ObjectiveTo explore the mechanism by which the Shenfu Xiongze prescription regulates autophagy in rats with myocardial remodeling through the adenosine monophosphate-activated protein kinase （AMPK）/mammalian target of rapamycin （mTOR） signaling pathway. MethodsA rat model of myocardial remodeling induced by isoprenaline （ISO） was established. Rats were divided into the blank group，the model group，the low-，medium-， and high-dose groups of Shenfu Xiongze prescription，and the captopril group， 6 rats in each group. Except for the blank group，the rat model of myocardial remodeling was established in the other groups by intraperitoneal injection of 2.5 mg·kg^-1 ISO for 3 consecutive weeks. At the same time of modeling， the low-，medium-， and high-dose groups of Shenfu Xiongze prescription were administered the corresponding doses of Shenfu Xiongze prescription solution （8.4，16.8，and 33.6 g·kg^-1），and the captopril group was administered captopril solution （25 mg·kg^-1）. As for the blank group and the model group， the same volume of normal saline was given. The treatment was continued for 3 weeks. Echocardiography was used to observe the cardiac structure and function，and the heart weight index was detected. Masson staining and hematoxylin-eosin （HE） staining were used to observe the pathological morphology changes of myocardial tissue. The levels of interleukin-6 （IL-6） and B-type natriuretic peptide （BNP） in serum were detected by enzyme-linked immunosorbent assay （ELISA）. The expression of type Ⅰ collagen （Collagen Ⅰ），type Ⅲ collagen （Collagen Ⅲ），and microtubule-associated protein 1 light chain 3 （LC3） proteins in myocardial tissue was determined by immunohistochemistry. Autophagy was observed by transmission electron microscopy. The mRNA expression of Collagen Ⅰ，Collagen Ⅲ，α-smooth muscle actin （α-SMA），LC3，yeast Atg6 homolog protein （Beclin-1），AMPK，and mTOR in myocardial tissue was detected by quantitative real-time polymerase chain reaction （real-time PCR）. The protein expression of Collagen Ⅰ，α-SMA，transforming growth factor-β₁ （TGF-β₁），LC3，Beclin-1，p62， phosphorylation（p）-AMPK，p-mTOR，AMPK，and mTOR was detected by Western blot. ResultsCompared with the normal group，rats in the model group exhibited significantly decreased values of ejection fraction （EF） and left ventricular fractional shortening （FS） （P<0.01）， significantly increased values of left ventricular end-diastolic diameter （LVIDd） and left ventricular end-systolic diameter （LVIDs） （P<0.01）. Additionally， the model group also showed increased degrees of inflammatory infiltration and fibrosis of myocardial tissue， significantly elevated levels of serum IL-6 and BNP （P<0.01）， significantly increased mRNA and protein levels of Collagen Ⅰ，Collagen Ⅲ，α-SMA，and mTOR （P<0.01），and markedly decreased mRNA and protein levels of LC3，Beclin-1，and AMPK （P<0.05，P<0.01）. Compared with the model group， the low-，medium-， and high-dose groups of Shenfu Xiongze prescription presented significantly elevated EF and FS values （P<0.01） and lowered LVIDd and LVIDs （P<0.05）. In these groups， the inflammation and fibrosis were alleviated significantly. They also exhibited decreased serum levels of IL-6 and BNP （P<0.01）， significantly reduced protein expression of Collagen Ⅰ， α-SMA， TGF-β₁， p62， and p-mTOR （P<0.01）， significantly decreased mRNA expression of Collagen Ⅰ， Collagen Ⅲ， α-SMA， and mTOR （P<0.01）， and significantly increased mRNA and protein levels of LC3， Beclin-1， and AMPK （P<0.05，P<0.01）. ConclusionThe Shenfu Xiongze prescription can improve the myocardial remodeling induced by ISO in rats by regulating the autophagy level，enhance cardiac function，and reduce inflammatory and fibrotic levels. This effect may be achieved through the AMPK/mTOR signaling pathway.

