a hybrid technique of spinal endoscopy to achieve coaxial endoscopic operation and hands-separate operation. OBJECTIVE:To compare the clinical outcome of hybrid technique and uniportal endoscopic surgery in treatment of lumbar spinal stenosis with bilateral lower limb pain symptoms. METHODS:Ninety patients diagnosed of lumbar spinal stenosis with bilateral symptoms were included and retrospectively analyzed at First People's Hospital,Shanghai Jiao Tong University from August 2020 to August 2022.44 cases were included in group A(hybrid technique group),while 46 cases were included in group B(uniportal endoscopic surgery).The nerve decompression was observed during the surgery.Operation time,hospital stay time,and expenses were recorded in both groups.The visual analog scale scores of lower back pain and both lower extremities pain,Oswestry disability index scores of quality of life and excellent and good rate of modified Macnab criteria were recorded and compared at preoperative,postoperative 3 days,and postoperative 3 and 6 months. RESULTS AND CONCLUSION:(1)The operation time of group A was significantly shorter than that of group B(P<0.05).(2)The lower back pain and lower extremity pain of the severe side at postoperative 3 days,and 3 and 6 months were significantly relieved in both groups(P<0.05).The visual analog scale score of lower extremity pain on the mild side was significantly decreased at postoperative 3 days,3 and 6 months than preoperative score in the group A(P<0.05).The visual analog scale score of lower extremity pain on the mild side was significantly decreased at postoperative 3 days than preoperative score in the group B(P<0.05).The visual analog scale scores of lower extremity pain on the mild side at postoperative 3 and 6 months did not show significant difference than preoperative score in the group B.The comparison between the two groups showed that there was no significant difference in the visual analog scale scores of postoperative lower back pain and lower extremity pain of the severe side(P>0.05).The visual analog scale scores of lower extremity pain on the mild side in the group A were significantly lower than those of group B at postoperative 3 and 6 months(P<0.05).(3)The Oswestry disability index scores of both groups at postoperative 3 day were significantly lower than preoperative score(P<0.05),and there was no significant difference between the two groups 3 days after operation.Oswestry disability index scores of group A at postoperative 3 and 6 months were significantly decreased than preoperative score(P<0.05).The Oswestry disability index scores of group B at postoperative 3 and 6 months did not show significant differences than preoperative score(P>0.05).The comparison between the two groups showed the Oswestry disability index scores of group A were significantly lower than group B at postoperative 3 and 6 months(P<0.05).(4)The results of modified Macnab showed that the excellent and good rate of group A was significantly higher than that of group B(95%,78%,P<0.05).(5)It is indicated that the hybrid technique is a new spinal endoscopy technique,which has the advantages of less trauma and faster recovery as a minimally invasive surgery.The clinical outcome of hybrid technique is superior to that of uniportal endoscopic surgery in the treatment of lumbar spinal stenosis with bilateral symptoms.Additionally,it also has the advantages of good operational flexibility and high decompression efficiency as an open surgery.

BACKGROUND:Degenerative scoliosis is defined as a condition that occurs in adulthood with a coronal cobb angle of the spine>10° accompanied by sagittal deformity and rotational subluxation,which often produces symptoms of spinal cord and nerve compression,such as lumbar pain,lower limb pain,numbness,weakness,and neurogenic claudication.The finite element method is a mechanical analysis technique for computer modelling,which can be used for spinal mechanics research by building digital models that can realistically restore the human spine model and design modifications. OBJECTIVE:To review the application of finite element method in the etiology and treatment of degenerative scoliosis. METHODS:The literature databases CNKI,PubMed,and Web of Science were searched for articles on the application of finite element method in degenerative scoliosis published before October 2023.Search terms were"finite element analysis,biomechanics,stress analysis,degenerative scoliosis,adult spinal deformity"in Chinese and English.Fifty-four papers were finally included. RESULTS AND CONCLUSION:(1)The biomechanical findings from the degenerative scoliosis model constructed using the finite element method were identical to those from the in vivo experimental studies,which proves that the finite element method has a high practical value in degenerative scoliosis.(2)The study of the etiology and treatment of degenerative scoliosis by the finite element method is conducive to the prevention of the occurrence of the scoliosis,slowing down the progress of the scoliosis,the development of a more appropriate treatment plan,the reduction of complications,and the promotion of the patients'surgical operation.(3)The finite element method has gradually evolved from a single bony structure to the inclusion of soft tissues such as muscle ligaments,and the small sample content is increasingly unable to meet the research needs.(4)The finite element method has much room for exploration in degenerative scoliosis.

