LIU Wansu， as the foremost of the four great masters of the Jin-Yuan period， established the "theory of fire-heat'' and extended the fire-heat pathogenesis framework to the field of stroke， thereby forming the theory of ''fire-heat inducing stroke''. This achieved a paradigmatic shift in stroke etiology from ''exogenous wind inducing stroke'' to ''fire-heat inducing stroke''. This paper systematically reviews the developmental trajectory of LIU Wansu's ''fire-heat inducing stroke'' theory and explores the social background， academic origins， and core connotations of its theoretical construction. The study found that， based on the ''Nineteen Pathomechanisms'' in the Huangdi's Internal Classic （Huang Di Nei Jing） and combined with clinical practice， LIU Wansu proposed that fire-heat is the fundamental cause of stroke， and that the Six Climatic Factors and the Five Zhi-Emotions can all transform into fire. He further constructed a stratified syndrome differentiation and therapeutic system centered on clearing heat and purging fire， emphasizing differentiated treatment of exterior and interior syndromes， Six Meridians syndrome differentiation， and seasonally adjusted medication. This theory not only resolved the diagnostic and therapeutic dilemmas of febrile epidemic diseases during the Jin-Yuan period， but also exerted a profound influence on later physicians such as ZHANG Zihe and ZHU Danxi， thereby promoting the pluralistic development of stroke theory in traditional Chinese medicine （TCM）. Modern pharmacological research provides solid scientific evidence， confirming that the ''fire-heat'' pathological state is highly associated with key mechanisms such as excessive inflammatory responses， oxidative stress， and excitatory amino acid toxicity following cerebral ischemia. Heat-clearing and fire-purging prescriptions and agents， such as Huanglian Jiedu Tang and baicalin， can exert multi-target neuroprotective effects by regulating inflammatory signaling， enhancing antioxidant enzyme activity， and balancing neurotransmitters. This not only verifies the scientific basis of the ''fire-heat inducing stroke'' theory from a modern biological perspective but also provides conclusive evidence for the clinical application of heat-clearing and fire-purging therapy. LIU Wansu's ''fire-heat inducing stroke'' theory represents a major milestone in the historical understanding of stroke pathogenesis， and its academically transitional insights continue to hold core guiding value for the pattern identification and treatment of ischemic stroke today.

LIU Wansu， as the foremost of the four great masters of the Jin-Yuan period， established the "theory of fire-heat'' and extended the fire-heat pathogenesis framework to the field of stroke， thereby forming the theory of ''fire-heat inducing stroke''. This achieved a paradigmatic shift in stroke etiology from ''exogenous wind inducing stroke'' to ''fire-heat inducing stroke''. This paper systematically reviews the developmental trajectory of LIU Wansu's ''fire-heat inducing stroke'' theory and explores the social background， academic origins， and core connotations of its theoretical construction. The study found that， based on the ''Nineteen Pathomechanisms'' in the Huangdi's Internal Classic （Huang Di Nei Jing） and combined with clinical practice， LIU Wansu proposed that fire-heat is the fundamental cause of stroke， and that the Six Climatic Factors and the Five Zhi-Emotions can all transform into fire. He further constructed a stratified syndrome differentiation and therapeutic system centered on clearing heat and purging fire， emphasizing differentiated treatment of exterior and interior syndromes， Six Meridians syndrome differentiation， and seasonally adjusted medication. This theory not only resolved the diagnostic and therapeutic dilemmas of febrile epidemic diseases during the Jin-Yuan period， but also exerted a profound influence on later physicians such as ZHANG Zihe and ZHU Danxi， thereby promoting the pluralistic development of stroke theory in traditional Chinese medicine （TCM）. Modern pharmacological research provides solid scientific evidence， confirming that the ''fire-heat'' pathological state is highly associated with key mechanisms such as excessive inflammatory responses， oxidative stress， and excitatory amino acid toxicity following cerebral ischemia. Heat-clearing and fire-purging prescriptions and agents， such as Huanglian Jiedu Tang and baicalin， can exert multi-target neuroprotective effects by regulating inflammatory signaling， enhancing antioxidant enzyme activity， and balancing neurotransmitters. This not only verifies the scientific basis of the ''fire-heat inducing stroke'' theory from a modern biological perspective but also provides conclusive evidence for the clinical application of heat-clearing and fire-purging therapy. LIU Wansu's ''fire-heat inducing stroke'' theory represents a major milestone in the historical understanding of stroke pathogenesis， and its academically transitional insights continue to hold core guiding value for the pattern identification and treatment of ischemic stroke today.