Pulmonary siderosis caused by iron and its compound dust is prone to misdiagnosis and underdiagnosis due to its insidious exposure pathways and non-specific imaging manifestations. This study analyzes the occupational histories and clinical data of six patients with occupational pulmonary siderosis diagnosed at Qingdao Central Hospital between January 2017 and December 2023, summarizes its characteristics, and evaluates the value of AI-assisted diagnosis. All six patients were male, with five being welders. The median dust exposure duration was 9.4 years, and the median latency period was 8.4 years. The main symptoms were chest tightness, cough, and shortness of breath. High-kilovolt chest radiographs were negative in four cases and showed thickened bronchovascular markings in two cases. High-resolution computed tomography (HRCT) revealed centrilobular nodules and tree-in-bud opacities in all cases. Pulmonary siderosis caused by iron and its compound dust is characterized by mild symptoms and a favorable prognosis. Comprehensive assessment and HRCT are crucial for early diagnosis. The development of AI models could enhance diagnostic recognition efficiency and promote precision diagnosis in the future.

Objective:To investigate the effects of baicalin on ferroptosis of mouse fibroblasts (Fbs) under high glucose treatment and its mechanism, and to provide a basis for the treatment of diabetic wounds.Methods:The study was an experimental study. Mouse Fbs were collected and divided into control group with conventional culture, high glucose group treated with glucose at final molarity of 30.0 mmol/L, and low baicalin group and high baicalin group pretreated with baicalin at final molarties of 5 and 10 μmol/L respectively and then treated as that in high glucose group. After 48 h of culture, the cell survival rate was detected by the cell counting kit-8, the reactive oxygen species level in cells was detected by the fluorescent probe method, the levels of malondialdehyde, glutathione, and ferrous ion in cells were detected by colorimetry, and the protein expression levels of solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) in cells and nuclear factor-erythroid 2-related factor 2 (Nrf2) in cytoplasm and nucleus were detected by Western blotting. Another batch of mouse Fbs were collected and divided into control group, high glucose group, high baicalin group, and high baicalin+ML385 group. The cells in the first three groups were treated as before, the cells in the last group were pretreated with baicalin and ML385 of Nrf2 inhibitor at final molarties of 10 μmol/L and then treated as that in high glucose group. After 48 h of culture, the protein expression levels of SLC7A11 and GPX4 in cells and the protein expression level of Nrf2 in cytoplasm and nucleus were detected as before. Except that the sample number in detecting SLC7A11 and GPX4 was 4, the sample number in detecting other indexes was 3.Results:After 48 h of culture, the cell survival rates in control group, high glucose group, low baicalin group, and high baicalin group were (100.0±10.7)%, (70.0±5.0)%, (80.9±3.2)%, and (91.4±1.9)%, respectively. Compared with those in control group, the cell survival rate, the glutathione level, and SLC7A11 and GPX4 protein expression levels in cells, and nuclear Nrf2 protein expression level were significantly decreased in high glucose group ( P<0.05), and the levels of reactive oxygen species, malondialdehyde, and ferrous ion in cells, and cytoplasmic Nrf2 protein expression level were significantly increased in high glucose group ( P<0.05). Compared with those in high glucose group, the cell survival rate, glutathione level, SLC7A11 and GPX4 protein expression levels in cells, and nuclear Nrf2 protein expression level in low baicalin group and high baicalin group were significantly increased ( P<0.05), the reactive oxygen species and ferrous ion levels in cells, and cytoplasmic Nrf2 protein expression level in low baicalin group and high baicalin group were significantly decreased ( P<0.05), and the malondialdehyde level in cells in high baicalin group was significantly decreased ( P<0.05). Compared with those in low baicalin group, the cell survival rate, glutathione level, SLC7A11 and GPX4 protein expression levels in cells, and nuclear Nrf2 protein expression level in high baicalin group were significantly increased ( P<0.05), and the reactive oxygen species, malondialdehyde, and ferrous ion levels in cells, and cytoplasmic Nrf2 protein expression level in high baicalin group were significantly decreased ( P<0.05). After 48 h of culture, compared with those in control group, the nuclear Nrf2 protein expression level and SLC7A11 and GPX4 protein expression levels in cells were significantly decreased ( P<0.05), and the cytoplasmic Nrf2 protein expression level was significantly increased in high glucose group ( P<0.05); compared with those in high glucose group, the cytoplasmic Nrf2 protein expression level was significantly decreased ( P<0.05), and the nuclear Nrf2 protein expression level and SLC7A11 and GPX4 protein expression levels in cells were significantly increased in high baicalin group ( P<0.05); compared with those in high baicalin group, the cytoplasmic Nrf2 protein expression level was significantly increased ( P<0.05), and the nuclear Nrf2 protein expression level and SLC7A11 and GPX4 protein expression levels in cells were significantly decreased in high baicalin+ML385 group ( P<0.05). Conclusions:Baicalin can inhibit the occurrence of ferroptosis in cells by activating the Nrf2 signaling pathway and up-regulating the expressions of proteins related to SLC7A11/GPX4 axis in Fbs in high glucose treatment, thus increasing the cell survival rate.