BACKGROUND:Ossification of the ligamentum flavum was previously considered to be rare in the population.As research has progressed,its incidence rate is increasing gradually,which has aroused the interest of a large number of researchers. OBJECTIVE:To visualize and analyze the research results on ossification of the ligamentum flavum from the Web of Science Core Collection since 1999 using bibliometric methods,and to review the research history of ossification of the ligamentum flavum,highlighting important literature,summarizing research hotspots,and providing ideas for researchers to find research directions. METHODS:Using the Web of Science Core Collection as the data source,relevant papers on ossification of the ligamentum flavum were searched and screened.VOSviewer 1.6.19 and CiteSpace 6.2.R6 were used to conduct the visual analysis of annual publication volume,research countries,institutions,citations,journals,authors,and keywords. RESULTS AND CONCLUSION:(1)A total of 347 papers were included.Since 1999,the number of published papers has increased in a spiral pattern.China's research started later than Japan's,but the number of publications has come up later,with Peking University being the institution with the most publications,and Prof.Chen Zhongqiang from Peking University being the scholar with the most publications.(2)Five of the 10 most frequently cited publications were related to the surgical treatment of the disease.(3)Excluding keywords directly related to the research topic and synthetically analyzing frequencies and betweenness centralities of key words,terms such as"thoracic myelopathy,""dural ossification,""minimally invasive surgery,"and"ossification of the posterior longitudinal ligament"occupied a central position in this field.(4)Keywords clustering analysis showed that clinical manifestations and surgical treatment of ossification of the ligamentum flavum accounted for a large proportion of study.(5)The timeline and burst analysis of keywords revealed that"minimally invasive surgery"appeared as a keyword around 2015,with the highest burst strength and the latest burst start time,and began to receive extensive attention from researchers in 2019.The burst of the keyword"dural ossification"has not yet ended.(6)Surgical treatment for ossification of the ligamentum flavum has been at the forefront of research.Development and research of minimally invasive surgery and research on dural ossification secondary to ossification of the ligamentum flavum are both current research hotspots and possible future research trends.

BACKGROUND:How to effectively promote bone regeneration and bone reconstruction after bone injury has always been a key issue in clinical bone repair research.The use of biological and degradable materials loaded with bioactive factors to treat bone defects has excellent application prospects in bone repair. OBJECTIVE:To investigate the effect of polylactic acid-glycolic acid copolymer(PLGA)composite scaffold modified by lysine-grafted graphene oxide nanoparticles(LGA-g-GO)on osteogenic differentiation and new bone formation. METHODS:PLGA was dissolved in dichloromethane and PLGA scaffold was prepared by solvent evaporation method.PLGA/GO composite scaffolds were prepared by dispersing graphene oxide uniformly in PLGA solution.LGA-g-GO nanoparticles were prepared by chemical grafting method,and the PLGA/LGA-g-GO composite scaffolds were constructed by blending LGA-g-GO nanoparticles at different mass ratios(1%,2%,and 3%)with PLGA.The micromorphology,hydrophilicity,and protein adsorption capacity of scaffolds of five groups were characterized.MC3T3 cells were inoculated on the surface of scaffolds of five groups to detect cell proliferation and osteogenic differentiation. RESULTS AND CONCLUSION:(1)The surface of PLGA scaffolds was smooth and flat under scanning electron microscope,while the surface of the other four scaffolds was rough.The surface roughness of the composite scaffolds increased with the increase of the addition of LGA-g-GO nanoparticles.The water contact angle of PLGA/LGA-g-GO(3%)composite scaffolds was lower than that of the other four groups(P<0.05).The protein adsorption capacity of PLGA/LGA-g-GO(1%,2%,and 3%)composite scaffolds was stronger than PLGA and PLGA/GO scaffolds(P<0.05).(2)CCK-8 assay showed that PLGA/LGA-g-GO(2%,3%)composite scaffold could promote the proliferation of MC3T3 cells.Alkaline phosphatase staining and alizarin red staining showed that the cell alkaline phosphatase activity in PLGA/LGA-g-GO(2%,3%)group was higher than that in the other three groups(P<0.05).The calcium deposition in the PLGA/GO and PLGA/LGA-g-GO(1%,2%,and 3%)groups was higher than that in the PLGA group(P<0.05).(3)In summary,PLGA/LGA-g-GO composite scaffold can promote the proliferation and osteogenic differentiation of osteoblasts,and is conducive to bone regeneration and bone reconstruction after bone injury.

