Objective To investigate the distribution characteristics of pathogens causing infections within 90 days after liver transplantation and the influencing factors of infection. Methods Clinical data of 176 recipients who underwent liver transplantation at the Liver Transplant Center of Beijing Friendship Hospital Affiliated to Capital Medical University from September 2021 to August 2024 were retrospectively analyzed. Patients were divided into the infection group (n=124) and the non-infection group (n=52) based on whether they developed infection within 90 days after transplantation. The distribution characteristics of pathogens in infected patients were analyzed. Univariate and multivariate logistic regression analyses were used to explore the influencing factors of infection. Results Among the 176 liver transplant recipients, 124 cases developed 243 episodes of 518 bacterial, fungal, viral or mycoplasma infections within 90 days after transplantation, with an overall infection rate of 70.5% (124/176). The composition of pathogens was mainly Gram-negative bacteria (38.6%, 200/518), followed by Gram-positive bacteria (32.2%, 167/518) and viruses (15.4%, 80/518), and fungi accounted for 13.1% (68/518). Among Gram-negative bacteria, the main pathogen was Klebsiella pneumoniae (6.8%, 35/518), and among Gram-positive bacteria, the main pathogen was Enterococcus faecalis (8.5%, 44/518). Viruses included Epstein-Barr virus (3.7%, 19/518) and cytomegalovirus (3.7%, 19/518), and fungi were mainly Candida albicans (6.8%, 35/518). The most common infection site among the 243 episodes was pulmonary infection (42.0%, 102/243), followed by abdominal infection (22.6%, 55/243) and bloodstream infection (18.1%, 44/243). The infections mainly occurred within 2 weeks after transplantation (60.9%, 148/243). Multivariate logistic regression analysis indicated that preoperative infection within 2 weeks, a high preoperative model for end-stage liver disease (MELD) score, and preoperative sarcopenia were independent risk factors for infection within 90 days after liver transplantation (all odds ratio>1, P<0.05). After multivariate correction, the levels of CD4⁺T cells and CD8⁺T cells within 90 days after surgery were independently associated with the occurrence of infection. Low levels of CD4⁺T cells and CD8⁺T cells might be related to an increased risk of infection. Conclusions The infection rate after liver transplantation is high, and the pathogens are mainly Gram-negative bacteria. The lungs are the most common infection site. Preoperative MELD score, preoperative sarcopenia and preoperative infection within 2 weeks are independent risk factors for infection within 90 days after liver transplantation. Regular monitoring of immune indicators CD4⁺T cells and CD8⁺T cells levels after transplantation is helpful to reduce the occurrence of post-transplantation infection.

Objective To investigate the therapeutic efficacy of artesunate(AS)on polycystic ovary syndrome(PCOS)in mice and explore the potential mechanism primarily.Methods Twenty-five female C57BL/6J mice were randomly divided into Control group,model group(PCOS group),low-and high-dose AS groups(AS15 and AS30 groups)and metformin group(Met group).In addition to the Control group,the mouse model of PCOS was established by subcutaneous injection of dehydroepiandrosterone(DHEA,60 mg/kg)following by a high-fat diet for 21 d.After modeling,AS of 15 and 30 mg/kg was intraperitoneally injected into the mice of the AS 15 and AS30 groups,respectively,and 200 mg/kg Met was given to those of the Met group by gavage,once per day,for 6 weeks.ELISA was used to detect serum testosterone(T),fasting insulin(FINS),luteinizing hormone(LH)and follicle-stimulating hormone(FSH),and the LH/FSH ratio was calculated.The levels of fasting blood glucose(FBG),triglyceride(TG)and total cholesterol(TC)were detected by automatic biochemical analyzer,and the homeostasis model assessment of insulin resistance(HOMA-IR)was calculated.The estrous cycle was observed,and HE staining was performed for pathological changes in the ovary and uterus.Immunofluorescence assay was employed to measure the expression of p-eIF2α,ATF4 and CHOP in the ovarian tissue.After steroidogenic human granulosa-like tumor cell line KGN were exposed to 100 μmol/L DHEA to simulate the hyperandrogen environment of PCOS,and then treated with 5 and 10 μg/mL AS for 24 h,the protein levels of endoplasmic reticulum stress signaling pathway was detected by Western blotting.Results Compared with the Control group,the