BACKGROUND:Studies have shown that metformin has anti-inflammatory,anti-tumor,anti-aging and vasoprotective effects,and can inhibit the progression of osteoarthritis,but its specific mechanism of action remains unclear. OBJECTIVE:To investigate the mechanism of metformin on cartilage protection in a rat model of osteoarthritis. METHODS:Forty male Sprague-Dawley rats were randomly divided into four groups(n=10 per group):blank,control,sham-operated,and metformin groups.The blank group did not undergo any surgery.In the sham-operated group,the joint cavity was exposed.In the model group and the metformin group,the modified Hulth method was used to establish the osteoarthritis model.At 1 day after modeling,the rats in the metformin group were given 200 mg/kg/d metformin by gavage,and the model,blank,and sham-operated groups were given normal saline by gavage.Administration in each group was given for 4 weeks consecutively.Hematoxylin-eosin staining,toluidine blue staining,and safranin O-fast green staining were used to observe the morphological structure of rat knee joints.Immunohistochemical staining and western blot were used to detect the protein expression of SOX9,type Ⅱ collagen,a disintegrin and metalloproteinase with thrombospondin motifs 5(ADAMTS5),Beclin1,P62,phosphatidylinositol 3-kinase(PI3K),p-PI3K,protein kinase B(AKT),p-AKT,mammalian target of rapamycin(Mtor),and p-Mtor in rat cartilage tissue. RESULTS AND CONCLUSION:The results of hematoxylin-eosin,toluidine blue and safranin O-fast green staining showed smooth cartilage surface of the knee joints and normal histomorphology in the blank group and the sham-operated group,while in the model group,there was irregular cartilage surface of the knee joint and cartilage damage,with a decrease in the number of chondrocytes and the content of proteoglycans in the cartilage matrix.In the metformin group,there was a significant improvement in the damage to the structure of the cartilage in the knee joints of the rats,and the cartilage surface tended to be smooth,with an increase in the number of chondrocytes and the content of proteoglycans in the cartilage matrix.Immunohistochemistry staining and western blot results showed that compared with the control and sham-operated groups,the expression of SOX9,type Ⅱ collagen,and Beclin1 proteins in the cartilage tissue of rats in the model group was significantly decreased(P<0.05).Conversely,the expression of ADAMTS5,P62,as well as p-PI3K,p-AKT,and p-Mtor proteins was significantly increased(P<0.05).Furthermore,compared with the model group,the expression of SOX9,type Ⅱ collagen,and Beclin1 proteins in the cartilage tissue of rats in the metformin group was significantly increased(P<0.05),while the expression of ADAMTS5,P62,as well as p-PI3K,p-AKT,and p-Mtor proteins was significantly decreased(P<0.05).To conclude,Metformin can improve the autophagy activity of chondrocytes and reduce the degradation of cartilage matrix in osteoarthritis rats by inhibiting the activation of PI3K/AKT/Mtor signaling pathway,thus exerting a protective effect on articular cartilage.

Objective To summarize the epidemiological and clinical features of infectious diseases of the central nervous system(CNS)by a single-center analysis.Methods A retrospective analysis was conducted on the data of 1247 cases of CNS infectious diseases diagnosed and treated in the First Medical Center of PLA General Hospital from 2001 to 2020.Results The data for this group of CNS infectious diseases by disease type in descending order of number of cases were viruses 743(59.6％),Mycobacterium tuberculosis 249(20.0％),other bacteria 150(12.0％),fungi 68(5.5％),parasites 18(1.4％),Treponema pallidum 18(1.4％)and rickettsia 1(0.1％).The number of cases increased by 177 cases(33.1％)in the latter 10 years compared to the previous 10 years(P<0.05).No significant difference in seasonal distribution pattern of data between disease types(P>0.05).Male to female ratio is 1.87︰1,mostly under 60 years of age.Viruses are more likely to infect students,most often at university/college level and above,farmers are overrepresented among bacteria and Mycobacterium tuberculosis,and more infections of Treponema pallidum in workers.CNS infectious diseases are characterized by fever,headache and signs of meningeal irritation,with the adductor nerve being the more commonly involved cranial nerve.Matagenomic next-generation sequencing improves clinical diagnostic capabilities.The median hospital days for CNS infectious diseases are 18.00(11.00,27.00)and median hospital costs are ￥29,500(￥16,000,￥59,200).The mortality rate from CNS infectious diseases is 1.6％.Conclusions The incidence of CNS infectious diseases is increasing last ten years,with complex clinical presentation,severe symptoms and poor prognosis.Early and accurate diagnosis and standardized clinical treatment can significantly reduce the morbidity and mortality rate and ease the burden of disease.