Objective:To discuss the ameliorative effect of total flavonoids from corn silk(TFCS)on kidney injury in the rats with urate nephropathy,and to clarify the possible mechanism.Methods:Sixty male Wistar rats were randomly divided into control group,model group,positive control group[benzbromarone(BZM)group,5 mg·kg-1·d-1],low dose of TFCS group(20 mg·kg-1·d-1),medium dose of TFCS group(40 mg·kg-1·d-1),and high dose of TFCS group(80 mg·kg-1·d-1),and there were 10 rats in each group.Except for control group,the rats in the other groups were administered potassium oxonate(350 mg·kg-1)and adenine(70 mg·kg-1)by gavage for 4 weeks to establish the hyperuricemic nephropthy models.The rats in different doses of TFCS groups were treated with TFCS for 2 weeks.Speckle blood flow imager was used to detect the renal blood perfusion of the rats in various groups and the kidney coefficients of the rats in various groups were caculated;HE staining and Masson staining were used to observe the pathomorphology and fibrosis degrees of kidney tissue of the rats in various groups and enzyme-linked immunosorbent assay(ELISA)method was used to detect the levels of uric acid(UA),creatinine(Cr),blood urea nitrogen(BUN),interleukin-6(IL-6),and tumor necrosis factor-α(TNF-α)in the serum and levels of β2-microglobulin(β2-MG)and microalbumin(ALB)in the urine of the rats in various groups;Western blotting method was used to detect the expression levels of urate transporter 1(URAT1),glucose transporter 9(GLUT9),and ATP-binding cassette transporter G2(ABCG2)proteins in kidney tissue of the rats in various groups.Results:Compared with control group,the renal blood perfusion volume of the rats in model group was significantly decreased(P<0.01).Compared with model group,the renal blood perfusion volumes of the rats in BZM group and low,medium,and high doses of TFCS groups were significantly increased(P<0.05 or P<0.01).Compared with control group,the kidney weight of the rats in model group was increased,with visible white granular spots on the surface,absence of blood color,and kidney volume was increased.Compared with model group,the kidney volumes of the rats in BZM group and medium and high doses of TFCS groups were decreased,with color tending toward that in control group,and the white granular spots on the surface were significantly reduced.Compared with model group,the kidney coefficients of the rats in BZM group and medium and high doses of TFCS groups were decreased(P<0.01).The HE staining results showed there were no abnormalities in kidney tissue structure in control group,while there were a small amount of brown-yellow urate crystal deposition and interstitial connective tissue hyperplasia in model group;compared with model group,the kidney tissue damage and inflammatory infiltration were alleviated to varying degrees in BZM group and different doses of TFCS groups.The Masson staining results revealed no obvious collagen fiber deposition in control group,whereas significant blue collagen fiber deposition in kidney tissue of the rats was found in model group,and the collagen volume fraction(CVF)was increased compared with control group(P<0.01);compared with model group,the CVFs of the rats in BZM group and different doses of TFCS groups were decreased(P<0.01).The ELISA results showed that compared with control group,the levels of UA,Cr,BUN,IL-6,and TNF-α in serum of the rats in model group were increased(P<0.01);compared with model group,the levels of UA,Cr,BUN,IL-6,and TNF-α in serum of the rats in BZM group and medium and high doses of TFCS groups were decreased(P<0.01).Compared with control group,the levels of β2-MG and ALB in urinary in model group were increased(P<0.01);compared with model group,the levels of β2-MG and ALB in urinary of the rats in different doses of TFCS groups were decreased(P<0.05 or P<0.01).The Western blotting results showed that compared with control group,the expression levels of URAT1 and GLUT9 proteins in kidney tissue of the rats in BZM group and model group were increased(P<0.01),while the expression level of ABCG2 protein was decreased(P<0.01).Compared with model group,the expression levels of URAT1 and GLUT9 proteins in kidney tissue of the rats in different doses of TFCS groups were decreased(P<0.05 or P<0.01),and the expression level of ABCG2 protein was increased(P<0.01).Conclusion:TFCS can significantly alleviate the kidney injury in the rats with urate nephropathy model,and its mechanism may be related to the downregulation of expression of URAT1 and GLUT9 proteins and upregulation of ABCG2 protein expression in kidney tissue.