PCOS mice had disturbed estrous cycle,polycystic changes in the ovaries,and significantly increased serum T level and LH/FSH ratio(P＜0.05),and obviously elevated HOMA-IR,TC and TG levels in terms of metabolism(P＜0.01).The expression levels of p-eIF2α,ATF4 and CHOP were notably up-regulated in the ovarian granulosa cells of PCOS mice and KGN cells after DHEA exposure(P＜0.05).Additionally,AS treatment attenuated the pathological changes of ovary and uterine expression,decreased the serum T level and the LH/FSH ratio(P＜0.05),and reduced HOMA-IR,TC and TG levels(P＜0.05)when compared with the PCOS mice.Moreover,the expression levels of p-eIF2α,ATF4 and CHOP were significantly down-regulated after AS treatment in both ovarian granulosa cells of PCOS mice and KGN cells(P＜0.05).Conclusion AS significantly improves glycolipid metabolic disorder and reproductive dysfunction in PCOS mice,which may be associated with its suppressing endoplasmic reticulum stress by inhibiting the PERK/eIF2α/ATF4/CHOP pathway.

Objective To investigate the role of p300 in lipid metabolism disorders.Methods Bioinformatics analysis was performed to analyze the expression patterns of p300 in lipid metabolism disorder-related diseases and its correlation with SREBP-1c and downstream lipid metabolic enzymes.Immunofluorescence assay was used to detect the expression of p300 in the liver tissues of the patients with varying disease severity of non-alcoholic fatty liver disease(NAFLD).A mouse model of lipid metabolism disorder was established in male C57BL/6J mice by feeding high-fat diet(HFD)for 12 weeks.Western blotting was employed to assess p300 expression level in the liver tissues of HFD-fed mice.A cell model of lipid metabolism disorder was established in HepG2/AML-12 cells induced with free fatty acid(FFA).The effects of siRNA-mediated knockdown of p300 was observed to measure the levels of intracellular total cholesterol(TC)and triglyceride(TG),lipid deposition,and production of reactive oxygen species(ROS).Results Clinically,p300 was highly expressed in lipid metabolism disorders,and its level was positively correlated with NAFLD severity(P<0.05).Gene Set Enrichment Analysis(GSEA)revealed that p300 expression was significantly associated with fatty acid metabolism,cholesterol homeostasis,lipogenesis,PPAR signaling pathway,and peroxisome pathway.In vivo,p300 was significantly up-regulated in the livers of HFD-fed mice(P<0.01).In vitro,FFA stimulation markedly increased p300 expression in both HepG2 and AML-12 cells(P<0.01),whereas p300 knockdown significantly reduced intracellular TG and TC levels(P<0.01),attenuated lipid droplet accumulation,and reversed FFA-induced ROS elevation(P<0.01).Furthermore,p300 expression was positively correlated with the expression of SREBP-1c and its downstream key lipid synthesis enzymes.Conclusion p300 may promote hepatic lipid accumulation by acetylating and activating SREBP-1c and regulating downstream lipid metabolic enzymes,thereby affecting lipid synthesis and oxidative stress.These findings suggest that p300 may be a potential therapeutic target for lipid metabolism disorder-related diseases.

Arsenic is a semi-metal,and lipid-soluble arsenic compounds are one of the widespread forms in the environment and food chain,but there is a lack of standards for lipid-soluble arsenic compounds,which is one of the bottlenecks in the current analytical detection and toxicological studies of organic arsenic.In this study,four saturated arsenic-containing hydrocarbons,AsHC 318,AsHC 332,AsHC 346,and AsHC 374(The number is relative molecular mass),were successfully synthesized in three steps by using dimethylarsinic acid,potassium iodide,sodium hydroxide,and four brominated alkanes(1-Bromotetradecane,1-bromopentadecane,1-bromohexadecane,and 1-bromooctadecane)as raw materials.The structures of these four saturated arsenic-containing hydrocarbons were characterized by proton nuclear magnetic resonance(1H NMR)spectroscopy,13C nuclear magnetic resonance(13C NMR)spectroscopy,and high-resolution mass spectrometry(HR-MS).The yields of the method were 8%-10%,and the synthesized compounds could be used in subsequent toxicity evaluation experiments to assess the toxic effects and mechanisms of action of arsenic-containing hydrocarbons.This study provided an effective method for synthesis of arsenic-containing hydrocarbons,enriching the synthesis methods of arsenic-containing hydrocarbons,and provided raw materials for the subsequent toxicological studies of arsenic-containing hydrocarbons.