BACKGROUND:Scholars at home and abroad consider New Zealand rabbits to be an ideal model animal because of the similar anatomical morphology of the lumbar spine to that of the human lumbar spine.There is a lack of systematic comparison of different ways to establish rabbit intervertebral disc degeneration models under X-ray guidance. OBJECTIVE:To establish a rabbit model of lumbar disc degeneration using X-ray guided acupuncture,end-plate injection and combined method,and to compare the modeling effects of these three methods. METHODS:Eighteen 6-month-old New Zealand white rabbits were randomly selected and divided into four groups:acupuncture group,endplate injection group,combined group and blank control group.In the acupuncture group,three consecutive segments of the intervertebral discs(L2/3,L3/4,L4/5)were needled and modeled;in the endplate injection group,50 μL of anhydrous ethanol was injected at a single point on the endplates of the three consecutive segmental discs;in the combined group,three consecutive segmental intervertebral discs were needled and injected with 50 μL of anhydrous ethanol at four azimuthal points on the endplates of the corresponding segmental discs;and the blank control group received no interventions.X-ray examination was performed to measure the disc height index at 2,4,and 8 weeks after surgery.The intervertebral disc tissues were then taken for anatomical observation and pathological examination. RESULTS AND CONCLUSION:(1)Anatomical examination showed that fibrous annulus rupture,nucleus pulposus degeneration,and total disc structure disorder were the main manifestation in the acupuncture group,endplate injection group,and combined group,respectively.(2)X-ray examination showed that the disc height index showed the most obvious reduction in the acupuncture group at 2 weeks after operation,significant reductions in the endplate injection group at 2 and 4 weeks after operation,and significant reductions in the combined group at 2,4,and 8 weeks after operation.(3)Pathological examination showed that the fibrous ring structure was damaged and the inner annulus fibrosus protruded inward in the acupuncture group;endplate fissure,disordered arrangement and nucleus loss were observed in the endplate injection group;total disc structure disorder with the nucleus pulposus losing water and shrinking and no obvious border with the broken annulus fibrosus was found in the combined group.To conclude,acupuncture,endplate injection and the modified endplate injection method can establish the rabbit intervertebral disc degeneration model.Compared with the single method,the modified endplate injection method can greatly accelerate and aggravate the degeneration of the intervertebral disc,and can effectively shorten the experiment period.

BACKGROUND:Agomelatine is a clinically proven treatment for neuropsychiatric symptoms,such as anxiety and depression.Furthermore,our previous study has demonstrated that agomelatine ameliorates cognitive behaviors,hippocampal synaptic plasticity,and brain pathology in a mouse model of Alzheimer's disease.However,it remains unclear whether agomelatine can improve anxiety and depression-like behaviors in Alzheimer's disease model mice. OBJECTIVE:To investigate the improving effects of agomelatine on anxiety-and depression-like behaviors in APP/PS1 transgenic mice and its underlying molecular mechanisms. METHODS:(1)Eighteen APP/PS1 transgenic mice were randomly divided into model control group(n=9)and model intervention group(n=9).Another wild-type mice were randomized into control group(n=9)and intervention group(n=9).Model intervention group and intervention group were intraperitoneally injected with 10 mg/kg agomelatine per day for 31 continuous days.Behavioral experiments,including the elevated cross maze and forced swimming tests,and mRNA sequencing of the hippocampus were then performed.