1.Improve effects of aromatase inhibitors on the height of children with short stature
Mengmeng XIA ; Jinbo XIANG ; Jun LUO ; Xiaoxia ZHU
China Pharmacy 2025;36(4):501-506
The primary approach for clinical treatment of short stature (SS) in children is the use of recombinant human growth hormone (rhGH). However, the high cost of treatment and the daily injection frequency place a significant economic and psychological burden on the families of affected children. For SS adolescents who have missed the peak growth velocity period of puberty, the use of rhGH alone is also difficult to significantly increase their final adult height. Numerous studies have shown that aromatase inhibitors (AIs) are effective in improving the height of SS boys, especially the combination therapy of AIs and rhGH, which has a better effect. Although the use of AIs may affect the children’s bones, cognitive function, reproductive system and hormone levels, most of these effects are temporary. Since existing research has not fully elucidated its impact on the pubertal changes of girls, it is necessary to fully weigh the benefits and risks when using AIs to treat SS girls in clinical practice. In the future, it is also necessary to carry out pharmacoeconomic research based on the medical environment of China to evaluate the cost- effectiveness of AIs for SS in children.
2.Clinical practice guidelines for intraoperative cell salvage in patients with malignant tumors
Changtai ZHU ; Ling LI ; Zhiqiang LI ; Xinjian WAN ; Shiyao CHEN ; Jian PAN ; Yi ZHANG ; Xiang REN ; Kun HAN ; Feng ZOU ; Aiqing WEN ; Ruiming RONG ; Rong XIA ; Baohua QIAN ; Xin MA
Chinese Journal of Blood Transfusion 2025;38(2):149-167
Intraoperative cell salvage (IOCS) has been widely applied as an important blood conservation measure in surgical operations. However, there is currently a lack of clinical practice guidelines for the implementation of IOCS in patients with malignant tumors. This report aims to provide clinicians with recommendations on the use of IOCS in patients with malignant tumors based on the review and assessment of the existed evidence. Data were derived from databases such as PubMed, Embase, the Cochrane Library and Wanfang. The guideline development team formulated recommendations based on the quality of evidence, balance of benefits and harms, patient preferences, and health economic assessments. This study constructed seven major clinical questions. The main conclusions of this guideline are as follows: 1) Compared with no perioperative allogeneic blood transfusion (NPABT), perioperative allogeneic blood transfusion (PABT) leads to a more unfavorable prognosis in cancer patients (Recommended); 2) Compared with the transfusion of allogeneic blood or no transfusion, IOCS does not lead to a more unfavorable prognosis in cancer patients (Recommended); 3) The implementation of IOCS in cancer patients is economically feasible (Recommended); 4) Leukocyte depletion filters (LDF) should be used when implementing IOCS in cancer patients (Strongly Recommended); 5) Irradiation treatment of autologous blood to be reinfused can be used when implementing IOCS in cancer patients (Recommended); 6) A careful assessment of the condition of cancer patients (meeting indications and excluding contraindications) should be conducted before implementing IOCS (Strongly Recommended); 7) Informed consent from cancer patients should be obtained when implementing IOCS, with a thorough pre-assessment of the patient's condition and the likelihood of blood loss, adherence to standardized internally audited management procedures, meeting corresponding conditions, and obtaining corresponding qualifications (Recommended). In brief, current evidence indicates that IOCS can be implemented for some malignant tumor patients who need allogeneic blood transfusion after physician full evaluation, and LDF or irradiation should be used during the implementation process.