Objective:To investigate the effects of metformin on esophageal squamous cell carcinoma cell growth, migration and angiogenesis by regulating the expression of ALKBH3.Methods:Human esophageal cancer TE-1 cells were treated with different concentrations (0, 0.5, 1.0, 2.0, 4.0, 8.0 mmol/L) of metformin, and they were divided into a blank control group, low- (0.5 mmol/L), medium- (1.0 mmol/L), and high- (2.0 mmol/L) concentration metformin groups, a metformin (2.0 mmol/L) +pcDNA-NC group, and a metformin (2.0 mmol/L) +pcDNA-ALKBH3 group. The cell viability was determined by the CCK-8 method. The cell proliferation ability was detected by the clone formation assay. The cell migration and invasion abilities were examined by the Transwell assay. The cell apoptosis was detected by flow cytometry. The tube formation ability of cells was detected by the angiogenesis assay. A xenograft tumor model was constructed using 4- to 6-week-old male BALB/c thymus-less nude mice, which were divided into a model control group, a metformin group, a metformin+pcDNA-NC group, and a metformin+pcDNA-ALKBH3 group using a random number table method, and with six in each group. And the volume and weight of the tumor were measured. The protein expression levels of apoptosis-related proteins Bcl-2, Bax, ALKBH3 and vascular endothelial growth factor A (VEGF-A) were detected by Western blotting. The expression of CD31 protein was detected by immunohistochemistry.Results:After treating TE-1 cells with 0, 0.5, 1.0, 2.0, 4.0, and 8.0 mmol/L metformin for 48 hours, the cell viability was (100.00±0.00) %, (90.31±5.23) %, (81.25±8.65) %, (63.52±6.80) %, (54.64±5.35) %, and (31.48±4.21) %, respectively, with a statistically significant difference ( F=98.11, P<0.001). There were statistically significant differences in cell viability between 0.5, 1.0, 2.0, 4.0, 8.0 mmol/L and 0 mmol/L (all P<0.05). The IC 50 of metformin for TE-1 cells was 4.46 mmol/L. The numbers of colony formations of TE-1 cells in the blank control group, low-, medium-, and high-concentration metformin groups, metformin+pcDNA-NC group, and metformin+pcDNA-ALKBH3 group were 153.15±13.55, 134.80±11.62, 116.24±10.43, 93.17±8.85, 89.39±8.46, 110.26±7.21, respectively, with a statistically significant difference ( F=34.28, P<0.001); the numbers of colony formations of TE-1 cells in the metformin groups at different concentrations decreased significantly with the increase in metformin concentration (both P<0.05); compared with the metformin+pcDNA-NC group, the number of colony formations of cells in the metformin+pcDNA-ALKBH3 group increased ( P<0.05). The numbers of migration of TE-1 cells of 6 groups were 152.13±13.40, 133.85±10.72, 115.28±8.64, 91.16±7.89, 85.39±7.23, 116.85±8.36, the numbers of invasion were 135.22±10.77, 112.07±9.53, 86.30±7.45, 69.53±6.74, 65.81±5.65, 79.80±6.32, respectively, with statistically significant differences ( F=41.35, P<0.001; F=69.06, P<0.001); the numbers of migrated and invaded cells in the metformin groups at different concentrations decreased significantly with the increase in metformin concentration (all P<0.05); compared with the metformin+pcDNA-NC group, the numbers of migrated and invaded cells in the metformin+pcDNA-ALKBH3 group increased significantly (both P<0.05). The apoptosis rates of TE-1 cells in 6 groups were (3.22±1.13) %, (13.82±1.90) %, (22.67±2.53) %, (29.18±3.24) %, (26.84±2.75) %, and (16.36±1.63) %, respectively, with a statistically significant difference ( F=103.66, P<0.001); the apoptosis rates of cells in the metformin groups at different concentrations gradually increased with the increase in metformin concentration (both P<0.05); compared with the metformin+pcDNA-NC group, the apoptosis rate of cells in the metformin+pcDNA-ALKBH3 group was relatively lower ( P<0.05). The tubular structure of cells in blank control group was intact, and there were different degrees of damage to the tubular structure of cells in the low-, medium-, high- concentration metformin groups, the degree of damage to the tubular structure of cells in the metformin+pcDNA-ALKBH3 group was reduced. The numbers of cellular tubular structures of TE-1 cells in the 6 groups were 38.35±3.20, 27.15±2.64, 15.92±3.14, 7.39±1.50, 8.61±1.37, and 29.33±4.20, respectively, with a statistically significant difference ( F=113.92, P<0.001); the number of cellular tubular structures in the low-, medium-, and high- concentration metformin groups gradually decreased (both P<0.05); the number of cellular tubular structures in the metformin+pcDNA-ALKBH3 group was more than that in the metformin+pcDNA-NC group ( P<0.05). There were statistically significant differences in the protein expressions of Bcl-2, Bax, ALKBH3, and VEGF-A in TE-1 cells among 6 groups ( F=56.36, P<0.001; F=57.26, P<0.001; F=159.30, P<0.001; F=132.89, P<0.001); compared with the blank control group, the protein expressions of Bcl-2, ALKBH3, and VEGF-A in the metformin groups at different concentrations decreased, while the protein expression of Bax increased (all P<0.05); compared with the metformin+pcDNA-NC group, the protein expressions of Bcl-2, ALKBH3, and VEGF-A in the metformin+pcDNA-ALKBH3 group increased, and the expression level of Bax decreased (all P<0.05). The weights of tumors in the model control group, metformin group, metformin+pcDNA-NC group, and metformin+pcDNA-ALKBH3 group were (1.16±0.12), (0.46±0.05), (0.50±0.06), (1.19±0.14) g, the volumes of tumors were (878.36±108.93), (413.59±50.23), (439.78±51.39), (793.75±96.98) mm 3, with statistically significant differences ( F=96.61, P<0.001; F=51.90, P<0.001); the weight of tumors were lower and the volume of tumors were smaller in the metformin group than those in the model control group (both P<0.05), the weight of tumors were higher and the volume of tumors were bigger in the metformin+pcDNA-ALKBH3 group than those in the metformin group and the metformin+pcDNA-NC group (all P<0.05). CD31 was mainly distributed in the cytoplasm and cell membrane of tumor cells. There were statistically significant differences in the positive rates of CD31 and the protein expression levels of VEGF-A in transplanted tumor tissues among 4 groups ( F=7.12, P=0.002; F=48.81, P<0.001); the positive rate of CD31 and the protein expression level of VEGF-A in the metformin group were lower than those in the model control group; the positive rate of CD31 and the protein expression level of VEGF-A in the metformin+pcDNA-ALKBH3 group were higher than those in the metformin group and the metformin+pcDNA-NC group (all P<0.05) . Conclusions:Metformin may inhibit the proliferation, migration, and tumor angiogenesis of esophageal squamous cell carcinoma by reducing ALKBH3 expression.

