OBJECTIVE: To prepare clinical-grade human umbilical cord-derived mesenchymal stem cells (hUC-MSC) with high expression of hematopoietic supporting factors and evaluate their stem cell characteristics. METHODS: Fetal umbilical cord tissues were collected from healthy postpartum women during full-term cesarean section. Wharton's jelly was mechanically separated and hUC-MSCs were obtained by explant culture method and enzyme digestion method in an animal serum-free culture system with addition of human platelet lysate. The phenotypic characteristics of hUC-MSCs obtained by two methods were detected by flow cytometry. The differences in proliferation ability between the two groups of hUC-MSCs were identified through CCK-8 assay and colony forming unit-fibroblast (CFU-F) assay. The differences in multilineage differentiation potential between the two groups of hUC-MSCs were identified through induction of adipogenic, osteogenic, and chondrogenic differentiation. The mRNA expression levels of hematopoietic supporting factors such as SCF, IL-3, CXCL12, VCAM1 and ANGPT1 in the two groups of hUC-MSCs were identified by real-time fluorescence quantiative PCR(RT-qPCR). RESULTS: The results of flow cytometry showed that hUC-MSCs obtained by the two methods both expressed high levels of CD73, CD90 and CD105, while lowly expressed CD31, CD45 and HLA-DR. The results of CCK-8 and CFU-F assay showed that the proliferation ability of hUC-MSCs obtained by explant culture method was better than those obtained by enzyme digestion method. The results of the triple lineage differentiation experiment showed that there was no significant difference in multilineage differentiation potential between the two grous of hUC-MSCs. The results of RT-qPCR showed that the mRNA expression levels of hematopoietic supporting factors SCF, IL-3, CXCL12, VCAM1 and ANGPT1 in hUC-MSCs obtained by explant cultrue method were higher than those obtained by enzyme digestion method. CONCLUSION Clinical-grade hUC-MSCs with high expression levels of hematopoietic supporting factors were successfully cultured in an animal serum-free culture system.
Humans ; Mesenchymal Stem Cells/metabolism* ; Umbilical Cord/cytology* ; Cell Differentiation ; Female ; Cell Proliferation ; Cells, Cultured ; Chemokine CXCL12/metabolism* ; Angiopoietin-1/metabolism* ; Vascular Cell Adhesion Molecule-1/metabolism* ; Stem Cell Factor/metabolism* ; Flow Cytometry ; Pregnancy

OBJECTIVE: To investigate the effects of Bushen Huoxue Granule on the ubiquitin-proteasome system (UPS) in an in vitro model of Parkinson's disease. METHODS: After treated with 1-methyl-4-phenylpyridinium (MPP⁺, 1 mmol/L) for 24 h, the cells were incubated with drug-free serum, Madopar-containing serum or Bushen Huoxue Granule-containing serum (BCS, 5%, 10%, and 20%) for another 24 h. The levels of α-synuclein (α-syn), tyrosine hydroxylase (TH) and UPS-related proteins were detected by Western blot. The expression levels of α-syn in PC12 cells were also analyzed by Western blot after treated with proteasome inhibitor MG132 and WT-α-syn plasmid transfection, respectively, as well as the alterations induced by subsequent BCS intervention. Immunocytochemistry was performed to determine the changes in α-syn phosphorylation at serine 129 (pSer129-α-syn) expression. The 20S proteasome levels were measured by enzyme-linked immunosorbnent assay. RESULTS: BCS (volume fraction ⩽20%) intervention could alleviate the MMP⁺-induced cell viability decrease (P<0.05). In the MPP⁺ treated cells, α-syn was up-regulated, while TH and proteins of UPS such as ubiquitin (Ub), Ub binding with Ub-activating enzyme (UBE1), Parkin and Ub C-terminal hydrolase-1 (UCHL-1) were down-regulated (P<0.05). BCS intervention could attenuate the above changes (P<0.05). The activity of BCS on blocking α-syn accumulation was weakened by MG132 (P<0.05). While α-syn level was significantly increased in cells transfected with plasmid, and reduced by BCS intervention (P<0.05). pSer129-α-syn was increased in MPP⁺-induced PC12 cells, whereas decreased by later BCS intervention (P<0.05). The 20S proteasome activity of MPP⁺-induced PC12 cells was decreased, but increased after BCS intervention (P<0.05). CONCLUSION BCS intervention protected UPS function, increased 20S proteasome activity, promoted pathological α-syn clearance, restored cell viability, and reversed the damage caused by MPP⁺ in the in vitro model of Parkinson's disease.