(2)Mouse hippocampal neuronal cell lines(HT22)and brain microvascular endothelial cell lines(bEnd.3)were cultured and divided into four groups:blank group without any drug,drug group with 20 μmol/L agomelatine,model group with 10 μmol/L β-amyloid 1-42,and experimental group with 10 μmol/L β-amyloid 1-42+20 μmol/L agomelatine.After 24 hours of incubation,protein expression of S416p-tau and S9p-GSK3β in HT22 cells was detected by immunoblotting,and protein expression of low-density lipoprotein receptor-related protein 1 and glycosylation end-product receptor in bEnd.3 cells was detected by immunoblotting. RESULTS AND CONCLUSION:In the elevated plus maze test,the time spent in the open arms(P＜0.01)and the entries into open arms(P＜0.05)in the mice of model control group were evidently lower than those in the control group,whereas those were obviously increased in the model intervention group compared with the model control group(P＜0.05).Forced swimming test results showed that the immobile time exhibited a marked increase in the model control group compared with the control group(P＜0.05),but it was significantly decreased in the model intervention group compared with the model control group(P＜0.05).Hippocampal tissue mRNA sequencing showed that agomelatine enhanced the expression of low-density lipoprotein receptor-related protein 1 in the hippocampus of APP/PS1 mice.Western blot analysis revealed that the level of S416p-tau in HT22 cells was higher in the model group than the blank group(P＜0.05),while it was markedly decreased in the experimental group compared with the model group(P＜0.05);the level of S9p-GSK3β in HT22 cells was higher in the drug group than the blank group(P＜0.05)as well as higher in the experimental group than the model group(P＜0.05).Moreover,the expression of low-density lipoprotein receptor-related protein 1 in bEnd.3 cells was higher in the experimental group than the model group(P＜0.05).To conclude,agomelatine can alleviate anxiety-and depression-like behaviors in Alzheimer's disease mice by promoting the clearance of β-amyloid and phosphorylated tau.

BACKGROUND:Multiple studies have confirmed that mitogen-activated protein kinase(MAPK)signaling pathway is involved in cell proliferation,and microRNA(miR)is involved in the occurrence and development of hypertrophic scars.Therefore,the role of miR-27a-3p and MAPK signaling pathways in pathological scar formation has been further explored. OBJECTIVE:To explore the effect of miR-27a-3p on the proliferation of human hypertrophic scar fibroblasts through the MAPK signaling pathway. METHODS:The primary fibroblasts were isolated and collected from the skin samples.The primary fibroblasts were observed by inverted microscope and verified by immunofluorescence.The relative expression level of miR-27a-3p in tissues was detected by qRT-PCR.The target genes of hsa-miR-27a-3p were predicted using the database,and then the predicted target genes were enriched by gene ontology function analysis and biological pathway enrichment analysis of the Kyoto Encyclopedia of Genes and Genomes.There were seven groups:blank control,negative control,miR-27a-3p mimic,miR-27a-3p inhibitor,miR-27a-3p mimic+p38 MAPK inhibitor,miR-27a-3p mimic+extracellular regulated protein kinase inhibitor,miR-27a-3p mimic+c-Jun N-terminal kinase inhibitor.Western blot was used to detect the levels of extracellular regulated protein kinase,c-Jun N-terminal kinase inhibitor.and p38 kinase and their phosphorylation levels.Cell counting kit-8 and EdU were used to detect cell proliferation. RESULTS AND CONCLUSION:Compared with normal skin fibroblasts,hypertrophic scar fibroblasts had stronger proliferative activity(P<0.05)and faster proliferation level(P<0.001).Compared with normal skin,miR-27a-3p was highly expressed in hypertrophic scars(P<0.001).Compared with the negative control group,overexpression of miR-27a-3p could promote cell proliferation activity(P<0.001)and proliferation levels(P<0.001).Compared with the negative control group,knockdown of miR-27a-3p could inhibit the proliferation activity(P<0.05)and proliferation levels(P<0.001).Compared with the negative control group,overexpression of miR-27a-3p promoted the phosphorylated levels of extracellular regulated protein kinase,c-Jun N-terminal kinase,and p38 mitogen-activated protein kinase(P<0.05).Compared with the negative control group,knockdown of miR-27a-3p inhibited the phosphorylated levels of extracellular regulated protein kinase,c-Jun N-terminal kinase,and p38 MAPK(P<0.05).Compared with the miR-27a-3p mimic group,specific inhibitors of extracellular regulated protein kinase,c-Jun N-terminal kinase,and p38 MAPK reversed the effects of miR-27a-3p on the proliferative activity(P<0.01)and proliferation level(P<0.001)of fibroblasts.To conclude,these results suggest that miR-27a-3p promotes the proliferation of human hypertrophic scar fibroblasts by activating the MAPK signaling pathway.

