BACKGROUND:Aging of human body may be due to the senescence and depletion of various stem cells in the body.Bone marrow mesenchymal stromal cells have important physiological functions and have shown certain therapeutic effects on various diseases.It is of great significance to study the senescence and mechanism of bone marrow mesenchymal stromal cells.OBJECTIVE:To investigate whether human bone marrow mesenchymal stromal cells exhibit senescence phenotypes with increasing donor age,and further determine whether endogenous retrovirus drives the senescence of bone marrow mesenchymal stromal cells,offering a novel reference for the investigation of stem cell senescence mechanism.METHODS:The senescence of bone marrow mesenchymal stromal cells at different ages was characterized by flow cytometry,β-galactosidase staining,qPCR,western blotting,and EdU fluorescence imaging.Bone marrow mesenchymal stromal cells and cell culture supernatant were collected from donors of different ages.The content of human endogenous retrovirus was detected by qPCR.Furthermore,highly sensitive droplet digital PCR was used to detect the expression of endogenous retrovirus-like particles in the cell culture supernatant.The content of endogenous retrovirus in bone marrow plasma samples of different ages was detected by ELISA.RESULTS AND CONCLUSION:Bone marrow mesenchymal stromal cells exhibited obvious senescence with increasing age,including significant morphological changes,increased proportion of β-galactosidase positive cells,increased expression of senescence markers P16 and P21 protein,decreased expression of LMNB1 protein,and reduced cell proliferation ability.There was no significant difference in the content of endogenous retrovirus in bone marrow mesenchymal stromal cells at different ages,almost no endogenous retrovirus-like particles in the cell culture supernatant.There was no significant difference in endogenous retrovirus-like particles detected in bone marrow plasma samples at different ages.These findings indicate that human bone marrow mesenchymal stromal cells have normal physiological senescence with increasing age,but the mechanism of senescence is not mediated by abnormal activation of endogenous retroviruses,which may have a more complex driving mechanism.

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:Curcumin is the main active ingredient of turmeric and has significant medicinal value in anti-tumor,anti-inflammatory,antioxidant and other aspects.However,its poor water solubility,unstable chemical properties and easy decomposition lead to difficulty in extracting curcumin and low extraction yield.Therefore,it is particularly important to optimize the curcumin extraction method.OBJECTIVE:To enhance the extraction yield and utilization value of curcumin and optimize the curcumin extraction process and curcumin nanoparticle preparation process.METHODS:Curcumin was extracted from turmeric by ethanol extraction,ultrasonic extraction,ionic liquid extraction,enzyme extraction,and ionic liquid combined with ultrasonic assisted enzyme extraction.The curcumin extraction yield was detected by high performance liquid chromatography;the best extraction method was determined,and subsequent process optimization experiments were carried out.The curcumin extraction yield was the response value with the type of ionic liquid,reaction temperature,ultrasonic time,liquid-to-solid ratio,ionic liquid concentration,and enzyme-drug mass ratio as parameters.The optimal production process of ionic liquid combined with ultrasonic assisted enzyme extraction was determined by single factor combined response surface experiment.The optimal process for preparing curcumin nanoparticles by ionic crosslinking method was determined by single factor combined response surface experiment with acetic acid concentration,chitosan to sodium tripolyphosphate mass ratio,stirring rate,curcumin mass concentration,sodium tripolyphosphate mass concentration,and chitosan mass concentration as parameters,and drug encapsulation efficiency as response value.Curcumin nanoparticles were prepared under the optimal process,and the particle size,polydispersity index,Zata potential value,drug loading,stability,hemolysis rate,and antioxidant capacity in vivo and in vitro of the nanoparticles were detected.RESULTS AND CONCLUSION:(1)Among the five extraction methods,the curcumin yield of ionic liquid combined with ultrasound-assisted enzyme extraction was the highest,and this method was selected as the curcumin extraction method for subsequent experiments.The results of single factor combined response surface experiment showed that the optimal process for curcumin extraction was:ionic liquid selected 1-hexyl-3-methylimidazolium chloride,reaction temperature 55 ℃,liquid-to-solid ratio 40 mL/g,ultrasound time 57 minutes,ionic liquid concentration 57％,enzyme-drug mass ratio 3.5:10,and the obtained turmeric extraction yield was 3.10％.The optimal preparation process of curcumin nanoparticles was:glacial acetic acid concentration 0.5％,chitosan and sodium tripolyphosphate mass ratio 5.0:1,stirring speed 150 r/min,curcumin mass concentration 2.23 mg/mL,sodium tripolyphosphate mass concentration 1.45 mg/mL,chitosan mass concentration 3.63 mg/mL,and the obtained drug encapsulation efficiency was 90.61％.