Objective This study aimed to investigate the potential relationship between urinary metals copper (Cu), arsenic (As), strontium (Sr), barium (Ba), iron (Fe), lead (Pb) and manganese (Mn) and grip strength. Methods We used linear regression models, quantile g-computation and Bayesian kernel machine regression (BKMR) to assess the relationship between metals and grip strength.Results In the multimetal linear regression, Cu (β=-2.119), As (β=-1.318), Sr (β=-2.480), Ba (β=0.781), Fe (β= 1.130) and Mn (β=-0.404) were significantly correlated with grip strength (P < 0.05). The results of the quantile g-computation showed that the risk of occurrence of grip strength reduction was -1.007 (95％ confidence interval:-1.362, -0.652; P < 0.001) when each quartile of the mixture of the seven metals was increased. Bayesian kernel function regression model analysis showed that mixtures of the seven metals had a negative overall effect on grip strength, with Cu, As and Sr being negatively associated with grip strength levels. In the total population, potential interactions were observed between As and Mn and between Cu and Mn (Pinteractions of 0.003 and 0.018, respectively).Conclusion In summary, this study suggests that combined exposure to metal mixtures is negatively associated with grip strength. Cu, Sr and As were negatively correlated with grip strength levels, and there were potential interactions between As and Mn and between Cu and Mn.

Programmed cell death 1 ligand 1 (PD-L1) is an important immunosuppressive molecule, which inhibits the function of T cells and other immune cells by binding to the receptor programmed cell death-1. The PD-L1 expression disorder plays an important role in the occurrence, development, and treatment of sepsis or other inflammatory diseases, and has become an important target for the treatment of these diseases. Mesenchymal stem cells (MSCs) are a kind of pluripotent stem cells with multiple differentiation potential. In recent years, MSCs have been found to have a strong immunosuppressive ability and are used to treat various inflammatory insults caused by hyperimmune diseases. Moreover, PD-L1 is deeply involved in the immunosuppressive events of MSCs and plays an important role in the treatment of various diseases. In this review, we will summarize the main regulatory mechanism of PD-L1 expression, and discuss various biological functions of PD-L1 in the immune regulation of MSCs.

Surgery is an important treatment for the anterior mediastinal disease. With the rapid development of minimally invasive techniques, complete resection of the lesion in most patients with thymic disease can be achieved through thoracoscopic surgery. Practice has proved that the three-port resection of anterior mediastinal thymus disease via the subxiphoid approach is an ideal surgical method for the treatment of anterior mediastinal thymic tumors at present, which has strong popularization and popularity and can benefit the patients. The procedure focuses primarily on the anterior and upper mediastinum and can thoroughly expose the anatomy of the mediastinum and both sides, with minimal intraoperative bleeding, high safety, minimal trauma and postoperative pain, and a short hospital stay. It has clear advantages over conventional thoracic open-heart surgery and transversal resection. However, the surgical approach and field of view, and intraoperative precautions of this procedure are completely different from those of previous thoracoscopic procedures, and from the subxiphoid single-port approach adopted by other centers. Based on 10 years of surgical experience at our center, a modular mode of surgical operation has been developed and its procedure has been standardized. This paper will share and discuss relevant operational points and experiences.

Objective To explore the toxicity of Polygonum multiflorum alcohol extract on 3D hepatospheres.Methods Variations in culture conditions and cell ratios were implemented,followed by the assessment of cell sphere diameter,density,and roundness,aiming to explore the optimal culture conditions.The 3D hepatocyte spheres were divided into control group and experimental-L,-M,-H groups.The experimental-L,-M,-H groups were treated with 0.25,1.00 and 2.50 mg·mL-1 Polygounm multiforum alcohol extract,and the control group was given the same amount of culture medium.The cell viability of the cell spheroids was tested by CellTiter-Glo reagent,the expression level of liver function related genes was detected by fluorescent quantitative polymerase chain reaction(RT-qRCR).The toxicity of cell spheres was detected by double fluorescent staining of living and dead cells.Results The ideal culture condition of cell sphere was 500 cells per micropore,and the cell ratio was HepG2-Huvec-LX-2=8∶1∶1.It displayed the values of 0.91±0.07 for circularity,0.91±0.02 for firmness,1.12±0.14 for aspect ratio,and(170.97±14.79)μm for diameter.On the 3rd,7th,10th and 14th days,the expression levels of albumin(ALB)mRNA were 1.00±0.02,0.96±0.02,0.54±0.07,0.52±0.07,and the expression levels of cytochrome P450 1A2(CYP1A2)mRNA were 1.00±0.10,2.15±0.16,2.45±0.33,1.30±0.03,respectively.The expression levels of multidrug resistance protein 2(MPR2)in the control group and the experimental-L,-M,-H groups were 1.00±0.31,1.38±0.24,1.48±0.06 and 1.90±0.08,respectively;spheroid viability were(98.19±0.49)％,(88.53±0.90)％,(71.60±2.91)％and(56.65±5.41)％.There were statistically significant differences in the above indexes between the experimental-L,-M,-H groups and the control group(all P＜0.05).Conclusion The established hepatocyte sphere co-culture model showed varying degrees of expression of phase Ⅰ/Ⅱ drug metabolism enzymes,transporters,and liver cell specific marker molecule albumin and can be used to evaluate the toxicity of multiflorum multiflorum,which provides further reference for the clinical application of multiflorum multiflorum.

