Direct antiglobulin test (DAT), also known as Coomb's test, is a method used in blood immunology to detect whether the surface of red blood cells is sensitized by immunoglobulin or complement. It is mainly used in the diagnosis of autoimmune hemolytic anemia (AIHA), neonatal hemolytic anemia, hemolytic transfusion reaction and blood matching during blood transfusion. DAT positive has always been the focus of researchers, because it has an important impact on the efficacy of blood transfusion. In recent years, there has been extensive research on the identification of DAT positivity types and the distribution characteristics of diseases in clinical patients, and the study on hemolytic disease of the newborn has also been popular. However, the transfusion safety of DAT-positive blood donors has been a hot topic in the field of blood transfusion for many years. Moreover, there is no clear requirement from the state on the handling of DAT-positive blood and whether DAT-positive blood donors should be deferred from donation. Therefore, this article reviews the serological studies on DAT immunotyping and IgG subtype typing of voluntary blood donors, as well as the impact of DAT-positive blood on blood transfusion safety, in order to provide references for the blood issuance strategy of DAT-positive blood and whether DAT-positive blood donors should be deferred.

Cluster of differentiation 36 (CD36) is a highly glycosylated double transmembrane glycoprotein, which is involved in the inflammatory response and immune regulation of the body. It plays a key role in mediating the mechanism of immune-related blood transfusion reactions and regulating the function of immune cells. It has an important impact on blood transfusion safety and has become a current research hotspot. This article reviews and comprehensively analyzes the research progress of the specific role of CD36 in the immune response of blood transfusion and its regulatory mechanism at home and abroad. Combined with clinical cases and experimental data, the pathophysiological mechanism of CD36 in immune response and its immune-mediated blood transfusion safety issues are reviewed. It is expected to provide new theoretical support and practical guidance for the field of blood transfusion safety and promote the further development of blood transfusion medicine.

OBJECTIVE: To describe a novel arthroscopic technique of modified tri-anchor double-pulley suture-bridge in repairing medium-sized supraspinatus tendon tears and evaluate the early effectiveness. METHODS: Between June 2021 and January 2024, 26 patients with medium-sized supraspinatus tendon tears who underwent arthroscopic modified tri-anchor double-pulley suture-bridge repair and met the selective criteria were included. There were 11 males and 15 females with an average age of 61.4 years (range, 43-74 years). Five patients had a significant history of trauma, while the remaining 21 patients had no apparent cause. The time from symptom onset to hospitalization was 3-25 months (mean, 7.9 months). The effectiveness was evaluated during follow-up, including the scores of University of California at Los Angeles (UCLA), American Shoulder and Elbow Surgeons (ASES), visual analogue scale (VAS), the range of forward flexion, abduction, external rotation, and internal rotation, and patient's satisfaction. Either MRI or ultrasound examination were used to evaluate structural integrity of the tendon. RESULTS: The operation time was 65-110 minutes (mean, 81.8 minutes). All patients were followed up 12-43 months (mean, 23.0 months). At 3 and 12 months after operation, the shoulder range of flexion, abduction, external rotation, and internal rotation, and the scores of VAS, UCLA, and ASES significantly improved when compared with those before operation ( P<0.05). The improvement was further observed at 12 months compared to 3 months ( P<0.05). At last follow-up, 13 patients were very satisfied with the effectiveness, 11 patients were satisfied, 1 was relatively satisfied, and 1 was dissatisfied. During follow-up, 15 patients underwent imaging examination and imaging reexamination showed that the re-tear rate of tendon was 6.6%(1/15). The remaining 11 patients refused imaging examination. Complications included partial anchor withdrawal in 1 case, shoulder stiffness in 5 cases, and mild pain in shoulder joint in 2 cases in physical activity or heavy physical activity. CONCLUSION Arthroscopic modified tri-anchor double-pulley suture-bridge technique is a novel surgical technique that uses double-loaded suture anchors as medial- and lateral-row anchors. In repairing medium-sized supraspinatus tendon tears, 6 sets of double-pulley suture-bridges can be created from one medial-row anchor; knotless medial-row can reduce re-tear rate of the tendon; good early effectiveness is obtained.