BACKGROUND:Osteoporotic vertebral fractures are the most common complication in patients with osteoporosis.As a new imaging technique,spine magnetic resonance imaging(MRI)is much more sensitive than X-ray film in the diagnosis of osteoporotic vertebral fractures.However,total spine MRI is costly and takes a long time to scan.Therefore,there is no consensus on whether all patients with osteoporotic vertebral fractures need to undergo total spine MRI scan and which patients need to undergo total spine MRI. OBJECTIVE:To analyze the distribution characteristics of vertebral fractures and explore their clinical significance by observing the whole spine MRI data of osteoporotic vertebral fractures patients. METHODS:Data of cases and MRI images of all patients diagnosed with fresh osteoporotic vertebral fractures who visited the Department of Orthopedics,Affiliated Hospital of Southwest Medical University from August 2018 to September 2022 were retrospectively analyzed.903 patients were included in the study based on inclusion and exclusion criteria.General information(age,gender,and body mass index),medical history characteristics(duration of illness,history of trauma surgery,percussion pain area,and pain score)were collected.The characteristics of vertebral fractures were analyzed through whole spine magnetic resonance imaging.Firstly,based on the number of vertebral fractures in patients,they were divided into the single vertebral fracture group(484 cases)and the multi-vertebral fracture group(419 cases),and the differences were analyzed between the two groups.Then,based on whether the farthest interval between the fractured vertebrae was greater than or equal to 5,the multi vertebral fracture group was further divided into two subgroups.Among them,Group A(the farthest interval between the fractured vertebrae was less than 5)contained 306 cases;Group B(with the farthest interval between fractured vertebral bodies greater than 5)included 113 cases.The differences were analyzed between two subgroups. RESULTS AND CONCLUSION:(1)Among 903 patients,419 patients(46.4%)had more than two fractured vertebrae.There were 654 patients(72.4%)with thoracolumbar fractures,and 54 patients(6%)with fractures in the thoracic plus lumbar region and the entire thoracic to lumbar region.In group B,96.5%of patients had multiregional percussion pain.(2)Compared with the patients in the single vertebral fracture group and the multi-vertebral fracture group,there were significant differences in bone mineral density,whether the medical history was greater than or equal to 1 month,the history of low energy injury,and the distribution and number of axial percussion pain areas in the spine during physical examination between the two groups(P<0.05).Age,gender,body mass index,whether there was underlying disease,pain visual analog scale score,whether there was a history of elderly thoracolumbar fracture,and whether there was a history of thoracolumbar surgery,and the number of fractured vertebrae had no statistical significance(P>0.05).(3)There were statistically significant differences between the Groups A and B in bone mineral density,the distribution and quantity of percussion pain area,and the history of low energy injury(P<0.05).There were no significant differences in age,gender,history of old fractures,visual analog scale score,body mass index,whether the medical history was longer than or equal to 1 month,history of underlying diseases,and history of thoracolumbar surgery between the two groups(P>0.05).(4)Patients with multiple low-energy trauma history,history of more than 1 month,multiple percussion pain,and the lower bone mineral density should be alert to the occurrence of multiple vertebral fracture and jump fracture.We recommend the whole spinal MRI for these patients.

BACKGROUND:With the development of computer-aided design and computer-aided manufacturing technology,zirconia abutments with a titanium base are widely used in clinic due to its good application advantages,but there are still some problems and a lack of consensus design standards. OBJECTIVE:To review the fabrication methods of Ti-base zirconia abutment,and the effect of abutment connection,emergence design,abutment angle,and bonding on mechanical properties of Ti-base zirconia abutment. METHODS:Relevant literature published from 2010 to 2023 was searched in CNKI and PubMed databases with the search terms"zirconia abutment,titanium base"in Chinese and English,respectively.The search time limit was extended for some classical literature.The relevant literature was obtained through inclusion and exclusion criteria,and 57 eligible documents were included for review. RESULTS AND CONCLUSION:It is recommended that clinicians try to select antirotational titanium bases or rotational titanium bases with a Morse taper connection.Implants should be placed in the correct axial angulation of not more than 15° or with an inclination to the palatal side when using angled zirconia abutments.When a≥30° labial inclination is followed for implant placement,the bite force must be decreased effectively to reduce the risk of mechanical and biological complications of implants,abutments,and prostheses.Ti-base zirconia abutments with a higher gingival height should be selected,and its restorative angle should not exceed 40°.Multilink Hybrid Abutment could be the first choice for extraoral bonding of zirconia abutment to titanium bases.