Objective To evaluate the bioequivalence of a single oral dose of ritonavir in fasted and fed conditions in healthy Chinese adult subjects with the test and reference formulations.Methods A single-center,open-label,randomized,single-dose,two-periods,two-sequence crossover design was used,and 64 subjects were enrolled in both the fasted and fed groups.The subjects received 100 mg of the test preparation or reference preparation orally per cycle,and the drug concentration of ritonavir in plasma was detected using the high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method.Pharmacokinetic parameters were estimated by a non-compartment model,and SAS 9.4 software was used for statistical analysis.Results Arithmetic mean values of the main pharmacokinetic parameters of the subject formulation of ritonavir tablets and the reference formulation in the fasting group:Cmax were(791.90±400.20)and(809.60±449.14)ng·mL-1;AUC0_t were(6 072.61±2 631.98)and(6 296.30±3 388.95)ng·h·mL-1;AUC0-∞ were(6 129.59±2 655.57)and(6 347.26±3 434.12)ng·h·mL-1,respectively.Arithmetic mean values of the main pharmacokinetic parameters of the subject formulation of ritonavir tablets and the reference formulation in the fed group:Cmax were(512.37±233.60)and(521.74±223.87)ng·mL-1;AUC0_t were(4 203.43±2 221.33)and(4 200.13±1 993.50)ng·h·mL-1;AUC0_∞ were(4 259.21±2 266.88)and(4 259.63±2 044.12)ng·h·mL-1.The 90％confidence intervals for the geometric mean ratios of Cmax,AUC0_t and AUC0_∞ of the prototype drug ritonavir in plasma after oral administration of 100 mg of the test and reference formulations of ritonavir tablets under fasting and fed conditions fell within the 80.00％to 125.00％equivalence interval.Conclusion The test and reference formulations of ritonavir tablets were bioequivalent under fasting and postprandial conditions.

Objective To observe the intervention effect of hypericin(HYP)on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced Parkinson's disease(PD)mice model and its mechanism.Methods Thirty C57BL/6 mice were randomly divided into normal,model and experimental groups with 10 mice per group.PD mouse model was established after 7 days of intraperitoneal injection of MPTP,and drug intervention was carried out from the first day of modeling.Normal group and model group were intraperitoneally injected with 500 μL·kg·d-1 0.9％NaCl.The experimental group was intraperitoneally injected with 25 mg·kg·d-1 HYP.The three groups of rats were given the drug once each time for 14 days.The expression levels of tyrosine hydroxylase(TH),Nod-like receptor thermal protein domain protein 3(NLRP3)and ionized calcium binding adapter molecule 1(Iba1)in the striatum of nigra were detected by Western blot.Results The climbing time of normal,model and experimental groups was(5.35±0.43),(9.71±1.19)and(8.07±0.34)s;suspension scores were(2.92±0.15),(1.38±0.28)and(1.96±0.28)points;the relative expression levels of TH protein were 1.04±0.06,0.51±0.09 and 0.75±0.07;the relative expression levels of NLRP3 protein were 0.51±0.03,1.00±0.04 and 0.77±0.06;the relative expression levels of Iba1 protein were 0.68±0.10,1.30±0.28 and 0.89±0.05,respectively.The above indexes in the model group were statistically significant compared with the experimental group and the normal group(all P＜0.01).Conclusion HYP plays a therapeutic role in PD by inhibiting the expression of NLRP3 inflammasome in PD mice.