ObjectiveTo investigate whether Huanglian Jiedutang （HLJD） and its major active constituents （geniposide， baicalin， and berberine） can inhibit the inflammatory response of BV2 cells under lipopolysaccharide （LPS） stimulation via the high-mobility group protein B1 （HMGB1）/Toll-like receptor 4 （TLR4）/nuclear factor-κB （NF-κB） signaling pathway， and to explore differences in therapeutic efficacy among the three monomers， their combined formula， and HLJD under equal content ratios. MethodsBV2 microglial cells were used as the primary experimental model. Cell viability was assessed using the cell counting kit-8 （CCK-8） method to examine the effects of different concentrations of dimethyl sulfoxide （DMSO， 0.8%， 0.4%， 0.2%， 0.1%， and 0.05%） on cell viability. IncuCyte was employed to monitor the growth of cells under different concentrations of HLJD （200， 100， 50， 25， 12.5， 6.25 mg·L^-1）. Nitric oxide （NO） assay was used to screen the optimal HLJD concentration. High-performance liquid chromatography （HPLC） determined the content of geniposide， baicalin， and berberine in HLJD， and experimental groups were subsequently established according to the relative proportions of these constituents. CCK-8 assay evaluated cell viability under different treatments. Enzyme-linked immunosorbent assay （ELISA） measured levels of inflammatory factors （TNF-α， IL-1β， IL-6， IL-10） in the supernatant. Flow cytometry assessed the effects of treatments on M1-type polarization of BV2 cells. Western blot determined the expression levels of HMGB1， TLR4， and NF-κB-related proteins. ResultsCompared with the blank group， DMSO at concentrations ≤0.2% did not affect cell viability within 48 h. BV2 cell growth plateaued at 24 h after treatment with 200 mg·L^-1 HLJD. Under stimulation with 2 mg·L^-1 LPS， this concentration of HLJD effectively reduced NO release， and 6 h pre-treatment had a stronger inhibitory effect on NO than direct administration. HPLC results showed that 1 mg of HLJD freeze-dried powder contained approximately 24 μg of geniposide， 15 μg of baicalin， and 30 μg of berberine. Based on these ratios， experimental groups were blank， LPS （2 mg·L^-1）， HLJD （200 mg·L^-1）， monomer combination， geniposide （4.8 mg·L^-1）， baicalin （3 mg·L^-1）， and berberine （6 mg·L^-1）. The monomer combination group consisted of all three active constituents dissolved together. LPS and HLJD or its active constituents did not affect cell viability compared with the blank group. LPS significantly increased TNF-α， IL-1β， IL-6， and IL-10 in the supernatant （P<0.01）. HLJD and its active constituents significantly reduced pro-inflammatory factors TNF-α， IL-1β， and IL-6 （P<0.05， P<0.01） while upregulating anti-inflammatory IL-10 （P<0.01）， with the monomer combination showing the strongest effect （P<0.05， P<0.01）. Compared with the blank group， LPS significantly increased the proportion of CD80⁺CD86⁺ （M1-type） BV2 cells （P<0.01）. HLJD and its constituents partially inhibited M1 polarization （P<0.05， P<0.01）， with the monomer combination exhibiting the most pronounced effect （P<0.05， P<0.01）. Compared with the blank group， LPS upregulated HMGB1， TLR4， and NF-κB-related proteins （P<0.01）， whereas HLJD and its active constituents significantly reduced their expression （P<0.05， P<0.01）， with the monomer combination having the strongest regulatory effect （P<0.05， P<0.01）. ConclusionHLJD and its major active constituents （geniposide， baicalin， berberine） can inhibit LPS-induced inflammatory responses in BV2 cells. The combination of the three active constituents demonstrates the most potent anti-inflammatory effect， significantly attenuating M1-type polarization of BV2 cells via the HMGB1/TLR4/NF-κB signaling pathway.