Based on whole-genome identification of the TPS gene family in Perilla frutescens and screening, cloning, bioinformatics, and expression analysis of the synthetic enzyme for the insect-resistant component germacrene D, this study lays the foundation for understanding the biological function of the TPS gene family and the insect resistance mechanism in P. frutescens. This study used bioinformatics tools to identify the TPS gene family of P. frutescens based on its whole genome and predicted the physicochemical properties, systematic classification, and promoter cis-elements of the proteins. The relative content of germacrene D was detected in both normal and insect-infested leaves of P. frutescens, and the germacrene D synthase was screened and isolated. Gene cloning, bioinformatics analysis, and expression profiling were then performed. The results showed that a total of 99 TPS genes were identified in the genome, which were classified into the TPS-a, TPS-b, TPS-c, TPS-e/f, and TPS-g subfamilies. Conserved motif analysis showed that the TPS in P. frutescens has conserved structural characteristics within the same subfamily. Promoter cis-element analysis predicted the presence of light-responsive elements, multiple hormone-responsive elements, and stress-responsive elements in the TPS family of P. frutescens. Transcriptome data revealed that most of the TPS genes in P. frutescens were highly expressed in the leaves. GC-MS analysis showed that the relative content of germacrene D significantly increased in insect-damaged leaves, suggesting that it may act as an insect-resistant component. The germacrene D synthase gene was screened through homologous protein binding gene expression and was found to belong to the TPS-a subfamily, encoding a 64.89 kDa protein. This protein was hydrophilic, lacked a transmembrane structure and signal peptide, and was predominantly expressed in leaves, with significantly higher expression in insect-damaged leaves compared to normal leaves. In vitro expression results showed that germacrene D synthase tended to form inclusion bodies. Molecular docking showed that farnesyl pyrophosphate(FPP) fell into the active pocket of the protein and interacted strongly with six active sites. This study provides a foundation for further research on the biological functions of the TPS gene family in P. frutescens and the molecular mechanisms underlying its insect resistance.
Perilla frutescens/chemistry* ; Plant Proteins/chemistry* ; Multigene Family ; Sesquiterpenes, Germacrane/metabolism* ; Alkyl and Aryl Transferases/chemistry* ; Phylogeny ; Gene Expression Regulation, Plant

OBJECTIVE To explore the in vitro and in vivo inhibitory effects and mechanism of metformin on the malignant biological behavior of esophageal squamous cell carcinoma （ESCC） cells by the hypoxia inducible factor-1α （HIF-1α）/interleukin-8 （IL-8） signaling pathway. METHODS Human ESCC TE1 cells were assigned into blank group， metformin low-， medium-， and high-dose groups （0.5， 1， 2 mmol/L）， IDF-11774 （HIF-1α inhibitor） group （20 μmol/L）， and high-dose metformin+HIF-1α activator dimethyloxalylglycine （DMOG） group. After 24 h treatment， cell proliferation [measured by the positive rate of 5-ethynyl- 2′-deoxyuridine （EdU） and optical density at 450 nm （OD450 value）]， apoptosis， invasion and migration as well as mRNA expressions of proliferating cell nuclear antigen （PCNA）， Bcl-2 interacting mediator of cell death （Bim）， migration and invasion enhancer 1 （MIEN1）， and matrix metalloproteinase-9 （MMP-9）， and protein expressions of HIF-1α and IL-8 in the cells were detected. The xenograft tumor model of nude mice was established. Thirty nude mice were randomly divided into blank group， metformin low-， medium-， and high-dose groups （i.g. administration of metformin 62.5， 125， 250 mg/kg+i.p. administration of equal volume of normal saline）， IDF-11774 group （i.g. administration of 50 mg/kg IDF-11774+i.p. administration of equal volume of normal saline） and high-dose metformin+DMOG group （i.g. administration of metformin 250 mg/kg+i.p. administration of DMOG 250 mg/kg）， with 5 mice in each group. They were given relevant medicine， once a day， for 4 consecutive weeks； the mass and volume of the tumor and protein expressions of HIF-1α and IL-8 in the tumor tissue were determined. RESULTS The EdU positive rate， OD450 value， cell invasion number， scratch healing rate， mRNA expressions of PCNA， MIEN1 and MMP-9， protein expressions of HIF-1α and IL-8， as well as the mass and volume of transplanted tumors and protein expressions of HIF-1α and IL-8 in tumor tissues were decreased by metformin in concentration/dose-dependent manner （P＜0.05）. Additionally，metformin increased the apoptosis rate and mRNA expression of Bim in cells （P＜0.05）. The trend of changes in corresponding indicators in the IDF-11774 group was consistent with that in the metformin groups， whereas DMOG could significantly attenuate the aforementioned effects of high-concentration/high-dose metformin （P＜0.05）. CONCLUSIONS Metformin can inhibit the proliferation， invasion， migration of TE1 cells， and tumor growth of nude mice， and induce cell apoptosis， the mechanism of which may be related to the inhibition of HIF-1α/IL-8 signaling pathway.