Objective To explore the role and mechanism of warm malate ringer's solution(MR)in resuscitation of the lethal triad caused by severe trauma.Methods A rat model of severe trauma was established in SPF-grade SD rats(half male and half female,weighing 200～220 g)using combined multiple injuries and hemorrhagic shock,and the rats were randomly divided into 8 groups(n=8):Sham group,only arterial and venous catheterization;Trauma(Tra)groups with different time points(10,30,60,90,120,180 min)and a Trauma group that were observed without any treatment for 180 min after model establishment.The changes of activated clotting time(ACT),reaction time(R),maximum amplitude(MA),and rate of blood clot formation(Angle)at different time points were detected by using thromboelastography,and tail bleeding,core body temperature and arterial blood gas parameters,were also observed and detected.The plasma von Willebrand Factor(vWF)level,mitochondrial respiratory control ratio in pulmonary venous endothelium,and expression levels of vascular endothelial cadherin(VE-Cadherin),peroxisome proliferator activating receptor gamma coactivator 1α(PGC1α),dynamin-related protein 1(Drp1),p-Drp1,and mitofusin 2(Mfn2)were detected to evaluate the vascular endothelial injury and mitochondrial dysfunction.Another group of SD rats were randomly divided into severe trauma group(no treatment for 180 min after injury),and MR solution at room temperature and at 37 ℃ groups.MR solution at room temperature or at 37 ℃ was given to the rats using a medical blood transfusion apparatus at 60 min post-trauma.Above indicators were observed and detected to investigate the resuscitation effect of the MR solution.Results Compared with the Sham group,the severely traumatic rats at 180 min after injury had significantly prolonged ACT and R values(P＜0.05),shortened MA and decreased Angle values(P＜0.05),extended tail bleeding time(P＜0.05),lower partial pressure of carbon dioxide(PCO2)and HCO3-and base excess(BE)levels(P＜0.05),and continuously increasing K+(P＜0.05)and decreasing Na+(P＜0.05)and Ca2+levels(P＜0.05).Additionally,plasma vWF level(P＜0.05)and protein levels of VE-cadherin,PGC1α and Mfn2 in pulmonary vein endothelium were significantly reduced(P＜0.05),the expression of p-Drp1 was enhanced and the mitochondrial respiration control rate was declined in the rats at 180 min after injury(P＜0.05).MR solution resuscitation shortened tail bleeding time(P＜0.05),increased core body temperature(P＜0.05),elevated plasma vWF level(P＜0.05),increased protein levels of VE-cadherin,PGC1α and Mfn2(P＜0.05),and decreased that of p-Drp1 protein expression(P＜0.05)when compared with the rats at 180 min after severe traumatic injury.The above effects were more significant in the rats infused with the solution at 37 ℃ than those at room temperature.Conclusion Warm MR solution significantly improves the lethal triad in rats after severe trauma,which may be associated with its improving mitochondrial function and attenuating vascular endothelial damage.