Humans ; Female ; Male ; Middle Aged ; Arthroscopy/methods* ; Adult ; Rotator Cuff Injuries/surgery* ; Aged ; Suture Techniques ; Treatment Outcome ; Suture Anchors ; Rotator Cuff/surgery* ; Range of Motion, Articular ; Tendon Injuries/surgery* ; Patient Satisfaction

OBJECTIVES: Neuropathic pain (NP) is one of the most common forms of chronic pain, yet current treatment options are limited in effectiveness. Peripheral nerve injury activates spinal microglia, altering their inflammatory response and phagocytic functions, which contributes to the progression of NP. Most current research on NP focuses on microglial inflammation, with relatively little attention to their phagocytic function. Early growth response factor 2 (EGR2) has been shown to regulate microglial phagocytosis, but its specific role in NP remains unclear. This study aims to investigate how EGR2 modulates microglial phagocytosis and its involvement in NP, with the goal of identifying potential therapeutic targets. METHODS: Adult male Sprague-Dawley (SD) rats were used to establish a chronic constriction injury (CCI) model of the sciatic nerve. Pain behaviors were assessed on days 1, 3, 7, 10, and 14 post-surgery to confirm successful model induction. The temporal and spatial expression of EGR2 in the spinal cord was examined using real-time quantitative PCR (RT-qPCR), Western blotting, and immunofluorescence staining. Adeno-associated virus (AAV) was used to overexpress EGR2 in the spinal cord, and behavioral assessments were performed to evaluate the effects of EGR2 modulation of NP. CCI and lipopolysaccharide (LPS) models were established in animals and microglial cell lines, respectively, and changes in phagocytic activity were measured using RT-qPCR and fluorescent latex bead uptake assays. After confirming the involvement of microglial phagocytosis in NP, AAV was used to overexpress EGR2 in both in vivo and in vitro models, and phagocytic activity was further evaluated. Finally, eukaryotic transcriptome sequencing was conducted to screen differentially expressed mRNAs, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses to identify potential downstream effectors of EGR2. RESULTS: The CCI model successfully induced NP. Following CCI, EGR2 expression in the spinal cord was upregulated in parallel with NP development. Overexpression of EGR2 via spinal AAV injection enhanced microglial phagocytic activity and increased pain hypersensitivity in rats. Both animal and cellular models showed that CCI or LPS stimulation enhanced microglial phagocytosis, which was further amplified by EGR2 overexpression. Transcriptomic analysis of spinal cord tissues from CCI rats overexpressing EGR2 revealed upregulation of numerous genes associated with microglial phagocytosis and pain regulation. Among them, Lag3 emerged as a potential downstream target of EGR2. CONCLUSIONS EGR2 contributes to the maintenance of NP by enhancing microglial phagocytosis in the spinal dorsal horn.
Animals ; Microglia/metabolism* ; Phagocytosis/physiology* ; Rats, Sprague-Dawley ; Neuralgia/physiopathology* ; Early Growth Response Protein 2/metabolism* ; Male ; Rats ; Spinal Cord/metabolism* ; Sciatic Nerve/injuries*

OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is a major health concern in northwest China; however, the impact of particulate matter (PM) exposure during sand-dust storms (SDS) remains poorly understood. Therefore, this study aimed to investigate the association between PM exposure on SDS days and COPD hospitalization risk in arid regions. METHODS: Data on daily COPD hospitalizations were collected from 323 hospitals from 2018 to 2022, along with the corresponding air pollutant and meteorological data for each city in Gansu Province. Employing a space-time-stratified case-crossover design and conditional Poisson regression, we analyzed 265,379 COPD hospitalizations. RESULTS: PM exposure during SDS days significantly increased COPD hospitalization risk [relative risk ( RR) for PM _2.5, lag 3:1.028, 95% confidence interval ( CI): 1.021-1.034], particularly among men and the elderly, and during the cold season. The burden of PM exposure on COPD hospitalization was substantially high in Northwest China, especially in the arid and semi-arid regions. CONCLUSION Our findings revealed a positive correlation between PM exposure during SDS episodes and elevated hospitalization rates for COPD in arid and semi-arid zones in China. This highlights the urgency of developing region-specific public health strategies to address adverse respiratory outcomes associated with SDS-related air quality deterioration.