3.Resveratrol activates extracellular-regulated protein kinase 5 signaling protein to promote proliferation of mouse MC3T3-E1 cells
Yongkang NIU ; Zhiwei FENG ; Yaobin WANG ; Zhongcheng LIU ; Dejian XIANG ; Xiaoyuan LIANG ; Zhi YI ; Hongwei ZHAN ; Bin GENG ; Yayi XIA
Chinese Journal of Tissue Engineering Research 2025;29(5):908-916
BACKGROUND:The extracellular-regulated protein kinase 5(ERK5)signaling protein is essential for the survival of organisms,and resveratrol can promote osteoblast proliferation through various pathways.However,whether resveratrol can regulate osteoblast function through the ERK5 signaling protein needs further verification. OBJECTIVE:To explore the regulatory effect of ERK5 on the proliferation of MC3T3-E1 cells and related secreted proteins,and to further verify whether resveratrol can complete the above process by activating ERK5. METHODS:Mouse MC3T3-E1 preosteoblasts were treated with complete culture medium,XMD8-92(an ERK5 inhibitor),epidermal growth factor(an ERK5 activator),resveratrol alone,XMD8-92+EGF,and resveratrol+XMD8-92,respectively.Western blot assay was used to detect the expression of ERK5 and p-ERK5 proteins,proliferation-related proteins Cyclin D1,CDK4 and PCNA,and osteoblast-secreted proteins osteoprotegerin and receptor activator of nuclear factor-κB ligand in MC3T3-E1 cells of each group.The fluorescence intensity of ERK5,osteoprotegerin and receptor activator of nuclear factor-κB ligand in each group was detected by cell immunofluorescence staining,and cell proliferation was detected by EdU staining,respectively.The appropriate concentration and time of resveratrol intervention in MC3T3-E1 cells were determined by cell morphology observation and cell counting kit-8 assay. RESULTS AND CONCLUSION:The activation of ERK5 signaling protein could effectively promote the proliferation of MC3T3-E1 cells,up-regulate the osteoprotegerin/receptor activator of nuclear factor-κB ligand ratio.The appropriate concentration and time for resveratrol intervention in MC3T3-E1 cells was 5 μmol/L and 24 hours,respectively.Resveratrol could activate ERK5 signaling protein,thereby promoting osteoblast proliferation and up-regulating the osteoprotegerin/RANKL ratio.All these results indicate that resveratrol can promote the proliferation of MC3T3-E1 cells and up-regulate the osteoprotegerin/RANKL ratio by activating the ERK5 signaling protein.
4.Mechanisms by which microgravity causes osteoporosis
Dejian XIANG ; Xiaoyuan LIANG ; Shenghong WANG ; Changshun CHEN ; Cong TIAN ; Zhenxing YAN ; Bin GENG ; Yayi XIA
Chinese Journal of Tissue Engineering Research 2025;29(10):2132-2140
BACKGROUND:The imbalance between bone resorption and bone formation in microgravity environments leads to significant bone loss in astronauts.Current research indicates that bone loss under microgravity conditions is the result of the combined effects of various cells,tissues,and systems. OBJECTIVE:To review different biological effects of microgravity on various cells,tissues,or systems,and summarize the mechanisms by which microgravity leads to the development of osteoporosis. METHODS:Databases such as PubMed,Web of Science,and the Cochrane Database were searched for relevant literature from 2000 to 2023.The inclusion criteria were all articles related to tissue engineering studies and basic research on osteoporosis caused by microgravity.Ultimately,85 articles were included for review. RESULTS AND CONCLUSION:(1)In microgravity environment,bone marrow mesenchymal stem cells tend to differentiate more into adipocytes rather than osteoblasts,and hematopoietic stem cells in this environment are more inclined to differentiate into osteoclasts,reducing differentiation into the erythroid lineage.At the same time,microgravity inhibits the proliferation and differentiation of osteoblasts,promotes apoptosis of osteoblasts,alters cell morphology,and reduces the mineralization capacity of osteoblasts.Microgravity significantly increases the number and activity of osteoclasts.Microgravity also hinders the differentiation of osteoblasts into osteocytes and promotes the apoptosis of osteocytes.(2)In a microgravity environment,the body experiences changes such as skeletal muscle atrophy,microvascular remodeling,bone microcirculation disorders,and endocrine disruption.These changes lead to mechanical unloading in the bone microenvironment,insufficient blood perfusion,and calcium cycle disorders,which significantly impact the development of osteoporosis.(3)At present,the mechanism by which microgravity causes osteoporosis is relatively complex.A deeper study of these physiological mechanisms is crucial to ensuring the health of astronauts during long-term space missions,and provides a theoretical basis for the prevention and treatment of osteoporosis.