Objective:To investigate the clinicopathological characteristics and prognostic influencing factors in young breast cancer patients.Methods:A retrospective case series study was conducted. The clinical data of 408 young patients with breast cancer in the Fifth Medical Center of Chinese PLA General Hospital from January 2005 to December 2020 were retrospectively analyzed. The clinical characteristics and prognostic influencing factors of patients were observed. The Kaplan-Meier method was used to analyze overall survival (OS) and disease-free survival (DFS) of patients. Univariate analysis of prognostic factors was conducted by using the log-rank test, and multivariate analysis was performed by using Cox proportional risk model.Results:The median age [ M ( Q1, Q3)] of 408 young female patients with breast cancer was 36 (33, 39) years; the 5-year OS and 5-year DFS rates were 89.9%, 84.0% of 387 breast cancer patients in early and middle stage (except for stage Ⅳ). There were statistically significant differences in the 5-year OS and 5-year DFS rates (excluding stage Ⅳ of DFS) of patients with different clinical staging and molecular subtypes (all P < 0.05). The differences were statistically significant in the 5-year DFS rate of patients with different pathological types and histological grades (all P < 0.05). There were no statistically significant differences in the 5-year OS and DFS rates between the patients receiving breast-conserving surgery or mastectomy (all P > 0.05). The results of multivariate Cox regression analysis indicated that clinical staging ( HR = 3.121, 95% CI: 2.301-4.233, P < 0.001) and molecular classification ( HR = 1.441, 95% CI: 1.126-1.845, P = 0.004) were independent prognostic factors for OS. Additionally, clinical staging ( HR = 3.001, 95% CI: 2.174-4.141, P < 0.001) was identified as an independent prognostic factor for DFS. Conclusions:The prognosis of young breast cancer patients is closely related to clinical staging and molecular subtype. The later the clinical stage is, the poorer prognosis is. Luminal-type breast cancer has a better prognosis than other subtypes. For early-stage breast cancer patients who meet the criteria for breast-conserving surgery, breast-conserving surgery is the first-choice alternative.

Objective:To investigate the immunological mechanism by which grifola frondosa extract improves colonic tissue inflammation in rats with ulcerative colitis(UC)through the sphingosine kinase 1(SPHK1)/sphingosine-1-phosphate(S1P)signaling pathway.Methods:Forty male SD rats were randomly divided into five groups:blank group,model group,sulfasalazine treatment group(SASP group),grifola frondosa extract treatment group(GF group),and sulfasalazine combined with grifola frondosa extract treatment group(SASP+GF group).UC model was established using a 3%dextran sulfate sodium(DSS)free drinking method.After one week,each treatment group received sulfasalazine 0.3 g/(kg·d),grifola frondosa extract 10 mg/(kg·d),and combination of both drugs by gavage.During the experiment,the general condition of the rats was observed,the disease activity index(DAI)score was re-corded and the protein content and positive expression levels of SPHK1,S1P,tumor necrosis factor receptor-associated factor 2(TRAF2)and TNF-α in rat colon tissue were detected by immunohistochemistry.mRNA and protein expression levels of SPHK1,S1P,TRAF2 and TNF-α in rat colon tissue were measured by RT-qPCR and Western blot.Results:Compared with the blank group,the general condition of the model group rats were poor,the DAI score was significantly increased,and the protein positive expres-sion,mRNA and protein expression levels of SPHK1,S1P,TRAF2 and TNF-α in colon tissue were significantly increased(P<0.01).Compared with the model group,the general condition of the rats in each treatment group improved significantly,the DAI score was decreased(P<0.01),and the positive expression of each target protein was significantly reduced(P<0.01),especially in the GF group and SASP+GF group;the mRNA and protein expression levels of SPHK1 and TRAF2 were reduced to varying degrees(P<0.01 or P<0.05),while the mRNA and protein expression levels of S1P and TNF-α only decreased significantly in the GF group and SASP+GF group(P<0.01).Compared with the SASP group,the GF group only showed a decrease in SPHK1 protein expression,TNF-α mRNA,and protein expression levels,while the SASP+GF group showed significant reductions in all targets(P<0.01 or P<0.05).Compared with the GF group,the SASP+GF group showed significant reductions in SPHK1 protein positive expression and content,S1P mRNA expression levels,and TNF-α protein content(P<0.05 or P<0.01).Conclusion:Grifola frondosa extract may alleviate co-lonic tissue inflammation in rats with UC by inhibiting the activation of the SPHK1/S1P pathway,restoring intestinal mucosal barrier function,and improving symptoms of UC.