Humans ; China/epidemiology* ; Pulmonary Disease, Chronic Obstructive/chemically induced* ; Particulate Matter/analysis* ; Hospitalization/statistics & numerical data* ; Male ; Female ; Middle Aged ; Aged ; Air Pollutants/analysis* ; Environmental Exposure/adverse effects* ; Spatio-Temporal Analysis ; Adult ; Sand ; Air Pollution

Objective:To discuss the effect of long non-coding RNA(lncRNA)DUXAP8 in exosomes(Exo)derived from the lung cancer A549 cells on the growth and immune escape of the lung cancer cells,and to clarify the mechanism.Methods:The human lung cancer cell line A549 was cultured,and its exosomes were extracted and identified.The A549 cells were treated with PKH67-labeled Exo to observe the uptake of Exo by A549 cells.Real-time fluorescence quantitative PCR(RT-qPCR)method was used to detect the expression level of lncRNA DUXAP8 in A549 cells before and after Exo treatment.The A549 cells were divided into control group(no treatment),Exo group(A549 cells treated with Exo),Exo+sh-NC group(A549 cells treated with Exo and then transfected with sh-NC),and Exo+sh-DUXAP8 group(A549 cells treated with Exo and then transfected with sh-DUXAP8).RT-qPCR method was used to detect the expression level of lncRNA DUXAP8 in A549 cells in various groups;colony formation assay was used to detect the colony formation abilities of the A549 cells in various groups;5-ethynyl-2'-deoxyuridine(EdU)staining method was used to detect the proliferation abilities of the A549 cells in various groups.After co-culturing A549 cells in various groups with human peripheral blood lymphocytes,flow cytometry was used to detect the percentages of activated CD8+T lymphocytes in the human peripheral blood lymphocytes in various groups;3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)method was used to detect the killing rates of human peripheral blood lymphocytes on the A549 cells in various groups.Results:The diameter of Exo vesicles was 50-150 nm,and the exosome-specific marker proteins cluster of differentiation 63(CD63),cluster of differentiation 9(CD9),tumor susceptibility gene 101(TSG101),and heat shock protein 70(HSP70)were positively expressed,indicating successful exosome extraction.A549 cells efficiently took up PKH67-labeled Exo.The RT-PCR results showed that compared with A549 cells cultured alone,the expression level of lncRNA DUXAP8 in the A549 cells was increased after treatment with Exo derived from A549 cells(P<0.05).compared with control group,the expression level of lncRNA DUXAP8 in the A549 cells in Exo group was increased(P<0.05);compared with Exo group,the expression level of lncRNA DUXAP8 in the A549 cells in Exo+sh-DUXAP8 group was decreased(P<0.05),while there were no significant difference in the expression level of IncRNA DUXAP8 in the cells in Exo+sh-NC group(P>0.05).The colony formation assay results showed that compared with control group,the number of colony formation of the A549 cells in Exo group was increased(P<0.05);compared with Exo group,the number of colony formation of the A549 cells in Exo+sh-DUXAP8 group was decreased(P<0.05),while there was no significant difference in the number of colony formation of the A549 cells in Exo+sh-NC group(P>0.05).The EdU staining results showed that compared with control group,the EdU-positive rate of the A549 cells in Exo group was increased(P<0.05);compared with Exo group,the EdU-positive rate in A549 cells in Exo+sh-DUXAP8 group was decreased(P<0.05),while there was no significant difference in the EDU-positive rate in the cells in Exo+sh-NC group(P>0.05).The flow cytometry results showed that compared with control group,the percentage of activated CD8+T lymphocytes in the human peripheral blood lymphocytes in Exo group was decreased(P<0.05);compared with Exo group,the percentage of activated CD8+T lymphocytes in the human peripheral blood lymphocytes in Exo+sh-DUXAP8 group was increased(P<0.05),while there was no significant difference in the percentage of activated CD8+T lymphaytes in Exo+sh-NC group(P>0.05).The MTT assay results showed that compared with control group,the killing rate of human peripheral blood lymphocytes on the A549 cells in Exo group was decreased(P<0.05);compared with Exo group,the killing rate of human peripheral blood lymphocytes on A549 cells in Exo+sh-DUXAP8 group was increased(P<0.05),while no significant difference was observed in Exo+sh-NC group(P>0.05).Conclusion:The lncRNA DUXAP8 in exosomes derived from the lung cancer A549 cells promotes the proliferation of lung cancer cells and tumor immune escape.