5.Exploration on Mechanism of Topical Treatment of Allergic Contact Dermatitis in Mice with Portulacae Herba Based on Nrf2/HO-1/NF-κB Signaling Pathway
Xiaoxue WANG ; Guanwei FAN ; Xiang PU ; Zhongzhao ZHANG ; Xia CHEN ; Ying TANG ; Nana WU ; Jiangli LUO ; Xiangyan KONG
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(3):115-123
ObjectiveTo investigate the mechanism of topical treatment of allergic contact dermatitis (ACD) mice with Portulacae Herba based on the nuclear factor E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1)/nuclear factor-κB (NF-κB) signaling pathway. MethodsA total of 70 6-week-old specific pathogen free (SPF) female Kunming mice were adaptively fed for 1 week and randomly divided into blank group, model group, compound dexamethasone acetate cream group (2.075×10-2 g·g-1), blank matrix cream group, low-dose Portulacae Herba cream group (0.1 g·g-1), high-dose Portulacae Herba cream group (0.2 g·g-1), and Portulacae Herba + inhibitor group (0.2 g·g-1 + 30 mg·kg-1 ML385), with 10 mice in each group. One day before the experiment, the mice were shaved on the neck and back. Except for the blank group, the mice in the other groups were treated with 2,4-dinitrochlorobenzene (DNCB) to establish an ACD model. After respective administration, the skin lesion of the mice was scored, and the histopathological changes of the skin were stained with hematoxylin-eosin (HE). Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of interleukin-6 (IL-6), interleukin-1β (IL-1β), reactive oxygen species (ROS), superoxide dismutase (SOD) activity, and malondialdehyde (MDA) in serum of mice. The expression of Nrf2/HO-1/NF-κB signaling pathway-related proteins in mouse skin tissue was detected by immunohistochemistry (IHC), Western blot, and real-time fluorescence quantitative polymerase chain reaction (Real-time PCR). ResultsCompared with the blank group, the mice in the model group had an increased skin lesion score (P<0.01), severe pathological damage to skin tissue, increased content of IL-1β, IL-6, ROS, and MDA in their serum (P<0.01), and decreased content of SOD (P<0.01). In addition, the mRNA and protein expression levels of Nrf2, HO-1, and nuclear factor-κB inhibitor α (IκBα) in skin tissue were up-regulated (P<0.01), while the protein expression levels of phosphorylated (p)-IκBα and p-NF-κB p65 and the mRNA expression of NF-κB p65 were down-regulated (P<0.01). Compared with the model group and the blank matrix cream group, the mice treated with Portulacae Herba had a decreased skin lesion score (P<0.01), reduced pathological damage to skin tissue, decreased content of IL-1β, IL-6, ROS, and MDA in their serum (P<0.01), and increased content of SOD (P<0.01). Additionally, the mRNA and protein expression levels of Nrf2, HO-1, and IκBα in skin tissue were down-regulated (P<0.05,P<0.01), and the protein expression levels of p-IκBα and p-NF-κB p65 and the mRNA expression of NF-κB p65 were up-regulated (P<0.05,P<0.01). Compared with the Portulacae Herba + inhibitor group, the high-dose Portulacae Herba cream group had a decreased skin lesion score (P<0.01), alleviated pathological damage to skin tissue, decreased content of IL-1β, IL-6, ROS, and MDA in the serum of mice (P<0.05,P<0.01), and increased content of SOD (P<0.01). The protein expression levels of Nrf2, HO-1, and IκBα and the mRNA expression of Nrf2 and HO-1 in skin tissue were up-regulated (P<0.05,P<0.01), and the protein expression levels of p-IκBα and p-NF-κB p65 and the mRNA expression of NF-κB p65 were down-regulated (P<0.05). ConclusionPortulacae Herba can improve DNCB-induced ACD skin damage in mice by regulating the Nrf2/HO-1/NF-κB signaling pathway.