ObjectiveTo reveal the molecular mechanism by which the traditional Chinese medicine compound prescription Qiangjing tablets regulate the aging of the testicular tissue and Leydig cells in rats through the cyclin-dependent kinase 4 （CDK4）-early 2 factor （E2F） signaling pathway. MethodsFor the cell experiment， 2-month-old SPF-grade SD male rats were selected and randomly assigned into a blank control group （administrated with an equal volume of 0.9% sodium chloride injection） and a Qiangjing tablets group （20 rats in each group） according to body weight. The Leydig cell model of aging was established by treatment of TM3 cells with 100 μmol·L^-1 H₂O₂， and the modeling performance was evaluated based on the levels of p16 and p21 determined by Western blot. The antioxidant NAC （1 mmol·L^-1） was used as the positive control for eliminating reactive oxygen species （ROS）. Cells were intervened with Qiangjing tablets-containing serum at low （2.5%）， medium （5%）， and high （10%） concentrations. The testosterone level in the cell supernatant was determined by enzyme-linked immunosorbent assay （ELISA）， and the protein levels of CDK4， E2F1， and E2F2 were analyzed by Western blot. In the animal experiment， 19-month-old naturally aging rats were used as the model group， and 2-month-old rats as the young control group. The positive control group was subcutaneously injected with 5.21 mg·kg^-1·d^-1 testosterone propionate. Qiangjing tablets were administered by gavage at low， medium， and high doses of 0.72， 1.44， 2.88 g·kg^-1·d^-1， respectively. The general conditions of rats were observed， and the protein levels of CDK4， E2F1， and E2F2 in the testicular tissue were determined by Western blot. ResultsIn the cell experiment， compared with the blank control group， the model group showed upregulated expression of CDK4 and E2F1 （P<0.05） and slightly downregulated expression of E2F2. Compared with that in the model group， the expression of CDK4 was upregulated in the NAC group and the low-dose Qiangjing tablets group （P<0.05）， slightly upregulated in the medium-dose Qiangjing tablets group， and downregulated in the high-dose Qiangjing tablets group （P<0.05）. The NAC group showed downregulated expression of E2F1 （P<0.05） and E2F2， and the low-， medium-， and high-dose Qiangjing tablets groups showed downregulated expression of both E2F1 and E2F2 （P<0.05）. Compared with that in the NAC group， the expression of CDK4 was upregulated in the low-dose Qiangjing tablets group and downregulated in the medium-dose and high dose （P<0.05） groups. The expression of E2F1 was down-regulated in all the three dose groups， with statistically significance in the high dose group （P<0.05）， and that of E2F2 were downregulated in all the three dose groups （P<0.05）. In the animal experiment， compared with the young control group， the model group exhibited downregulated expression of CDK4 （P<0.05） and slightly upregulated expression of E2F1 and E2F2. Compared with that in the model group， the expression of CDK4 decreased in the testosterone propionate group and the low-dose Qiangjing tablets group （P<0.05） but increased in the medium-dose （P<0.05） and high-dose groups. In addition， the expression of E2F1 decreased （P<0.05）， and that of E2F2 was slightly elevated. Compared with that in the NAC group， CDK4 expression was elevated in the Qiangjing tablets groups， with statistical significance in the medium- and high-dose groups （P<0.05）. Similarly， the E2F1 expression was also upregulated in the Qiangjing tablets groups， with statistical significance in the medium-dose group （P<0.05）. The expression of E2F2 was downregulated in all the Qiangjing tablets groups. ConclusionQiangjing tablets delay the aging process of Leydig cells and testicular tissue by up-regulating the expression of CDK4 and lowering the levels of E2F1 and E2F2.