Purpose::Ischemia and hypoxia are the main factors limiting limb replantation and transplantation. Static cold storage (SCS), a common preservation method for tissues and organs, can only prolong limb ischemia time to 4 - 6 h. The normothermic machine perfusion (NMP) is a promising method for the preservation of tissues and organs, which can extend the preservation time in vitro by providing continuous oxygen and nutrients. This study aimed to evaluate the difference in the efficacy of the 2 limb preservation methods. Methods::The 6 forelimbs from beagle dogs were divided into 2 groups. In the SCS group ( n = 3), the limbs were preserved in a sterile refrigerator at 4 °C for 24 h, and in the NMP group ( n = 3), the perfusate prepared with autologous blood was used for the oxygenated machine perfusion at physiological temperature for 24 h, and the solution was changed every 6 h. The effects of limb storage were evaluated by weight gain, perfusate biochemical analysis, enzyme-linked immunosorbent assay, and histological analysis. All statistical analyses and graphs were performed using GraphPad Prism 9.0 one-way or two-way analysis of variance. The p value of less than 0.05 was considered to indicate statistical significance. Results::In the NMP group, the weight gained percentage was 11.72% ± 4.06%; the hypoxia-inducible factor-1α contents showed no significant changes; the shape of muscle fibers was normal; the gap between muscle fibers slightly increased, showing the intercellular distance of (30.19 ± 2.83) μm; and the vascular α-smooth muscle actin (α-SMA) contents were lower than those in the normal blood vessels. The creatine kinase level in the perfusate of the NMP group increased from the beginning of perfusion, decreased after each perfusate change, and remained stable at the end of perfusion showing a peak level of 4097.6 U/L. The lactate dehydrogenase level of the NMP group increased near the end of perfusion and reached the peak level of 374.4 U/L. In the SCS group, the percentage of weight gain was 0.18% ± 0.10%, and the contents of hypoxia-inducible factor-1α increased gradually and reached the maximum level of (164.85 ± 20.75) pg/mL at the end of the experiment. The muscle fibers lost their normal shape and the gap between muscle fibers increased, showing an intercellular distance of (41.66 ± 5.38) μm. The contents of vascular α-SMA were much lower in the SCS group as compared to normal blood vessels.Conclusions::NMP caused lesser muscle damage and contained more vascular α-SMA as compared to SCS. This study demonstrated that NMP of the amputated limb with perfusate solution based on autologous blood could maintain the physiological activities of the limb for at least 24 h.

Objective:To establish a mesenchymal stem cell(MSC)-based in vitro cell model for the evaluation of mouse bone marrow acute graft-versus-host disease(aGVHD).Methods:Female C57BL/6N mice aged 6-8 weeks were used as bone marrow and lymphocyte donors,and female BALB/c mice aged 6-8 weeks were used as aGVHD recipients.The recipient mouse received a lethal dose(8.0 Gy,72.76 cGy/min)of total body γ irradiation,and injected with donor mouse derived bone marrow cells(1× 107/mouse)in 6-8 hours post irradiation to establish a bone marrow transplantation(BMT)mouse model(n=20).In addition,the recipient mice received a lethal dose(8.0 Gy,72.76 cGy/min)of total body γ irradiation,and injected with donor mouse derived bone marrow cells(1 × 107/mouse)and spleen lymphocytes(2 × 106/mouse)in 6-8 hours post irradiation to establish a mouse aGVHD model(n=20).On the day 7 after modeling,the recipient mice were anesthetized and the blood was harvested post eyeball enucleation.The serum was collected by centrifugation.Mouse MSCs were isolated and cultured with the addition of 2％,5％,and 10％recipient serum from BMT group or aGVHD group respectively.The colony-forming unit-fibroblast(CFU-F)experiment was performed to evaluate the potential effects of serums on the self-renewal ability of MSC.The expression of CD29 and CD105 of MSC was evaluated by immunofluorescence staining.In addition,the expression of self-renewal-related genes including Oct-4,Sox-2,and Nanog in MSC was detected by real-time fluorescence quantitative PCR(RT-qPCR).Results:We successfully established an in vitro cell model that could mimic the bone marrow microenvironment damage of the mouse with aGVHD.CFU-F assay showed that,on day 7 after the culture,compared with the BMT group,MSC colony formation ability of aGVHD serum concentrations groups of 2％and 5％was significantly reduced(P＜0.05);after the culture,at day 14,compared with the BMT group,MSC colony formation ability in different aGVHD serum concentration was significantly reduced(P＜0.05).The immunofluorescence staining showed that,compared with the BMT group,the proportion of MSC surface molecules CD29+and CD 105+cells was significantly dereased in the aGVHD serum concentration group(P＜0.05),the most significant difference was at a serum concentration of 10％(P＜0.001,P＜0.01).The results of RT-qPCR detection showed that the expression of the MSC self-renewal-related genes Oct-4,Sox-2,and Nanog was decreased,the most significant difference was observed at an aGVHD serum concentration of 10％(P＜0.01,P＜0.001,P＜0.001).Conclusion:By co-culturing different concentrations of mouse aGVHD serum and mouse MSC,we found that the addition of mouse aGVHD serum at different concentrations impaired the MSC self-renewal ability,which providing a new tool for the field of aGVHD bone marrow microenvironment damage.