PC12 Cells ; alpha-Synuclein/metabolism* ; Rats ; Animals ; 1-Methyl-4-phenylpyridinium/toxicity* ; Proteasome Endopeptidase Complex/metabolism* ; Drugs, Chinese Herbal/pharmacology* ; Ubiquitin/metabolism* ; Cell Survival/drug effects* ; Phosphorylation/drug effects* ; Tyrosine 3-Monooxygenase/metabolism*

OBJECTIVE: This study examines the sequential mediating roles of body pain and self-reported health in the association between sleep duration and self-reported life satisfaction among elderly Chinese adults. METHODS: Data from the fifth wave of the China Health and Retirement Longitudinal Survey (CHARLS) were used to analyse the relationships between sleep duration and body pain, self-reported health, and life satisfaction through logistic regression and Restricted Cubic Spline (RCS) analyses. The sequential mediation effects of body pain and self-reported health status were examined via chain mediation analysis. RESULTS: Logistic regression analysis showed that sleeping fewer than 6 hours or 6-7 hours was linked to higher risks of body pain, poor health, and dissatisfaction with life compared to sleeping 7-8 hours (all P < 0.05). Additionally, those sleeping more than 9 hours also had increased risks of poor health and dissatisfaction with life compared to those sleeping 7-8 hours (all P < 0.05). Chain mediation analysis showed that body pain and self-reported health status sequentially mediated 46.15% of the association between sleep duration and life satisfaction. CONCLUSION Body pain and self-reported health may shape the relationship between sleep duration and life satisfaction in elderly Chinese adults.
Humans ; Male ; Female ; Aged ; Personal Satisfaction ; Sleep ; Health Status ; Self Report ; China ; Middle Aged ; Longitudinal Studies ; Pain/psychology* ; Sleep Duration

OBJECTIVE: To evaluate the effects of posterior cruciate ligament(PCL) resection on soft tissue elasticity and knee stability in total knee arthroplasty(TKA). METHODS: Six adult cadaveric knee specimens (involving 10 knees) were included in the study. With the assistance of the robotic system(TiRobot Recon, TINAVI, Beijing), total knee arthroplasty (TKA) was performed sequentially using cruciate retaining (CR) prostheses and posterior stabilizing (PS) prostheses. Between the two surgical procedures, the femoral and tibial osteotomy surfaces were not altered;only the posterior cruciate ligament (PCL) was resected and the intercondylar fossa was treated. After installing the femoral trial component, a soft tissue balance solver was used to apply tension ranging from 30 N to 90 N in 5 N increments at 0°, 10°, and 90° of knee flexion. Meanwhile, the medial and lateral joint gaps were measured synchronously. Based on the tension-gap coupling data, the equivalent elastic coefficients of the medial and lateral soft tissue sleeves at different knee flexion angles, as well as the range of the joint line convergence angle (JLCA) under fixed varus-valgus stress, were calculated. Additionally, the gap balance status under 80 N of tension was analyzed. Self-control comparisons of each indicator were conducted before and after PCL resection to analyze the change patterns. RESULTS: After PCL resection, in the fully extended position (knee flexion 0°). The medial equivalent elastic coefficient was 32.2 (25.7, 63.3) N·mm^-1 for the CR prosthesis and 27.7 (22.0, 51.9) N·mm^-1 for the PS prosthesis, and the statistically significant difference (P=0.013). The range of JLCA was 0.41°(0.26, 0.55)° for the CR prosthesis, which was smaller than 0.75° (0.40, 0.98)° for the PS prosthesis, and the difference was statistically significant(P=0.041). At 90° of knee flexion, the medial joint gap was 10.7(10.1, 11.7) mm for the CR prosthesis, which was smaller than 12.1(10.9, 15.1) mm for the PS prosthesis, with a statistically significant difference(P=0.011). No statistically significant differences were observed in other joint gaps. CONCLUSION PCL resection reduces the rigidity of the medial soft tissues in the fully extended knee and increases the medial joint gap in the flexed position, thereby affecting knee stability and balance. This finding suggests that PS and CR prostheses may require different morphological designs, and there should be differences in indications and osteotomy strategies between CR-TKA and PS-TKA. CR-TKA is more suitable for patients with preoperative medial soft tissue laxity.