OBJECTIVE To explore the improvement effect and potential mechanism of ginsenoside F1 （GF1） on allergic rhinitis （AR） rats based on the mitogen-activated protein kinase （MAPK）/signal transducer and activator of transcription 3 （STAT3） pathway. METHODS Male SD rats were divided into a control group （ n ＝15） and a modeling group （ n ＝55）. The AR rat model was established by basic sensitization with ovalbumin followed by local challenge. The successfully modeled rats were randomly assigned to the AR group， low-dose GF1 group [2.5 mg/（kg·d） ] ， high-dose GF1 group [5 mg/（kg·d） ] ， loratadine group （positive control， 1.5 mg/（kg·d） ] ， and high-dose GF1+MAPK activator group [5 mg/（kg·d） GF1+0.2 nmol C16-PAF ] ， with 10 rats in each group. Another 10 rats from the control group were randomly selected as the blank control group. Rats in each group received corresponding drug solutions or normal saline via intranasal instillation and/or oral gavage once daily for 28 consecutive days. After the final administration， AR symptoms were observed and rhinitis symptom scores were assessed. Histopathological changes of the nasal mucosa were examined. The number of inflammatory cells in nasal lavage fluid， serum levels of inflammatory cytokines [interleukin-4 （IL-4）， IL-17， interferon-γ （IFN-γ） ] and immunoglobulin E （IgE）， as well as the density of goblet cells， the number of mast cells， and the expression of MAPK/STAT3 pathway-related proteins in nasal mucosal tissues were measured. RESULTS Compared with the blank control group， the AR group exhibited marked pathological damage to the nasal mucosal epithelium， characterized by interstitial edema and inflammatory cell infiltration. The rhinitis symptom score， the number of macrophages， lymphocytes， eosinophils， neutrophils and mast cells， the density of goblet cells， the levels of IL-4， IL-17 and IgE， as well as the protein phosphorylation levels of p38 MAPK and STAT3 were significantly increased or elevated， while the level of IFN-γ was significantly decreased in the AR group （ P ＜0.05）. Compared with the AR group， all administration groups showed recovery of nasal mucosal epithelial pathological damage and significant improvements in all quantitative indicators， with the high-dose GF1 group and loratadine group showing more pronounced improvements than the low-dose GF1 group （ P ＜0.05）. C16-PAF significantly reversed the ameliorative effects of GF1 on all quantitative indicators （ P ＜0.05）. CONCLUSIONS GF1 can alleviate rhinitis symptoms in AR rats and inhibit inflammatory responses， which may be related to the inhibition of the MAPK/STAT3 pathway activation.

A recombinant adenovirus(rAd)for expression of Mycobacterium tuberculosis(M.tb)c-di-AMP phosphodiesterase CnpB was constructed,and its induced humoral immune response was detected.The codon-optimized gene of M.tb CnpB was cloned into the adenoviral plasmid pcADV.The recombinant plasmid pcADV-CnpB was transfected into HEK293T cells,and expression was detected with Western blot.The recombinant plasmid pcADV-CnpB and the backbone plasmid were co-transfected into HEK293T cells to obtain the recombinant adenovirus rAd-CnpB.rAd-CnpB was amplified in HEK293T cells,and the target protein expression of rAd-CnpB was detected with Western blot and immunofluorescence.Mice were immunized with rAd-CnpB intranasally,and their sera and bronchoalveolar lavage fluid(BALF)were collected.ELISA was used to detect levels of antigen-specific antibodies.Restriction enzyme digestion and sequencing indicated that the recombinant plasmid pcADV-CnpB was successfully constructed and led to protein expression in eukaryotic cells.rAd-CnpB was packaged and produced in HEK293T cells.After amplification and purification,rAd-CnpB with a titer of 5.53×1010 PFU/mL was obtained.rAd-CnpB led to CnpB expression in HEK293T cells.Intranasal immunization with rAd-CnpB increased levels of IgG and secretory IgA in BALF and led to high levels of IgG in sera.rAd-CnpB,the recombinant adenovirus for expression of c-di-AMP phosphodiesterase CnpB was successfully constructed,and was found to induce antigen-specific humoral and mucosal immune responses through mucosal immunization.Thus,rAd-CnpB may be used in further research on new TB vaccine strategies.

This study assessed the role and mechanism of the recombinant Bacillus Calmette-Gue?rin vaccine(rBCG)with c-di-AMP adjuvant in regulating metabolism and immunity in epididymal white adipose(eWAT)in mice.Male C57BL/6 mice were intravenously immunized with BCG and rBCG,and their body weights were monitored.eWAT was isolated from the mice,and the stromal vascular fractions(SVFs)cell number was counted with a hemocytometer.Sections of mouse adipose tissue were prepared,and the size,number,and morphology of eWAT adipocytes and crown-like structure(CLS)formation were compared under a microscope after HE staining.The transcription levels of lipid metabolism-associated factors,cytokines and aging-associated genes in each group were determined with qRT-PCR.The body weights of mice gradually increased after immunization with BCG and rBCG.The proportions of eWAT increased,and the SVFs cell number decreased,in rBCG immunized mice.HE staining indicated that BCG immunization promoted hyperplasia,whereas rBCG immunization promoted hypertrophy of eWAT adipocytes;moreover,both BCG and rBCG immunization induced CLS formation in eWAT.The qRT-PCR results indicated that rBCG immunization inhibited the expression of genes associated with lipolysis and energy expenditure in eWAT.BCG immunization had little effect on cytokine transcription,whereas rBCG significantly induced the transcription of IFN-γ and IL-1Ra,and inhibited that of IL-15 and IL-2,but did not induce the expression of aging-associated genes.Thus,rBCG immunization induced eWAT adipocyte hypertrophy,which was associated with the inhibition of eWAT lipolysis and the regulation of cytokine expression.