BACKGROUND:Spleen has the functions of blood storage,hematopoiesis,and immunity.With the increase of age,the structural degeneration and functional decline of spleen lead to the impairment of immune system function,thus accelerating the aging process of the body.The treatment of spleen aging in tree shrews with highly active umbilical cord mesenchymal stem cells has not been reported. OBJECTIVE:To explore the intervention effect and mechanism of highly active umbilical cord mesenchymal stem cells on spleen aging in tree shrews. METHODS:Highly active umbilical cord mesenchymal stem cells were isolated,cultured,and obtained from the umbilical cord tissue of newborn tree shrews by caesarean section.The differentiation abilities of adipogenesis,osteogenesis,and chondrogenesis were detected by three-line differentiation kit.Cell cycle and surface markers were detected by flow cytometry.The second generation of highly active umbilical cord mesenchymal stem cells were transfected with Genechem Green Fluorescent Protein with infection complex values of 100,120,140,160,180,and 200,respectively,to screen the best transfection conditions.After transfection,the fourth generation of highly active umbilical cord mesenchymal stem cells was injected into the tail vein of tree shrews in the elderly treatment group.The young control group and the aged model group were not given special treatment.After 4 months of treatment,the spleen tissue was taken and the structure of the spleen was observed by hematoxylin-eosin staining.β-Galactosidase staining was used to detect the activity of aging-related galactosidase.Immunohistochemical staining was used to detect the expression levels of p21 and p53 proteins.Ki67 and PCNA immunofluorescence staining was used to detect cell proliferation activity.Immunofluorescence staining was used to detect the expression levels of spleen autophagy protein molecules Beclin 1 and APG5L/ATG5.Reactive oxygen species fluorescence staining was used to detect the content of reactive oxygen species in spleen tissue.CD3 immunofluorescence staining was used to detect the change of the proportion of total T lymphocytes.The secretion levels of interleukin 1β and transforming growth factor β1 in spleen were detected by enzyme linked immunosorbent assay.The distribution of highly active umbilical cord mesenchymal stem cells labeled with green fluorescent protein in spleen tissue was observed by DAPI double staining of nucleus. RESULTS AND CONCLUSION:(1)Highly active umbilical cord mesenchymal stem cells grew in a short spindle shape with fish-like growth,with a large proportion of G0/G1 phase,and had the potential to differentiate into adipogenesis,osteogenesis,and chondrogenesis.(2)Multiplicity of infection=140 and transfection for 72 hours were the best conditions for labeling tree shrews highly active umbilical cord mesenchymal stem cells with Genechem Green Fluorescent Protein.(3)Compared with the aged model group,in the aged treatment group,the spleen tissue cells of tree shrews were arranged closely,and the area of white pulp was increased(P<0.01);the boundary between red pulp and white pulp was clear;the proportion of germinal centers did not show statistically significant difference(P>0.05).The activity level of galactosidase related to spleen tissue aging was decreased(P<0.001),and the expression levels of aging protein molecules p21 and p53 were down-regulated(P<0.001).The expression levels of proliferation-related molecules Ki67 and PCNA were up-regulated(P<0.001,P<0.05);expression levels of autophagy-related molecules Beclin 1 and APG5L/ATG5 were up-regulated(P<0.001),and the content of reactive oxygen species decreased(P<0.001),and the proportion of CD3+T cells increased(P<0.05).The secretion level of interleukin 1β in the aging-related secretion phenotype decreased(P<0.001);no significant difference was found in transforming growth factor β1 level(P>0.05).Compared with the young control group,the above indexes were significantly different in the elderly treatment group(P<0.05).(4)Green fluorescent cells labeled with green fluorescent protein were observed in spleen tissue of tree shrews the elderly treatment group by frozen tissue section observation.The results show that intravenous infusion of highly active umbilical cord mesenchymal stem cells can migrate to spleen tissue,inhibit the production of reactive oxygen species,down-regulate the expression of aging-related proteins,induce autophagy,promote cell proliferation,reduce chronic inflammation,and then improve the structure and function of spleen tissue.