Humans ; Posterior Cruciate Ligament/physiopathology* ; Knee Joint/physiopathology* ; Arthroplasty, Replacement, Knee ; Elasticity ; Male ; Female ; Middle Aged ; Aged ; Biomechanical Phenomena ; Adult

PURPOSE: Intertrochanteric fractures undergoing proximal femoral nail antirotation (PFNA) surgery are associated with significant hidden blood loss. This study aimed to explore whether intramedullary administration of tranexamic acid (TXA) can reduce bleeding in PFNA surgery for intertrochanteric fractures in elderly individuals. METHODS: A randomized controlled trial was conducted from January 2019 to December 2022. Patients aged over 60 years with intertrochanteric fractures who underwent intramedullary fixation surgery with PFNA were eligible for inclusion and grouped according to random numbers. A total of 249 patients were initially enrolled, of which 83 were randomly allocated to the TXA group and 82 were allocated to the saline group. The TXA group received intramedullary perfusion of TXA after the bone marrow was reamed. The primary outcomes were total peri-operative blood loss and post-operative transfusion rate. The occurrence of adverse events was also recorded. Continuous data was analyzed by unpaired t-test or Mann-Whitney U test, and categorical data was analyzed by Pearson Chi-square test. RESULTS: The total peri-operative blood loss (mL) in the TXA group was significantly lower than that in the saline group (577.23 ± 358.02 vs. 716.89 ± 420.30, p = 0.031). The post-operative transfusion rate was 30.67% in the TXA group and 47.95% in the saline group (p = 0.031). The extent of post-operative deep venous thrombosis and the 3-month mortality rate were similar between the 2 groups. CONCLUSION We observed that intramedullary administration of TXA in PFNA surgery for intertrochanteric fractures in elderly individuals resulted in less peri-operative blood loss and decreased transfusion rate, without any adverse effects, and is, thus, recommended.
Humans ; Tranexamic Acid/administration & dosage* ; Hip Fractures/surgery* ; Male ; Aged ; Female ; Fracture Fixation, Intramedullary/adverse effects* ; Blood Loss, Surgical/prevention & control* ; Antifibrinolytic Agents/administration & dosage* ; Aged, 80 and over ; Bone Nails ; Middle Aged ; Blood Transfusion/statistics & numerical data*

Objective:To develop habitat radiomics models to predict early treatment responses to the hepatic arterial infusion chemotherapy (HAIC) combined with targeted therapy or immunotherapy in advanced hepatocellular carcinoma (HCC) patients, and to guide clinical diagnosis and treatment.Methods:From October 2021 to Decemeber 2023, at Army Characteristic Medical Center of PLA (Chongqing Daping Hospital) and the First Affiliated Hospital of Chongqing Medical University, 94 patients with advanced HCC who received HAIC combined with targeted therapy or immunotherapy were retrospectively enrolled. According to the treatment results, the patients were divided into response group and non-response group. Univariate and multivariate logistic regression were performed to analyze the clinical data of the patients. Based on contrast-enhanced CT images, tumor habitats were delineated and habitat features were extracted with k-means clustering, and the imaging features of arterial and venous phases were also extracted. The least absolute shrinkage and selection operator (LASSO) was used for dimensionality reduction. Feature selection was performed using LASSO to reduce dimensions, and then the selected features were further refined through stepwise logistic regression analysis.Binary logistic regression models were conducted to develop the habitat radiomics model, arterial phase radiomics model (APRM), venous phase radiomics model (VPRM), clinical data model, as well as the combination of radiomics model and clinical data model to predict early treatment (after 2 treatment cycles) response. Receiver operating characteristic curves (ROC) were plotted, and model performance was evaluated by the area under the curve (AUC), calibration curves, and decision curve. The models were validated through Bootstrap methods (1 000 times). DeLong test was used to compare AUC values.Results:The results of cluster analysis identified 3 characteristic habitats in HCC imaging: low-, medium-, and high-enhancement tumor habitats. The proportion of high-enhancement habitats was higher than that in the non-response group. A predictive model was established based on the proportions of these 3 habitats. Based on the proportion of low-, medium-, and high-enhancement habitats within the tumor, a habitat radiomics model was constructed. After LASSO selection and logistic regression analysis, 3 arterial phase and 3 venous phase radiomic features were selected to build the APRM and VPRM, respectively. Logistic regression analysis identified the following factors for the clinical data model: comorbidities ( OR=0.275, P=0.031), maximum tumor diameter ( OR=1.149, P=0.019), red blood cell count ( OR=0.463, P=0.022), alpha fetoprotein >400 μg/L ( OR=3.452, P=0.017), and tyrosine kinase inhibitor therapy ( OR=3.072, P=0.048). Among the single predictive model′s comparison, the AUC of habitat radiomics model was 0.860 (95% confidence interval(95% CI): 0.789 to 0.932), while those of the APRM、VPRM and clinical data model were 0.850 (95% CI: 0.773 to 0.926), 0.855 (95% CI: 0.782 to 0.928), and 0.774 (95% CI: 0.681 