Objective:To investigate the role and underlying mechanisms of methyltransferase (Mettl) 3 in the process of angiotensin Ⅱ (Ang Ⅱ)-induced pericyte-to-myofibroblast transdifferentiation and renal fibrosis.Methods:C57BL/6J mice were used, in cell experiments, mouse renal pericytes were isolated and cultured using magnetic bead sorting. These pericytes were then induced to transdifferentiate into myofibroblasts with 1×10 6 mmol/L Ang Ⅱ, which was the Ang Ⅱ group, while pericytes cultured in normal conditions served as the control group. Successful transdifferentiation was verified by immunofluorescence staining, Western blotting, and real-time reverse transcription PCR (RT-qPCR) for α-smooth muscle actin (α-SMA). The levels of m6A modifications and related enzymes (Mettl3, Mettl14), Wilms tumor 1-associated protein (WTAP), fat mass and obesity protein (FTO), ALKBH5, YTHDF1, YTHDF2, YTHDC1, YTHDC2, YTHDC3 were assessed by Dot blot, RT-qPCR and Western blot. Mettl3 expression was inhibited in cells using lentivirus-mediated Mettl3-shRNA transfection, creating sh-Mettl3 and Ang Ⅱ+sh-Mettl3 groups, while lentivirus empty vector transfection served as the negative control (Ang Ⅱ+sh-NC group). The impact of Ang Ⅱ on pericyte transdifferentiation was observed, and the expression of downstream phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway proteins, including PI3K, AKT, phosphorylated AKT at serine 473 (p-AKT (S473)), and phosphorylated AKT at threonine 308 (p-AKT (T308)), were examined. PI3K gene transcription was inhibited by co-culturing cells with actinomycin D, and the half-life of PI3K mRNA was calculated by measuring residual PI3K mRNA expression over different co-culture time. The reversibility of Mettl3 inhibition on Ang Ⅱ-induced pericyte-to-myofibroblast transdifferentiation was assessed by adding the AKT activator SC79 to the Ang Ⅱ+sh-Mettl3 group. In animal experiments, mice were divided into these groups: sham group (administered 0.9% sterile saline), Ang Ⅱ group (infused with Ang Ⅱ solution), sh-Mettl3 group (injected with Mettl3 shRNA lentivirus solution), Ang Ⅱ+sh-Mettl3 group (infused with Ang Ⅱ solution and injected with Mettl3 shRNA lentivirus solution), and Ang Ⅱ+sh-Mettl3+SC79 group (administered Ang Ⅱ solution and Mettl3 shRNA lentivirus, with an additional injection of SC79). Each group consisted of six subject mice. Blood pressure was measured using the tail-cuff method before and after surgery, and serum creatinine, urea, and urinary albumin levels were determined 4 weeks post-surgery. Kidney tissues were collected at 28 days and stained using hematoxylin-eosin (HE) and Masson′s trichrome to assess the extent of renal fibrosis. Results:Primary renal pericytes were successfully obtained by magnetic bead sorting, and intervened with 1×10 6 mmol/L Ang Ⅱ for 48 hours to induce pericyte-to-myofibroblast transdifferentiation. Dot blot results indicated higher m6A modification levels in the Ang Ⅱ group compared to the control group ( P<0.05). RT-qPCR and Western blot results showed upregulation of Mettl3 mRNA and protein levels in the Ang Ⅱ group compared to the control group (both P<0.05). In the Ang Ⅱ+sh-Mettl3 group, Mettl3 protein expression was lower than that in the Ang Ⅱ group, with reduced expression levels of α-SMA, vimentin, desmin, fibroblast