Pulmonary siderosis caused by iron and its compound dust is prone to misdiagnosis and underdiagnosis due to its insidious exposure pathways and non-specific imaging manifestations. This study analyzes the occupational histories and clinical data of six patients with occupational pulmonary siderosis diagnosed at Qingdao Central Hospital between January 2017 and December 2023, summarizes its characteristics, and evaluates the value of AI-assisted diagnosis. All six patients were male, with five being welders. The median dust exposure duration was 9.4 years, and the median latency period was 8.4 years. The main symptoms were chest tightness, cough, and shortness of breath. High-kilovolt chest radiographs were negative in four cases and showed thickened bronchovascular markings in two cases. High-resolution computed tomography (HRCT) revealed centrilobular nodules and tree-in-bud opacities in all cases. Pulmonary siderosis caused by iron and its compound dust is characterized by mild symptoms and a favorable prognosis. Comprehensive assessment and HRCT are crucial for early diagnosis. The development of AI models could enhance diagnostic recognition efficiency and promote precision diagnosis in the future.

Objective:To investigate the role of the structural gene vgrG of the type Ⅵ secretion system (T6SS) of Klebsiella pneumoniae ( Kpn), and evaluate the growth ability in vitro and pathogenicity of the bacteria after vgrG was deleted. Methods:Using sequences published by the National Center for Biotechnology Information (NCBI), primers were designed to amplify the upstream and downstream homology arms of vgrG via PCR. These fragments were cloned into the vector pKO3-Km after overlapping, the recombinant vector pKO3-Km- vgrG was transferred into Kpn competent cells, and the vgrG deletion strain Δ vgrG was obtained through homologous recombination. The vgrG promoter with the complete gene fragment was amplify by PCR and cloned into the pBAD33 vector. The pBAD33- vgrG was then transferred into Δ vgrG competent cells to obtain the complemented strain CΔ vgrG. The wild-type strain (WT), Δ vgrG strain and CΔ vgrG strain were cultured in LB (Luria-Bertani) liquid medium to compare growth rates. Adhesion to human lung epithelial A549 cells and intracellular survival in macrophages Raw264.7 cells were assessed. In vivo experiments included mouse survival analysis ( n=10) and lung bacterial load quantification ( n=6). Statistical comparisons were performed using the Student t-test. Results:The Δ vgrG strain was obtained through homologous recombination. It was identified by specific primers that compared with the WT strain, the complete vgrG fragment (2 487 bp) was deleted. On this basis, the CΔ vgrG strain was obtained. Deletion of vgrG did not significantly affect Kpn growth in vitro growth ability of bacteria before on after Kpn deleted vgrG [(1.40±0.10) vs (1.20±0.30), t=0.63, P>0.05]. The viscosity of WT strain was significantly higher than that of the Δ vgrG strain [(0.96±0.04) vs (0.38±0.05), t=9.72, P<0.05], the viscosity of the CΔ vgrG strain was also significantly higher than that of the Δ vgrG strain ( P<0.05). At the cellular level, the amount of adherent bacteria of the WT strain to A549 cells was significantly greater than that of the Δ vgrG strain [(5 367.00±318.00) CFU vs (4 067.00±88.19) CFU, t=3.94, P<0.05], the amount of adherent bacteria of CΔ vgrG strain was also significantly higher than that of Δ vgrG strain ( P<0.05). After 12 h infection, the WT strain survival rate in macrophages was significantly higher than that of the Δ vgrG strain[(69.00±1.00)% vs (47.50±2.50)%, t=7.99, P<0.05]. At the animal level, the survival rate of WT strain group after lethal dose infection of mice was significantly lower than that of Δ vgrG strain group [(16.67±8.82)% vs (53.33±6.67)%, t=3.32, P<0.05]; mice infected with semi-lethal dose and the number of bacteria load in the lungs of WT strain group was significantly higher than that of the Δ vgrG strain group[ (4.97±0.06) lg CFU/g vs (4.05 ±0.04) lg CFU/g, t=12.27, P<0.01], the amount of bacteria in the lungs of mice in CΔ vgrG strain group was also significantly higher than that in Δ vgrG strain group ( P<0.01). Conclusions:The vgrG gene does not affect the growth of Kpn in vitro, but it is involved in the adhesion of Kpn to epithelial cells, resistance to macrophage killing and pathogenicity to mice.