(2)The drug loading of curcumin nanoparticles was(14.49±0.23)％,the average particle size was(76.95±1.65)nm,the polydispersity coefficient was 0.15±0.02,and the Zata potential value was(32.37±1.46)mV.The curcumin nanoparticles had good stability and blood compatibility,did not induce hemolysis,and had stronger antioxidant capacity in vivo and in vitro than free curcumin.(3)The results show that the process optimization not only solves the problems of low extraction yield,poor solubility,and low bioavailability of curcumin,but also enhances its antioxidant activity in vivo and in vitro.

BACKGROUND:Titanium elastic intramedullary nailing for the treatment of significantly displaced midshaft clavicle fractures has the characteristics of minimally invasive and elastic fixation.The displacement of the fracture is closely related to the later function.However,there are few studies on the three-dimensional displacement analysis of the fracture ends before surgery and after intramedullary fixation such as titanium elastic intramedullary nailing.OBJECTIVE:To explore the three-dimensional displacement of fracture ends after midshaft clavicle fracture and fixation with titanium elastic intramedullary nails,and to analyze the risk factors.METHODS:A total of 91 patients with midshaft clavicle fracture(fracture end shortening ≥15 mm)admitted to Wendeng Orthopedic Hospital of Shandong Province from April 2019 to April 2024 were selected,including 57 males and 34 females,aged(51.73±10.21)years old.All patients received closed reduction and internal fixation with titanium elastic intramedullary nail.CT scans of the affected clavicle were performed before and on the first day after surgery.The CT data were imported into Mimics software for modeling.The length of the clavicle,lateral displacement of the fracture end,and rotation of the distal end of the fracture along the X,Y,and Z axes were measured and recorded before and after surgery.Pearson correlation coefficient was used for correlation analysis of various parameters,and generalized linear regression was used to evaluate risk factors.RESULTS AND CONCLUSION:(1)Preoperatively,the variable that increased the risk of lateral displacement was the number of comminuted bone fragments,the variable that increased the risk of shortening displacement was male patients,and the variable that increased the risk of Z-axis rotation was the left limb.Shortening displacement was significantly positively correlated with lateral displacement(r=0.715,P＜0.001);shortening displacement was significantly positively correlated with X-axis rotation displacement and Y-axis rotation displacement(r=0.265,P=0.028;r=0.303,P=0.011);lateral displacement was significantly positively correlated with Y-axis rotation and Z-axis rotation(r=0.258,P=0.032;r=0.250,P=0.038);X-axis rotation was significantly positively correlated with Y-axis rotation(r=0.382,P=0.001),and Z-axis rotation was significantly positively correlated with Y-axis rotation(r=0.280,P=0.020).(2)Postoperatively:The number of scapula fractures and comminuted bone fragments were variables that increased the risk of postoperative shortening and lateral displacement:Preoperative X-,Y-,and Z-axis rotation displacements were risk variables that increased postoperative X-,Y-,and Z-axis rotation displacements,respectively.Postoperative lateral displacement was significantly positively correlated with postoperative shortening and displacement(r=0.584,P=0.000),and postoperative lateral displacement was also significantly positively correlated with postoperative Y axis rotation and Z axis rotation(r=0.360,P=0.002;r=0.250,P=0.038).Postoperative Y axis rotation was significantly positively correlated with postoperative Z axis rotation(r=0.248,P=0.040).(3)The results showed that the three-dimensional displacement of the clavicle end before and after surgery was affected by many factors,especially the number of comminuted bone fragments,scapula fractures,gender,and original rotation displacement.At the same time,there were complex correlations between various displacements,especially the correlation between shortening displacement and lateral displacement was the strongest.