agonist protein (FAPa) and type Ⅰ collagen (all P<0.05). Compared to the control group, PI3K mRNA expression level was elevated in the Ang Ⅱ group, along with increased p-AKT (S473) and p-AKT (T308) expressions. In the Ang Ⅱ+sh-Mettl3 group, PI3K mRNA expression and p-AKT (S473) and p-AKT (T308) levels were decreased (all P<0.05). The half-life of PI3K mRNA was shorter in the Ang Ⅱ+sh-Mettl3 group than that in the Ang Ⅱ+sh-NC group (2.34 h vs. 3.42 h). The ameliorative effect of Mettl3 inhibition on Ang Ⅱ-induced pericyte-to-myofibroblast transdifferentiation was reversible by SC79. Animal experiments showed higher blood pressure, serum creatinine, urea, and 24-hour urinary protein levels, and a larger fibrosis area in the Ang Ⅱ group compared to the sham group (all P<0.05). The fibrosis area was smaller in the Ang Ⅱ+sh-Mettl3 group than that in the Ang Ⅱ group ( P<0.05), but increased again upon addition of SC79. Conclusion:Mettl3-mediated RNA m6A epigenetic regulation is involved in Ang Ⅱ-induced pericyte-to-myofibroblast transdifferentiation and renal fibrosis, potentially by affecting PI3K stability and regulating the PI3K/AKT signaling pathway.

  Objective  To explore the mechanism of Wnt5a on keratinocyte involved in the peripheral sensitization of complex regional pain syndrome type-Ⅰ (CRPS-Ⅰ) by regulating the expression of MMP9, and search for potential therapeutic strategies.  Methods  Cultured HaCaT cells were treated with oxygen glucose deprivation/re-oxygenation (OGD/R). The early stage of mitochondrial damage and membrane potential changes after OGD/R and the effects of Box5 (Wnt5a inhibitor) at different concentrations (20 μmol/L, 40 μmol/L) on MMP9 were explored. Adult male Sprague-Dawley rats were divided into Control group(n=8), CPIP group (n=8), Box5 (20) group (n=8) and Box5 (40) group (n=8). The rat chronic post-ischemia pain (CPIP) model was established to mimic the pathophysiological process of CRPS-Ⅰ. Box5 (20) group and Box5 (40) group were treated with intraplantar injection of 20 μmol/L and 40 μmol/L Box5 100 μL, respectively. The changes of mechanical withdrawal threshold and thermal withdrawal latency were measured within two weeks, and the skin inflammatory infiltration and keratosis were observed by HE staining. The expression of MMP9 was observed by immunofluorescence, and the levels of IL-1β and TNF-α in dorsal root ganglion of different groups were detected by ELISA.  Results  Vitro experiment: After OGD/R treatment, the mitochondrial atrophy was observed in OGD/R group under transmission electron microscope and the average fluorescence intensity of MMP9 was found to increase significantly (P<0.001). Compared with Control group, the mitochondrial membrane potential in OGD/R group decreased significantly by JC-1 detection (P=0.027). Compared with OGD/R group, only Box5 (40) group had a statistically significant increase in mitochondrial membrane potential (P=0.046). Animal experiment: Behavioral tests showed that the mechanical pain threshold and thermal pain threshold of CPIP group were significantly decreased at each time point (D1, D2, D4, D10, D14) (all P<0.05). HE staining indicated that there was a large-scale infiltration of inflammatory cell in the dermis and excessive keratosis in the epidermis, and the thickness