to 0.867), respectively, and there were no statistically significant among these models (all P>0.05). Among the combination models, the AUC of the habitat rediomic-clinical data combination model was 0.881 (95% CI: 0.814 to 0.947); the AUC of arterial phase rediomic-clinical data combination model was 0.897 (95% CI: 0.833 to 0.961); and the AUC of venous phase rediomic-clinical data combination model was 0.888 (95% CI: 0.826 to 0.951), but there were no statistically significant among the 3 models (all P>0.05). The calibration curve showed that the habitat rediomic-clinical data combination model had the most accurate predictive probability. Internal validation showed that the AUC of habitat rediomic-clinical data combination model was 0.848 (95% CI: 0.772 to 0.922), and the predictive performance was better than that of the clinical-data model (0.733 (95% CI: 0.670 to 0.863)). Conclusion:The habitat radiomics model based on enhanced CT can effectively predict early treatment responses to the HAIC combined with targeted therapy or immunotherapy in advanced HCC patients, which provides theoretical basis for individualized treatment in advanced HCC.

Objective:To develop habitat radiomics models to predict early treatment responses to the hepatic arterial infusion chemotherapy (HAIC) combined with targeted therapy or immunotherapy in advanced hepatocellular carcinoma (HCC) patients, and to guide clinical diagnosis and treatment.Methods:From October 2021 to Decemeber 2023, at Army Characteristic Medical Center of PLA (Chongqing Daping Hospital) and the First Affiliated Hospital of Chongqing Medical University, 94 patients with advanced HCC who received HAIC combined with targeted therapy or immunotherapy were retrospectively enrolled. According to the treatment results, the patients were divided into response group and non-response group. Univariate and multivariate logistic regression were performed to analyze the clinical data of the patients. Based on contrast-enhanced CT images, tumor habitats were delineated and habitat features were extracted with k-means clustering, and the imaging features of arterial and venous phases were also extracted. The least absolute shrinkage and selection operator (LASSO) was used for dimensionality reduction. Feature selection was performed using LASSO to reduce dimensions, and then the selected features were further refined through stepwise logistic regression analysis.Binary logistic regression models were conducted to develop the habitat radiomics model, arterial phase radiomics model (APRM), venous phase radiomics model (VPRM), clinical data model, as well as the combination of radiomics model and clinical data model to predict early treatment (after 2 treatment cycles) response. Receiver operating characteristic curves (ROC) were plotted, and model performance was evaluated by the area under the curve (AUC), calibration curves, and decision curve. The models were validated through Bootstrap methods (1 000 times). DeLong test was used to compare AUC values.Results:The results of cluster analysis identified 3 characteristic habitats in HCC imaging: low-, medium-, and high-enhancement tumor habitats. The proportion of high-enhancement habitats was higher than that in the non-response group. A predictive model was established based on the proportions of these 3 habitats. Based on the proportion of low-, medium-, and high-enhancement habitats within the tumor, a habitat radiomics model was constructed. After LASSO selection and logistic regression analysis, 3 arterial phase and 3 venous phase radiomic features were selected to build the APRM and VPRM, respectively. Logistic regression analysis identified the following factors for the clinical data model: comorbidities ( OR=0.275, P=0.031), maximum tumor diameter ( OR=1.149, P=0.019), red blood cell count ( OR=0.463, P=0.022), alpha fetoprotein >400 μg/L ( OR=3.452, P=0.017), and tyrosine kinase inhibitor therapy ( OR=3.072, P=0.048). Among the single predictive model′s comparison, the AUC of habitat radiomics model was 0.860 (95% confidence interval(95% CI): 0.789 to 0.932), while those of the APRM、VPRM and clinical data model were 0.850 (95% CI: 0.773 to 0.926), 0.855 (95% CI: 0.782 to 0.928), and 0.774 (95% CI: 0.681 to 0.867), respectively, and there were no statistically significant among these models (all P>0.05). Among the combination models, the AUC of the habitat rediomic-clinical data combination model was 0.881 (95% CI: 0.814 to 0.947); the AUC of arterial phase rediomic-clinical data combination model was 0.897 (95% CI: 0.833 to 0.961); and the AUC of venous phase rediomic-clinical data combination model was 0.888 (95% CI: 0.826 to 0.951), but there were no statistically significant among the 3 models (all P>0.05). The calibration curve showed that the habitat rediomic-clinical data combination model had the most accurate predictive probability. Internal validation showed that the AUC of habitat rediomic-clinical data combination model was 0.848 (95% CI: 0.772 to 0.922), and the predictive performance was better than that of the clinical-data model (0.733 (95% CI: 0.670 to 0.863)). Conclusion:The habitat radiomics model based on enhanced CT can effectively predict early treatment responses to the HAIC combined with targeted therapy or immunotherapy in advanced HCC patients, which provides theoretical basis for individualized treatment in advanced HCC.