BACKGROUND:Dental mesenchymal stem cells are considered a promising source for bone tissue repair due to their high proliferation potential,osteogenic differentiation capacity,and immunomodulatory properties.However,some allogeneic applications of stem cells still have potential carcinogenic effects and immune rejection risks.Recently,studies have highlighted the paracrine effects mediated by secretions from dental mesenchymal stem cells in bone tissue repair.These secretions include the soluble factors and extracellular vesicles.OBJECTIVE:To review the research progress of dental mesenchymal stem cells in repairing bone defects through paracrine effects.METHODS:Using search terms"dental mesenchymal stem cell,paracrine,osteogenesis,conditioned medium,extracellular vesicle"in Chinese and English,relevant literature published between 2019 and 2024 was retrieved from databases including CNKI,PubMed,and Elsevier ScienceDirect.A total of 104 studies were ultimately selected for this review.RESULTS AND CONCLUSION:(1)Dental mesenchymal stem cells-conditioned medium contains multiple bioactive factors beneficial for bone repair.These factors directly promote bone formation through regulatory agents such as osteocalcin,osteopontin,bone morphogenetic protein,and dentin sialophosphoprotein.They also play an indirect promoting role in bone tissue repair through neurotrophic factors,vascular endothelial growth factor,and immunomodulatory and anti-inflammatory agents.(2)Dental derived mesenchymal stem cell-derived extracellular vesicles not only contain some cytokines from dental conditioned medium,but also various miRNAs,which promote bone repair by directly promoting osteogenesis,angiogenesis,regulating immune cells,and inflammation control.These extracellular vesicles can be engineered within different scaffold materials to achieve controlled or sustained release,enhancing therapeutic efficacy.

BACKGROUND:Currently,treatment method for knee osteoarthritis includes oral medicine,joint cavity drug injection,and physiotherapy,but the curative effect is limited.Existing studies have confirmed that silicon-based bioceramics can promote cartilage and subchondral bone repair and vascular regeneration.OBJECTIVE:To explore the effect of different concentrations of silicon-based bioceramics injected into the knee joint cavity in the treatment of knee osteoarthritis in rats.METHODS:Silicon-based bioceramics-calcium silicate was prepared.Twenty-five SD rats were randomly divided into five groups,with five rats in each group.The healthy group did not receive any intervention,and the modeling group,low-dose calcium silicate group,high-dose calcium silicate group,and saline group used anterior cruciate ligament transection to establish bilateral knee osteoarthritis models.Four weeks after modeling,0.05 mL of 50 and 100 mg/mL calcium silicate solution were injected into the knee joint cavity in the low-dose calcium silicate group and high-dose calcium silicate group,respectively,and 0.05 mL of saline was injected into the knee joint cavity in the saline group,once a week for 4 consecutive weeks.In the fifth week of administration,bilateral knee joint Micro-CT detection,knee joint cartilage hematoxylin-eosin staining,and modified Mankin score were performed.RESULTS AND CONCLUSION:(1)Micro-CT quantitative analysis showed that compared with the healthy group,the volume fraction and number of trabeculae of the medial tibial plateau in the modeling group decreased(P＜0.05),and the separation of trabeculae increased(P＜0.05).Compared with the modeling group,the volume fraction and number of trabeculae of the medial tibial plateau in the low-dose calcium silicate group and the saline group increased(P＜0.05),and the separation of trabeculae decreased(P＜0.05).(2)Hematoxylin-eosin staining showed that the cartilage surface of the healthy group and the low-dose calcium silicate group was relatively smooth and flat,the chondrocytes were evenly distributed,without clustered chondrocytes,the tide line was complete,and the staining was uniform;the cartilage surface of the high-dose calcium silicate group was slightly uneven,the middle and deep cells were disordered,with a small number of clustered chondrocytes,the tide line was discontinuous,and the staining was uneven;the cartilage surface of the saline group and the modeling group was obviously rough,the cells were disordered,with a large number of clustered chondrocytes,the tide line disappeared,and the staining was uneven.The modified Mankin score of the healthy group was lower than that of the high-dose calcium silicate group,the saline group,and the modeling group(P＜0.05).The modified Mankin score of the high-dose calcium silicate group and the low-dose calcium silicate group was lower than that of the saline group and the modeling group(P＜0.05).(3)The results show that calcium silicate knee joint injection has a certain effect in the treatment of knee osteoarthritis.Compared with 100 mg/mL calcium silicate solution,50 mg/mL calcium silicate solution can promote the recovery of subchondral bone and cartilage.