Objective To explore the effect of PCSK9 inhibitor combined with atorvastatin on carotid atherosclerosis and its anti-inflammatory effect in patients with hypertension complicated with type 2 diabetes mellitus.Methods A total of 100 patients with hypertension complicated with type 2 diabetes mellitus who were treated in Nanchang Third Hospital from October 2022 to August 2023 were selected as the research subjects.They were divided into the control group and the study group by the random number table method,with 50 cases in each group.Both groups of patients received conventional antihypertensive,hypoglycemic,and antiplatelet therapy.The control group took 20 mg of atorvastatin calcium tablets orally,once a night.On the basis of the control group,the study group was additionally given 150 mg of evolocumab injection(a PCSK9 inhibitor)by subcutaneous injection,once every two weeks.Both groups of patients were followed up for 24 weeks.The levels of blood lipids,blood glucose,inflammatory cytokines,carotid intima-media thickness(IMT),atherosclerotic plaque score and adverse reactions of the patients in the two groups before and after treatment were detected and compared.Results The levels of TC,TG and LDL-C in the study group after treatment were lower than those before treatment and those in the control group at the same period,and the differences were statistically significant(P＜0.05).The levels of IL-1,IL-6,TNF-α,hs-CRP,as well as the ca-rotid IMT and atherosclerotic plaque score in the study group after treatment were lower than those before treatment and those in the control group at the same period,and the differences were statistically significant(P＜O.05).During the treatment period,there was no significant difference in the occurrence of adverse reac-tions between the two groups(P＞0.05).Conclusion The combination of PCSK9 inhibitor and atorvastatin can effectively regulate the blood lipid levels of patients with hypertension complicated and type 2 diabetes mellitus,alleviate the inflammatory response,and improve the degree of carotid atherosclerosis in these pa-tients.

ObjectiveTo analyze the epidemiological characteristics and spatial clustering patterns of brucellosis in humans in Zhangjiakou City, Heibei Province from 2018 to 2023, so as to provide a basis for the prevention and control of brucellosis. MethodsIncidence data of brucellosis in Zhangjiakou City from 2018 to 2023 were collected. Descriptive epidemiological analysis, Joinpoint regression modelling, and spatial autocorrelation analysis were used to analyze the temporal trends and spatial clustering patterns of the epidemic. ResultsA total of 3 812 cases of brucellosis were reported in Zhangjiakou City from 2018 to 2023, with no death case, yielding an average annual incidence rate of 15.43/100 000 (incidence range: 12.82/100 000‒17.76/100 000). Cases of brucellosis occurred year-round, with a distinct seasonal pattern, predominantly concentrated between March and September, peaking in May and June. The male-to-female ratio was 2.58∶1, with a higher incidence in males than that in females. The highest incidence rates were observed in the 40‒<50 years (74.98/100 000) and 50‒<60 years age group (87.14/100 000). The majority of cases were farmers and herdsmen (3 557 cases, 93.31%). Joinpoint regression analyses indicated that from 2018 to 2023, the incidence rate of human brucellosis in pastoral areas of Zhangjiakou City showed a declining trend (APC=-9.70%, 95%CI: -15.31%‒ -4.63%), while the incidence rate in mixed-use areas exhibited an increasing trend (APC=6.90%, 95%CI: 0.17%‒14.30%). Spatial clustering analyses showed that the incidence of brucellosis in Zhangjiakou from 2018 to 2023 was non-randomly distributed across the whole city, with a positive spatial correlation and significant clustering (Moran’s I>0, all P<0.001). Local spatial autocorrelation analyses showed that the high-high clusters were concentrated in the pastoral areas during 2018‒2020. From 2021 onward, the number of high-high clusters in mixed and non-pastoral regions exceeded those in traditional pastoral areas. ConclusionFrom 2018 to 2023, the incidence of brucellosis in Zhangjiakou City showed a declining trend, with significant spatial clustering observed across the city. It is recommended to intensify health education among males aged 40‒<60 years. Scientific livestock management practices should be promoted in non-pastoral and mixed areas, and cross-sectoral quarantine and joint prevention and control efforts should be strengthened as well.