Objective:To investigate the effects and underlying mechanism of ionizing radiation on the adipogenic of mesenchymal stem cells(MSCs).Methods:Mouse MSCs were cultured in vitro and treated with 2 Gy and 6 Gy radiation with 60Co,and the radiation dose rate was 0.98 Gy/min.Bulk RNA-seq was performed on control and irradiated MSCs.The changes of adipogenic differentiation and oxidative stress pathways of MSC were revealed by bioinformatics analysis.Oil Red O staining was used to detect the adipogenic differentiation ability of MSCs in vitro,and real-time fluorescence quantitative PCR(qPCR)was used to detect the expression differences of key regulatory factors Cebpa,Lpl and Pparg after radiation treatment.At the same time,qPCR and Western blot were used to detect the effect of inhibition of Nrf2,a key factor of antioxidant stress pathway,on the expression of key regulatory factors of adipogenesis.Moreover,the species conservation of the irradiation response of human bone marrow MSCs and mouse MSC was determined by qPCR.Results:Bulk RNA-seq suggested that ionizing radiation promotes adipogenic differentiation of MSCs and up-regulation of oxidative stress-related genes and pathways.The results of Oil Red O staining and qPCR showed that ionizing radiation promoted the adipogenesis of MSCs,with high expression of Cebpa,Lpl and Pparg,as well as oxidative stress-related gene Nrf2.Nrf2 pathway inhibitors could further enhance the adipogenesis of MSCs in bone marrow after radiation.Notably,the similar regulation of oxidative pathways and enhanced adipogenesis post irradiation were observed in human bone marrow MSCs.In addition,irradiation exposure led to up-regulated mRNA expression of interleukin-6 and down-regulated mRNA expression of colony stimulating factor 2 in human bone marrow MSCs.Conclusion:Ionizing radiation promotes adipogenesis of MSCs in mice,and oxidative stress pathway participates in this effect,blocking Nrf2 further promotes the adipogenesis of MSCs.Additionally,irradiation activates oxidative pathways and promotes adipogenic differentiation of human bone marrow MSCs.

Objective:To establish an in vitro cell model simulating acute graft-versus-host disease(aGVHD)bone marrow microenvironment injury with the advantage of mouse serum of aGVHD model and explore the effect of serum of aGVHD mouse on the adipogenic differentiation ability of mesenchymal stem cells(MSCs).Methods:The 6-8-week-old C57BL/6N female mice and BALB/c female mice were used as the donor and recipient mice of the aGVHD model,respectively.Bone marrow transplantation(BMT)mouse model(n=20)was established by being injected with bone marrow cells(1 × 10'per mouse)from donor mice within 4-6 hours after receiving a lethal dose(8.0 Gy,72.76 cGy/min)of y ray general irradiation.A mouse model of aGVHD(n=20)was established by infusing a total of 0.4 ml of a mixture of donor mouse-derived bone marrow cells(1 × 107 per mouse)and spleen lymphocytes(2 × 106 per mouse).The blood was removed from the eyeballs and the mouse serum was aspirated on the 7th day after modeling.Bone marrow-derived MSCs were isolated from 1-week-old C57BL/6N male mice and incubated with 2％,5％and 10％BMT mouse serum and aGVHD mouse serum in the medium,respectively.The effect of serum in the two groups on the in vitro adipogenic differentiation ability of mouse MSCs was detected by Oil Red O staining.The expression levels of related proteins PPARy and CEBPα were detected by Western blot.The expression differences of key adipogenic transcription factors including PPARy,CEBPα,FABP4 and LPL were determined by real-time quantitative PCR(RT-qPCR).Results:An in vitro cell model simulating the damage of bone marrow microenvironment in mice with aGVHD was successfully established.Oil Red O staining showed that the number of orange-red fatty droplets was significantly reduced and the adipogenic differentiation ability of MSC was impaired at aGVHD serum concentration of 10％compared with BMT serum.Western blot experiments showed that adipogenesis-related proteins PPARy and CEBPα expressed in MSCs were down-regulated.Further RT-qPCR assay showed that the production of PPARy,CEBPα,FABP4 and LPL,the key transcription factors for adipogenic differentiation of MSC,were significantly reduced.Conclusion:The adipogenic differentiation capacity of MSCs is inhibited by aGVHD mouse serum.