6.Effects of Portulaca oleracea cream on skin pruritus and barrier function in allergic contact dermatitis mice
Xiaoxue WANG ; Xia CHEN ; Xiang PU ; Guanwei FAN ; Xiangyan KONG ; Ying TANG ; Nana WU ; Jiangli LUO
China Pharmacy 2025;36(11):1352-1357
OBJECTIVE To study the effects and mechanism of Portulaca oleracea cream on skin pruritus and barrier function in allergic contact dermatitis (ACD) mice. METHODS Low-concentration and high-concentration P. oleracea creams were prepared, with the P. oleracea extract solution (1 g/mL, calculated by crude drug) concentrations of 10% and 20%. Sixty BALB/c mice were randomly allocated into blank group, model group, Mometasone furoate cream group (positive control), blank matrix cream group, P. oleracea low-concentration and high-concentration cream groups. Except for blank group, ACD model was induced in each group using 2,4-dinitrochlorobenzene solution. The blank group and model groups received normal saline, while the remaining groups were treated with their respective creams, once a day, at a dose of approximately 0.5 g per application, continuously for 14 days. At 24 h post-final administration, skin lesions of mice were observed and scored; pathological changes of skin tissue were observed; serum levels of immunoglobulin E(IgE) and tumor necrosis factor-α (TNF-α) were quantified. mRNA expression of MAS-related G protein-coupled receptors (including MrgprA3, MrgprC11, and MrgprD) in dorsal root ganglion (DRG) was assessed; while protein expressions of skin barrier function-related proteins Claudin-1 and Occludin in skin tissues were determined. RESULTS Compared with blank group, mice in the model group exhibited severe skin damage, characterized by loss of epidermal architecture, hyperkeratosis of the skin tissue, and the infiltration of a large number of inflammatory cells. The skin injury scores, as well as the serum levels of IgE and TNF-α, and the mRNA expression levels of MrgprA3, MrgprC11, and MrgprD in DRG, were all significantly elevated compared to the blank group (P<0.05 or P<0.01); in contrast, the protein expression levels of Claudin-1 and Occludin in the skin tissue were markedly reduced (P<0.05). Compared with model group, mice in P. oleracea low-concentration and high- concentration cream groups demonstrated significant alleviation of skin damage, as evidenced by reduced epidermal hyperplasia, mitigated spongiosis in the dermis, and decreased infiltration of inflammatory cells; these quantitative indicators were almost significantly reversed (P<0.05 or P<0.01). No significant differences were observed in the aforementioned skin injuries, pathological alterations, or quantitative indicators between the blank matrix cream group and the model group. CONCLUSIONS P. oleracea may ameliorate skin lesions and restore skin barrier function of ACD mice, the mechanism of which may be associated with downregulating mRNA expressions of MrgprA3, MrgprC11 and MrgprD in DRG, and up-regulating the protein expressions of Claudin-1 and Occludin in skin tissue.