OBJECTIVE: To evaluate the effect of biodegradable magnesium alloy materials in promoting tendon-bone healing during rotator cuff tear repair and to investigate their potential underlying biological mechanisms. METHODS: Forty-eight 8-week-old Sprague Dawley rats were taken and randomly divided into groups A, B, and C. Rotator cuff tear models were created and repaired using magnesium alloy sutures in group A and Vicryl Plus 4-0 absorbable sutures in group B, while only subcutaneous incisions and sutures were performed in group C. Organ samples of groups A and B were taken for HE staining at 1 and 2 weeks after operation to evaluate the safety of magnesium alloy, and specimens from the supraspinatus tendon and proximal humerus were harvested at 2, 4, 8, and 12 weeks after operation. The specimens were observed macroscopically at 4 and 12 weeks after operation. Biomechanical tests were performed at 4, 8, and 12 weeks to test the ultimate load and stiffness of the healing sites in groups A and B. At 2, 4, and 12 weeks, the specimens were subjected to the following tests: Micro-CT to evaluate the formation of bone tunnels in groups A and B, HE staining and Masson staining to observe the regeneration of fibrocartilage at the tendon-bone interface after decalcification and sectioning, and Goldner trichrome staining to evaluate the calcification. Immunohistochemical staining was performed to detect the expressions of angiogenic factors, including vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2), as well as osteogenic factors at the tendon-bone interface. Additionally, immunofluorescence staining was used to examine the expressions of Arginase 1 and Integrin beta-2 to assess M1 and M2 macrophage polarization at the tendon-bone interface. The role of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway in tendon-bone healing was further analyzed using real-time fluorescence quantitative PCR. RESULTS: Analysis of visceral sections revealed that magnesium ions released during the degradation of magnesium alloys did not cause significant toxic effects on organs such as the heart, liver, spleen, lungs, and kidneys, indicating good biosafety. Histological analysis further demonstrated that fibrocartilage regeneration at the tendon-bone interface in group A occurred earlier, and the amount of fibrocartilage was significantly greater compared to group B, suggesting a positive effect of magnesium alloy material on tendon-bone interface repair. Additionally, Micro-CT analysis results revealed that bone tunnel formation occurred more rapidly in group A compared to group B, further supporting the beneficial effect of magnesium alloy on bone healing. Biomechanical testing showed that the ultimate load in group A was consistently higher than in group B, and the stiffness of group A was also greater than that of group B at 4 weeks, indicating stronger tissue-carrying capacity following tendon-bone interface repair and highlighting the potential of magnesium alloy in enhancing tendon-bone healing. Immunohistochemical staining results indicated that the expressions of VEGF and BMP-2 were significantly upregulated during the early stages of healing, suggesting that magnesium alloy effectively promoted angiogenesis and bone formation, thereby accelerating the tendon-bone healing process. Immunofluorescence staining further revealed that magnesium ions exerted significant anti-inflammatory effects by regulating macrophage polarization, promoting their shift toward the M2 phenotype. Real-time fluorescence quantitative PCR results demonstrated that magnesium ions could facilitate tendon-bone healing by modulating the PI3K/AKT signaling pathway. CONCLUSION Biodegradable magnesium alloy material accelerated fibrocartilage regeneration and calcification at the tendon-bone interface in rat rotator cuff tear repair by regulating the PI3K/AKT signaling pathway, thereby significantly enhancing tendon-bone healing.
Animals ; Rotator Cuff Injuries/metabolism* ; Rats, Sprague-Dawley ; Signal Transduction ; Wound Healing/drug effects* ; Alloys/pharmacology* ; Rats ; Proto-Oncogene Proteins c-akt/metabolism* ; Rotator Cuff/metabolism* ; Macrophages/metabolism* ; Magnesium/pharmacology* ; Phosphatidylinositol 3-Kinases/metabolism* ; Vascular Endothelial Growth Factor A/metabolism* ; Male ; Biocompatible Materials ; Bone Morphogenetic Protein 2/metabolism*