BACKGROUND:Studies have shown that platelet-derived growth factor BB can stimulate the proliferation and osteogenic differentiation of mesenchymal stem cells and accelerate the calcification process of osteoblast-like cells.However,its clinical application has problems such as short half-life and easy decomposition.Loading the growth factor onto a suitable biomaterial scaffold can enable its slow and continuous release and maintain an effective concentration,which has become a hot topic in current research.OBJECTIVE:To observe the effect of chitosan/reduced graphene oxide scaffolds loaded with platelet-derived growth factor BB on the repair of alveolar bone defect in rats.METHODS:(1)Chitosan/reduced graphene oxide scaffolds(referred to as CS/rGO scaffolds)and chitosan/reduced graphene oxide scaffolds loaded with different mass concentrations(5,10,15,and 20 mg/L)of platelet-derived growth factor BB(referred to as CS/rGO/PDGF-BB-5,CS/rGO/PDGF-BB-10,CS/rGO/PDGF-BB-15,and CS/rGO/PDGF-BB-20 scaffolds)were prepared respectively.The five groups of scaffolds were co-cultured with rat periodontal ligament stem cells.The cell proliferation and migration were detected by CCK-8 assay and Transwell chamber assay,respectively,to screen the appropriate growth factor loading mass concentration for subsequent experiments.CS/rGO scaffolds(or extracts)and CS/rGO/PDGF-BB-15 scaffolds(or extracts)were co-cultured with rat periodontal ligament stem cells,and the osteogenic differentiation and angiogenic ability of the cells were detected.(2)The alveolar bone defect model was prepared in front of the bilateral maxillary first molars of 16 SD rats,and the rats were randomly divided into 4 intervention groups:the blank control group did not receive any intervention,the simple scaffold group was implanted with CS/rGO/PDGF-BB-15 scaffold,the control group was implanted with CS/rGO scaffold and rat periodontal ligament stem cell complex,and the experimental group was implanted with CS/rGO/PDGF-BB-15 scaffold and rat periodontal ligament stem cell complex,with 4 rats in each group.Twelve weeks after surgery,the bone repair of the alveolar bone defect was observed by Micro CT scanning and hematoxylin-eosin staining.RESULTS AND CONCLUSION:(1)CS/rGO/PDGF-BB-5,CS/rGO/PDGF-BB-10,CS/rGO/PDGF-BB-15,and CS/rGO/PDGF-BB-20 scaffolds could promote the proliferation and migration of rat periodontal ligament stem cells.Among them,the CS/rGO/PDGF-BB-15 scaffold had the most significant effect on promoting cell proliferation and migration,and this scaffold was used for subsequent experiments.Compared with the CS/rGO scaffold,the CS/rGO/PDGF-BB-15 scaffold could promote the osteogenic and angiogenic differentiation of rat periodontal ligament stem cells.(2)Micro CT scanning and hematoxylin-eosin staining results showed that the experimental group had the best alveolar bone defect repair effect,and a large amount of new bone tissue and blood vessel formation could be seen.(3)The chitosan/reduced graphene oxide scaffold loaded with platelet-derived growth factor BB can effectively promote the repair of rat alveolar bone defects by promoting the proliferation,migration,angiogenic and osteogenic differentiation of rat periodontal ligament stem cells.