7.Construction and effectiveness analysis of working model of cough and asthma pharmaceutical care clinic
Xiang LI ; Ying LI ; Yongzhong WANG ; Lunzhu XIA
China Pharmacy 2025;36(15):1910-1914
OBJECTIVE To establish a working model for the cough and asthma pharmaceutical care clinic and analyze the effects of outpatient pharmaceutical care interventions on patients. METHODS A pharmaceutical care clinic for cough and asthma was established in our hospital, with comprehensive regulations and rules, complete infrastructure and defined pharmaceutical care workflows. The demographic data of patients (gender, age, residence, disease duration and so on) were collected from May 2021 to December 2024. Indicators including health status, disease severity, inhalation technique, and medication adherence during visits and follow-up were collected and analyzed statistically, to assess the effects of pharmaceutical care interventions on patients. RESULTS The service procedure for the cough and asthma pharmaceutical care clinic in our hospital was established. A total of 215 patients’ basic information was collected. It was found that among the patients, males accounted for 55.35%, with an average age of (60.91±15.75) years old. Patients aged 60 to 69 constituted the largest proportion at 28.37%, and they exhibited relatively poor medication adherence [with an average score of (5.64±1.76)]. The majority of patients were diagnosed with chronic obstructive pulmonary disease (COPD) and prescribed budesonide/formoterol powder inhalers. In 68 follow-up cases, EQ-5D-5L scores increased by 5.81 points (P<0.05); COPD Assessment Test (CAT) scores decreased by 4.05 points (P<0.05), indicating reduced disease burden. Asthma Control Test (ACT) scores improved by 4.80 points, reaching partial control levels. Inhaler technique scores increased by 2.31 points (P<0.05). Medication adherence scores rose by 1.09 points (P<0.05). Patient satisfaction was over 90%. CONCLUSIONS After pharmaceutical care intervention, patients’ health status, disease severity, inhalant use technique, and compliance have all improved, and their satisfaction with the cough and asthma pharmaceutical care outpatient service is high. The pharmaceutical care intervention provided by the cough and asthma pharmaceutical care outpatient service can improve patients’ disease symptoms and medication compliance, and enhance the level of safe and rational drug use in the hospital.
8.The Role of AMPK in Diabetic Cardiomyopathy and Related Intervention Strategies
Fang-Lian LIAO ; Xiao-Feng CHEN ; Han-Yi XIANG ; Zhi XIA ; Hua-Yu SHANG
Progress in Biochemistry and Biophysics 2025;52(10):2550-2567
Diabetic cardiomyopathy is a distinct form of cardiomyopathy that can lead to heart failure, arrhythmias, cardiogenic shock, and sudden death. It has become a major cause of mortality in diabetic patients. The pathogenesis of diabetic cardiomyopathy is complex, involving increased oxidative stress, activation of inflammatory responses, disturbances in glucose and lipid metabolism, accumulation of advanced glycation end products (AGEs), abnormal autophagy and apoptosis, insulin resistance, and impaired intracellular Ca2+ homeostasis. Recent studies have shown that adenosine monophosphate-activated protein kinase (AMPK) plays a crucial protective role by lowering blood glucose levels, promoting lipolysis, inhibiting lipid synthesis, and exerting antioxidant, anti-inflammatory, anti-apoptotic, and anti-ferroptotic effects. It also enhances autophagy, thereby alleviating myocardial injury under hyperglycemic conditions. Consequently, AMPK is considered a key protective factor in diabetic cardiomyopathy. As part of diabetes prevention and treatment strategies, both pharmacological and exercise interventions have been shown to mitigate diabetic cardiomyopathy by modulating the AMPK signaling pathway. However, the precise regulatory mechanisms, optimal intervention strategies, and clinical translation require further investigation. This review summarizes the role of AMPK in the prevention and treatment of diabetic cardiomyopathy through drug and/or exercise interventions, aiming to provide a reference for the development and application of AMPK-targeted therapies. First, several classical AMPK activators (e.g., AICAR, A-769662, O-304, and metformin) have been shown to enhance autophagy and glucose uptake while inhibiting oxidative stress and inflammatory responses by increasing the phosphorylation