Objective:To analyze the influence of forming direction on the surface characteristics,elastic modulus,bending strength and fracture toughness of printed parts and the relationship between forming direction and force direction,and to provide scientific basis and guidance for the clinical applica-tion of oral denture base resin materials.Methods:The 3D printing technology was used to print denture base resin samples.The shape and size of the samples referred to the current standard for testing conven-tional denture base materials.The samples used for physical performance testing were cylindrical(with a diameter of 15 mm and a thickness of 1 mm)and printed at different angles along the Z axis(0°,45°,90°).Scanning electron microscope was used to observe the microscopic topography of the different sam-ples.The color stability of different samples was observed by color stabilizer.The surface roughness of the samples was analyzed by using surface roughness tester.The Vickers hardness was measured to ana-lyze the hardness of the samples.The samples used for mechanical performance testing were rectangular(elastic modulus and bending strength:A length of 64 mm,a width of 10 mm,and a height of 3.3 mm;fracture toughness:A length of 39 mm,a width of 8 mm,and a height of 4 mm),divided into two groups:W group and H group.The W group was printed from the bottom up along the Z axis with the length × width as the bottom surface parallel to the X,Y axis plane,while the H group printed from the bottom up along the Z axis with the length × height as the bottom surface parallel to the X,Y axis plane.The forming angles of both groups were equally divided into 0°,45°,and 90°.The elastic modulus,bending strength and fracture toughness of different samples were studied through universal mechanical testing machine.SPSS 22.0 software was used for statistical analysis.Results:The microscopic topogra-phy and roughness of different samples were closely related to the printing direction,with significant differences between the 0°,45°,and 90° specimens.The 0° specimens had the smoothest surface(roughness＜1 μm).The surface of the 45 ° specimen was the roughest(roughness＞3 μm).The microhardness of the 0° sample was the best[(196.13±0.20)MPa],with a significant difference com-pared with the 90° sample[(186.62±4.81)MPa,P＜0.05].The mechanical properties of different samples were also closely related to the printing direction.The elastic modulus,bending strength,and fracture toughness of the 45° samples in the W group were the highest compared with the other groups.The results of elastic modulus showed that in the H group,the 45° specimens had the highest elastic mo-dulus,which was significantly different from the 0° and 90° specimens(P＜0.05).The elastic modulus of 0° and 45° specimens in the W group were higher than those in 90° specimens(P＜0.05).The bending strength results showed that there was no significant difference between the specimens from dif-ferent angles in the H group.The bending strength of the 90° specimens in the W group was the smallest,and there was a significant difference between 90° and the 0° and 45° specimens(P＜0.05);And the bendind strength of the 0° and 45° specimens in the W group was significantly higher than that of the 0° and 45° specimens in the H group(P＜0.05).The fracture toughness results showed that the fracture toughness of the H group specimens was lower than 1.9 MPa m1/2,which was specified in the denture base standard.The 45° samples in the W group were the highest,with significant differences compared with the 0° and 90° samples(P＜0.05).And the 90° samples of the W group specimens were lower than 1.9 MPa m1/2.And the fracture toughness of the 45° specimen in the W group was significantly higher than that of all the specimens in the H group(P＜0.05).Conclusion:The 0° samples had rela-tively better physical properties.The 45° samples had the best mechanical properties.But the fracture toughness of specimens(H group and 90° samples of W group)did not yet meet clinical requirements.That indicated that the characteristics of the 3D printing denture base resin were affected by the printing direction.Only when the performance of the printed samples in all directions met the minimum require-ments of the standard,they could be used in clinical practice.