of stratum granulosum and stratum spinosum increased significantly (P < 0.001). Immunofluorescence analysis showed that the expression of MMP9 in CPIP group was significantly increased (P<0.001). Compared with CPIP group, the fluorescence intensity of MMP9 in Box5 (20) group (P=0.002) and Box5 (40) group (P<0.001) were significantly decreased. ELISA results showed that the concentrations of IL-1β (P=0.048) and TNF-α (P=0.002) in CPIP group were significantly increased. Compared with CPIP group, the concentrations of IL-1β (P=0.047) and TNF-α (P=0.047) were significantly decreased in Box5 (40) group.  Conclusions  Peripheral ischemia reperfusion injury leads to overexpression of MMP9 on keratinocytes, resulting in CRPS-Ⅰ peripheral sensitization. Targeted inhibition of Wnt5a/MMP9 pathway can reverse pain behavior in rat model of CPIP, thus providing a strategy for clinical treatment of chronic pain.

  Objective  To elucidate whether coffee consumption and caffeine intake was associated with various subtypes of pain based on extensive data from publicly accessible databases.  Methods  The information was extracted from three cycles of the American National Health and Nutrition Examination Survey (1999—2000, 2001—2002, 2003—2004), encompassing data on coffee consumption, pain information, and 11 covariates (including age, gender, race, etc.). Multinomial logistic regression in three models were utilized for analysis.  Results  A total of 13 428 participants were included in this study, with a mean age of (49.79±19.06)years and a male-to-female ratio of 0.9∶1. Daily coffee intake: non-drinker 7794(58.0%), > 0-2 cups 2077(15.5%), > 2 cups 3557(26.5%); daily caffeine intake: without intake 7794(58.0%), > 0-200 mg 3152(23.5%), > 200 mg 2482(18.5%); pain situation: no pain or pain duration < 24 h 10 202(76.0%), acute pain 910(6.8%), subacute pain 369(2.7%), chronic pain 1947(14.5%). After weighting, 13 428 participants were expected to represent 190 million(190 709 157) U.S. citizens aged ≥20 years, and the overall prevalence of acute, subacute, and chronic pain in the U.S. population during that period was estimated to be 8%, 3%, and 16%, respectively. Without adjusting for covariates, individuals who consumed more than 2 cups of coffee or 200 mg of caffeine per day exhibited an elevated risk of chronic pain compared to non-coffee/caffeine drinkers, with an odds ratio of 1.354(95% CI: 1.187-1.544) and 1.372(95% CI: 1.185-1.587), respectively. After adjusting for partial covariates including age, sex, and race, individuals who consumed more than 2 cups of coffee or more than 200 mg of caffeine per day still demonstrated an increased risk of chronic pain with an odds ratio of 1.243(95% CI: 1.083-1.427) and 1.249 (95% CI: 1.072-1.456), respectively. However, after all covariates were adjusted, there was no significant association between coffee/caffeine consumption and chronic pain. Furthermore, the number of cups of coffee consumed or caffeine intake showed no significant correlation with acute and subacute pain.  Conclusions  Compared with nondrinkers, heavy daily coffee drinkers may be more likely to have chronic pain, but it is affected by multiple factors. Basic research and prospective clinical studies are needed to further determine the causality in this association.