of AMPK and its downstream target, mammalian target of rapamycin (mTOR), and/or by upregulating the gene expression of glucose transporters GLUT1 and GLUT4. Second, many antidiabetic agents (e.g., teneligliptin, liraglutide, exenatide, semaglutide, canagliflozin, dapagliflozin, and empagliflozin) can promote autophagy, reverse excessive apoptosis and autophagy, and alleviate oxidative stress and inflammation by enhancing AMPK phosphorylation and its downstream targets, such as mTOR, or by increasing the expression of silent information regulator 1 (SIRT1) and peroxisome proliferator-activated receptor‑α (PPAR‑α). Third, certain anti-anginal (e.g., trimetazidine, nicorandil), anti-asthmatic (e.g., farrerol), antibacterial (e.g., sodium houttuyfonate), and antibiotic (e.g., minocycline) agents have been shown to promote autophagy/mitophagy, mitochondrial biogenesis, and inhibit oxidative stress and lipid accumulation via AMPK phosphorylation and its downstream targets such as protein kinase B (PKB/AKT) and/or PPAR‑α. Fourth, natural compounds (e.g., dihydromyricetin, quercetin, resveratrol, berberine, platycodin D, asiaticoside, cinnamaldehyde, and icariin) can upregulate AMPK phosphorylation and downstream targets such as AKT, mTOR, and/or the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), thereby exerting anti-inflammatory, anti-apoptotic, anti-pyroptotic, antioxidant, and pro-autophagic effects. Fifth, moderate exercise (e.g., continuous or intermittent aerobic exercise, aerobic combined with resistance training, or high-intensity interval training) can activate AMPK and its downstream targets (e.g., acetyl-CoA carboxylase (ACC), GLUT4, PPARγ coactivator-1α (PGC-1α), PPAR-α, and forkhead box protein O3 (FOXO3)) to promote fatty acid oxidation and glucose uptake, and to inhibit oxidative stress and excessive mitochondrial fission. Finally, the combination of liraglutide and aerobic interval training has been shown to activate the AMPK/FOXO1 pathway, thereby reducing excessive myocardial fatty acid uptake and oxidation. This combination therapy offers superior improvement in cardiac dysfunction, myocardial hypertrophy, and fibrosis in diabetic conditions compared to liraglutide or exercise alone.
9. Effect of miR-141-5p/ZNF705A on adhesion of bone marrow mesenchymal stem cells in chronic myeloid leukemia cell-derived exosomes
Jing BAO ; Han XU ; Wan-Jie WANG ; Ting-Ting XU ; Ji-Fei DAI ; Rui-Xiang XIA
Chinese Pharmacological Bulletin 2024;40(3):506-514
Aim To investigate the effect of miR-141-5p/ZNF705A in chronic myeloid leukemia(CML)cell-derived exosome(Exo)on the adhesion of bone marrow mesenchymal stem cells(BMSCs). Methods The morphology and size of Exo in peripheral blood from CML patients and K562 cells were examined by electron microscopy and NTA particle size analysis. The expressions of Exo and BMSCs marker molecules and adhesion proteins in K562 cells were detected by qRT-PCR and Western blot before and after transfection. The adhesion ability of BMSCs was detected by cell adhesion assay, and the cellular activity of BMSCs was examined using CCK-8. miR-141-5p binding to ZNF705A was detected by luciferase assay. Results qRT-PCR results showed that miR-141-5p expression was significantly reduced in both CML patients and K562 cell-derived Exo. qRT-PCR, Western blot and other results showed that BMSCs in CML patients had significantly reduced the expression of adhesion proteins CD44 and CXCL12, and were able to phagocytose K562 cell-derived Exo. Further, K562-derived Exo was found to reduce CD44 and CXCL12 expression and adhesion in Exo-promoted BMSCs compared with CD34+ cells. Meanwhile, the results of dual luciferase reporter assay verified that miR-141-5p targeted binding to ZNF705A. Finally, we found ZNF705A could be targeted by up-regulating miR-141-5p expression in Exo of K562 cells, which in turn inhibited the adhesion of BMSCs. Conclusions K562 cells down-regulate miR-141-5p expression in Exo and inhibit the adhesion function of BMSCs by targeting ZNF705A, thus regulating the bone marrow hematopoietic function in CML patients.
10.Effect of printing orientation on physical and mechanical properties of 3D printing prosthodontic base resin materials
Xinxin ZHAN ; Lulu CAO ; Dong XIANG ; Hao TANG ; Dandan XIA ; Hong LIN
Journal of Peking University(Health Sciences) 2024;56(2):345-351
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.

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