Objective:To investigate the role of the structural gene vgrG of the type Ⅵ secretion system (T6SS) of Klebsiella pneumoniae ( Kpn), and evaluate the growth ability in vitro and pathogenicity of the bacteria after vgrG was deleted. Methods:Using sequences published by the National Center for Biotechnology Information (NCBI), primers were designed to amplify the upstream and downstream homology arms of vgrG via PCR. These fragments were cloned into the vector pKO3-Km after overlapping, the recombinant vector pKO3-Km- vgrG was transferred into Kpn competent cells, and the vgrG deletion strain Δ vgrG was obtained through homologous recombination. The vgrG promoter with the complete gene fragment was amplify by PCR and cloned into the pBAD33 vector. The pBAD33- vgrG was then transferred into Δ vgrG competent cells to obtain the complemented strain CΔ vgrG. The wild-type strain (WT), Δ vgrG strain and CΔ vgrG strain were cultured in LB (Luria-Bertani) liquid medium to compare growth rates. Adhesion to human lung epithelial A549 cells and intracellular survival in macrophages Raw264.7 cells were assessed. In vivo experiments included mouse survival analysis ( n=10) and lung bacterial load quantification ( n=6). Statistical comparisons were performed using the Student t-test. Results:The Δ vgrG strain was obtained through homologous recombination. It was identified by specific primers that compared with the WT strain, the complete vgrG fragment (2 487 bp) was deleted. On this basis, the CΔ vgrG strain was obtained. Deletion of vgrG did not significantly affect Kpn growth in vitro growth ability of bacteria before on after Kpn deleted vgrG [(1.40±0.10) vs (1.20±0.30), t=0.63, P>0.05]. The viscosity of WT strain was significantly higher than that of the Δ vgrG strain [(0.96±0.04) vs (0.38±0.05), t=9.72, P<0.05], the viscosity of the CΔ vgrG strain was also significantly higher than that of the Δ vgrG strain ( P<0.05). At the cellular level, the amount of adherent bacteria of the WT strain to A549 cells was significantly greater than that of the Δ vgrG strain [(5 367.00±318.00) CFU vs (4 067.00±88.19) CFU, t=3.94, P<0.05], the amount of adherent bacteria of CΔ vgrG strain was also significantly higher than that of Δ vgrG strain ( P<0.05). After 12 h infection, the WT strain survival rate in macrophages was significantly higher than that of the Δ vgrG strain[(69.00±1.00)% vs (47.50±2.50)%, t=7.99, P<0.05]. At the animal level, the survival rate of WT strain group after lethal dose infection of mice was significantly lower than that of Δ vgrG strain group [(16.67±8.82)% vs (53.33±6.67)%, t=3.32, P<0.05]; mice infected with semi-lethal dose and the number of bacteria load in the lungs of WT strain group was significantly higher than that of the Δ vgrG strain group[ (4.97±0.06) lg CFU/g vs (4.05 ±0.04) lg CFU/g, t=12.27, P<0.01], the amount of bacteria in the lungs of mice in CΔ vgrG strain group was also significantly higher than that in Δ vgrG strain group ( P<0.01). Conclusions:The vgrG gene does not affect the growth of Kpn in vitro, but it is involved in the adhesion of Kpn to epithelial cells, resistance to macrophage killing and pathogenicity to mice.