BACKGROUND:Magnetic nanomaterials,as a hot topic in the biomedical field in recent years,are often used to enhance the targeted delivery of drugs to the affected area.OBJECTIVE:To investigate the effects of magnetic nano drug carriers on skeletal muscle injury markers and inflammatory responses in rats with sports injuries.METHODS:Magnetic nanoparticles were prepared.A total of 88 male SD rats were randomly divided into a blank group(n=8),an injury control group(n=32),a Yunnan Baiyao group(n=24),and a magnetic nano-drug carrier group(n=24)by using a random number table method.The latter three groups were modeled with exercise-induced muscle injury(treadmill slope of-16°,running speed of 16 m/min,and training time of 120 min).Immediately after exercise,after verifying the success of the model,Yunnan Baiyao patch was applied to the gastrocnemius muscle of the rats in the Yunnan Baiyao group.Yunnan Baiyao patch loaded with magnetic nanoparticles was applied to the gastrocnemius muscle of the rats in the magnetic nano-drug carrier group.At 24,48,and 120 hours after exercise,blood was drawn from the abdominal aorta of rats to detect the activities of creatine kinase and lactate dehydrogenase,as well as the levels of myoglobin,interleukin-6,and tumor necrosis factor-α.Hematoxylin-eosin staining was used to observe the infiltration of inflammatory cells in the gastrocnemius muscle.RESULTS AND CONCLUSION:(1)Compared with the blank group,the levels of myoglobin,creatine kinase,lactate dehydrogenase and tumor necrosis factorα in the injury control group at 24,48 and 120 hours after exercise were increased(P＜0.05),and the level of interleukin 6 at 24 and 120 hours after exercise was increased(P＜0.05).Compared with the injury control group,the level of myoglobin in the Yunnan Baiyao group at 24 and 48 hours after exercise was decreased(P＜0.05),the activities of creatine kinase and lactate dehydrogenase at 24,48 and 120 hours were decreased(P＜0.05),and the levels of interleukin 6 and tumor necrosis factor α at 120 hours after exercise were decreased(P＜0.05).Compared with the Yunnan Baiyao group,the level of myoglobin in the magnetic nano-drug carrier group at 24 and 48 hours after exercise was decreased(P＜0.05),the activities of creatine kinase and tumor necrosis factor α at 48 and 120 hours after exercise were decreased(P＜0.05),and the lactate dehydrogenase activity was reduced(P＜0.05).(2)Hematoxylin-eosin staining showed that a large number of inflammatory cells infiltrated in the muscle fibers of the injury control group 24 hours after exercise,and then the inflammatory cell infiltration gradually decreased,and the local damaged muscle fibers began to regenerate 120 hours after exercise.A large number of inflammatory cells infiltrated in the muscle fibers of the Yunnan Baiyao group and the magnetic nano-drug carrier group 24 hours after exercise,and then the inflammatory cell infiltration gradually decreased,and the damaged muscle fibers were regenerating 120 hours after exercise,and there was no significant difference from the blank group.(3)The results show that Yunnan Baiyao patch combined with magnetic nanoparticles can accelerate the recovery of exercise-induced muscle injury in rats,and the effect is better than that of Yunnan Baiyao alone.