Objective:To investigate the therapeutic effect of methotrexate loaded vesicles on experimental periodontitis in mice.Methods:Extracellular vesicles (EVs) were isolated from human umbilical cord mesenchymal stem cells (hUC-MSC). Methotrexate loaded vesicles (MTX-EVs) were constructed, whose morphology and size were analyzed by using scanning electron microscopy and particle size analyzer. Western blotting was used to identify their surface specific proteins. C57BL/6J male mice of 4-5 weeks (provided by Experimental Animal Center of The Fourth Military Medical University) were selected, among which 8 were randomly selected by blind grasp method without treatment and fed normally as normal group, and others were induced to periodontitis models by local injection of lipopolysaccharide (LPS) into the periodontium. The LPS was injected once every day with a concentration of 2 g/L and a volume of 5 μl, lasting for two weeks. The mice with successfully induced periodontitis were randomly divided into 4 groups by blind grasping method, with 8 mice in each group. The LPS group was with no treatment, and the other three groups were treated with periodontal local injection of MTX, EVs or MTX-EVs, respectively. Two weeks later, enzyme-linked immunosorbent assay (ELISA) was used to detect the expressions of inflammatory cytokine interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) in gingival tissue. The amount of alveolar bone resorption of four groups was detected by using micro-CT scanning and HE staining. The expression proportion of the inflammatory factor in gingival tissue was analyzed by using flow cytometry.Results:The scanning electron microscopy results showed that EVs and MTX-EVs were circular or elliptical in shape. Dynamic light scattering (DLS) particle size analysis showed that the particle size of EVs was around 200 nm, while that of MTX-EVs was around 300 nm. The ELISA results showed IL-1β levels in the normal group, LPS group, LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group were (28.86±2.76), (51.50±2.04), (35.26±2.40), (45.49±2.04) and (35.77±3.49) ng/L. That is, the IL-1β concentrations in the LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group were significantly lower than that in the LPS group ( P<0.05); the mass concentration of IL-1β in the LPS +MTX-EVs group was significantly lower than that in the LPS+EVs group ( P<0.05). The concentrations of IL-6 in the normal group, LPS group, LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group were (125.44±4.12), (221.64±10.59), (178.16±16.90), (181.09±18.22) and (170.15±9.04) ng/L, among which the concentration of IL-6 in the last three groups were significantly lower than that in the LPS group ( P<0.05). The mass concentration of IL-6 in the LPS+MTX-EVs group was significantly lower than those in the LPS+MTX group and LPS+EVs group ( P<0.05). The concentrations of TNF-α in the normal group, LPS group, LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group were (320.27±38.68), (479.62±40.94), (342.18±25.89), (415.88±12.01) and (325.75±30.83) ng/L, among which the concentrations of last three groups were significantly lower than the LPS group ( P<0.05); the mass concentration of TNF-α in the LPS+MTX-EVs group was significantly lower than those in the LPS+EVs group and LPS+MTX group ( P<0.05). The micro-CT results showed that the distance of cement-enamel junction-alveolar bone crest (CEJ-ABC) of the first molar and root (M1R1) in the normal group, LPS group, LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group of mice were (0.11±0.03), (0.28±0.02), (0.23±0.03), (0.20±0.04), and (0.18±0.03) mm, respectively. Compared with the LPS group, the CEJ-ABC of the M1R1 in the LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group were inhibited to varied degrees with statistically significant differences ( P<0.05). Among them, LPS+MTX-EVs group had the best bone resorption inhibitioin effect compared to LPS+MTX group and LPS+EVs group, and the differences were statistically significant ( P<0.05). The flow cytometry results indicated that the proportion of interferon-γ (IFN-γ) positive cells was (11.77±1.02)% in the LPS group, (6.87±0.65)% in the LPS+EVs group, and (4.15±0.92)% in the LPS+MTX-EVs group, respectively. The proportions of IFN-γ positive cells in the LPS+EVs group and LPS+MTX-EVs group were significantly lower than that in the LPS group ( P<0.05), while the ratio of IFN-γ positive cells in the LPS+MTX-EVs group was found significantly lower than that in the LPS+EVs group ( P<0.05). Conclusions:MTX-EVs can effectively alleviate the periodontal local inflammatory environment and reduce bone resorption of alveolar bone in periodontitis model mice.