BACKGROUND:Orthodontic treatment to move the mandibular second molar in place of the missing first molar is a good method for preserving natural teeth.However,molars often exhibit mesial tipping when using clear aligners.The impact of attachments and overcorrection on the molar mesialization with clear aligners is unclear.OBJECTIVE:To investigate the effects of attachments and overcorrection on displacement and biomechanics of the mandibular second molar mesialization.METHODS:A finite element model with the left mandibular first molar missing was constructed using a volunteer's cone-beam CT and intraoral scan data.The experiment was divided into four groups based on the position of attachments on the left mandibular second molar:without attachment,buccal attachment,lingual attachment,and buccal-lingual attachment,with overcorrection degrees(0°,1°,2°,3°,and 4°)for each group,totaling 20 models.The calculation and analysis of the displacement trends and stress were performed using Abaqus software.RESULTS AND CONCLUSION:(1)Mesial tipping and intrusion of the molar,distal tipping of the canines and permolars,and linguaing of the incisors occurred during molar mesialization.(2)The displacement of molars increased when attachments were used,with the maximum displacement occurring when buccal-lingual attachments were applied.Molars tended to tip towards the side without attachments when attachments were designed unilaterally.However,the inclination of molars did not decrease when attachments were used.(3)Molars exhibited reduced mesial tipping and intrusion,approaching overall movement,and the stress of periodontal ligament was relieved and more evenly distributed during overcorrection treatment,and this effect became more pronounced with increased degrees of overcorrection.(4)Attachments can enhance the effectiveness of overcorrection,with the best performance observed when buccal-lingual attachments are used.Using attachments and overcorrection together helps control molar mesial tipping and intrusion,but overall molar movement is not achieved.

BACKGROUND:Currently,there are many modeling methods for pelvic organ prolapse animal models,and the commonly used methods are vaginal balloon dilatation,oophorectomy and the combination of the two.There is no study comparing the three modeling methods in detail.OBJECTIVE:To construct and validate a rat animal model of pelvic organ prolapse using three different methods and to identify the advantages and disadvantages of various models.METHODS:Seventy-two 8-week SPF-grade female Sprague-Dawley rats were selected and randomly divided into four groups,namely,vaginal balloon dilatation group,ovariectomy group,ovariectomy combined with vaginal balloon dilatation group(the combined group),and the sham-operated group(no ovariectomy and no vaginal dilatation).The vaginal wall tissues of rats were collected at 4,8 and 12 weeks after the operation for hematoxylin-eosin staining,Masson staining,EVG staining and immunohistochemical staining of α-smooth muscle actin,Vimentin and matrix metalloproteinase 9 detection,and the pelvic floor muscle tissues were taken at 4,8 and 12 weeks after the operation for hematoxylin-eosin staining,Masson staining and EVG staining.RESULTS AND CONCLUSION:(1)Hematoxylin-eosi staining showed that there was no significant difference in the decrease of vaginal epithelial layer thickness in the vaginal balloon dilatation group compared with the sham-operated group,(P＞0.05),while the thickness of the vaginal epithelial layer was significantly reduced in the ovariectomy group and the ovariectomy combined with vaginal balloon dilation group(P＜0.001),and the reduction was more significant in the ovariectomy combined with vaginal balloon dilation group,remained stable at 8 weeks after surgery and lasted until 12 weeks.(2)The changes in the content of collagen fibers and elastic fibers in the vaginal wall stained by Masson and EVG staining were the same as the changes in the thickness of the vaginal epithelial layer stained by hematoxylin-eosin,and there were no changes in collagen fibers and elastic fibers in the pelvic floor muscle tissues of the treatment groups.(3)At 4,8 and 12 weeks after treatment,there was no significant difference in the expression levels of α-smooth muscle actin,Vimentin and matrix metalloproteinase 9 in the vaginal wall tissue of the balloon dilation group compared with the control group(P＞0.05),whereas the expression levels of α-smooth muscle actin and Vimentin were significantly decreased in the ovariectomy group and ovariectomy combined with vaginal balloon dilation group(P＜0.01)and the expression of matrix metalloproteinase 9 showed a significant increase(P＜0.01),with a more pronounced increase in the ovariectomy combined with vaginal balloon dilation group,and the increase reached a stable state at 8 weeks after surgery and could persist up to 12 weeks.To conclude,vaginal balloon dilatation could not maintain the degeneration of pelvic organ prolapse formed by the vaginal wall for a long period,and both ovariectomy and the combined method can be used.Ovariectomy combined with vaginal balloon dilatation can significantly accelerate and aggravate the formation of typical histological features of pelvic organ prolapse in vaginal wall tissues,effectively shorten the experimental period,and improve the efficiency.These effects reach a stable state at 8 weeks after surgery and can be sustained up to 12 weeks,which is practical and convenient for the study of pelvic organ prolapse animal models.