The objective of this study was to evaluate the toxicity and safety of novel Mycobacterium tuberculosis fusion strain protein derivatives,referred to as B/R strain active proteins.In cellular experiments,RAW264.7 cells were treated with each vaccine preparation,and apoptosis rates were measured.In subsequent animal experiments,C57BL/6 mice were immunized via subcutaneous injection,and their survival and body weight changes were monitored and recorded at 2,4,8,12,and 16 weeks.The lungs and spleens were harvested to calculate organ coefficients,and pathological examinations were conducted.At the eighth week of immunization,the mice were infected with high concentrations of BCG,and pathological changes in the lungs and spleens were observed 4 weeks post-infection.The apoptosis rate at 6 hours was significantly higher in the experimental group than the PBS group(P<0.05).At 12 and 24 hours,the apoptosis rate in the experimental group remained higher than that in the PBS group,although this difference was not statistically significant.After immunization,mice in all four groups exhibited normal growth patterns,as indicated by stable body weight changes.At 4 and 12 weeks post-immunization,the lung coefficients in the protein group were significantly higher than those in the PBS group at the same time points.Additionally,the lung coefficients in the BCG group were significantly elevated across all time periods(P<0.05).The spleen coefficients in the protein and BCG groups were significantly higher than those in the PBS group at 2,4,8,12,and 16 weeks,whereas the ICD B/R group showed higher spleen coefficients than the PBS group only at week 8(P<0.05).Pathological examination revealed normal lung and spleen tissues in the PBS group.However,during the 2-8 weeks immunization period,lung and spleen tissues in all experimental groups exhibited varying degrees of damage,which gradually diminished by 12-16 weeks.Notably,no tuberculosis nodules were observed in any experimental group.After infection with high concentrations of BCG,no overt pathological changes were observed on the surfaces of the lungs and spleens in any group.Microscopic examination revealed less severe pathological changes in the lungs and spleens of mice in the experimental groups than the PBS group.Furthermore,no statistically significant differences were observed between the protein group and the BCG group.Our findings suggested that the B/R strain active proteins'toxicity and safety profiles were comparable to those of BCG,and showed immunoprotective effects.This study provides an experimental foundation for the development of a novel tuberculosis vaccine.

Objective:To investigate the impact of postoperative complications on adverse outcomes following curative-intent resection for gallbladder cancer (GBC).Methods:The multi-center real-world study was conducted. The clinicopathological data of 629 patients with GBC, who were admitted to 14 medical centers including The First Affiliated Hospital of Army Medical University from the national multicenter database of Biliary Surgery Group of Elite Group of Chinese Journal of Digestive Surgery, from April 2020 to April 2024 were collected. There were 225 males and 404 females, aged (64±10)years. Patients underwent open curative-intent resection for GBC. Observation indicators: (1)surgery, postoperative complica-tions and adverse outcomes; (2) analysis of risk factors affecting postoperative adverse outcomes in patients and population attributable fraction (PAF). Missing data in predictor variables were addressed using multiple imputation with chained equations, while cases with missing outcome variables were addressed using the "multiple imputation then deletion (MID)" strategy. The severity of multicollinearity among independent variables was assessed using the variance inflation factor (VIF) test. Multivariable possion regression models with log link and robust error variance were construc-ted incorporating restricted cubic splines (3 knots) to address nonlinear relationships in continuous variables, calculating adjusted relative risk ( RR) with corresponding 95% confidence interval ( CI). Adjusted PAF was calculated for each imputed dataset using the AF package of R software, with subsequent pooling performed according to Rubin's rules. Results:(1) Surgery, postoperative complications and adverse outcomes. All 629 patients underwent curative-intent resection for GBC, of which 143 cases had postoperative complications, including 68 cases of intra-abdominal ascites, 39 cases of pulmonary infection, 21 cases of bile leakage, 12 cases of intra-abdominal hemorrhage, 11 cases of liver failure, 10 cases of pan-creatic fistula, 10 cases of wound infection, 10 cases of gastroparesis, 7 cases of cholangitis, 7 cases of sepsis. The same patient could have more than one kind of complication. Of 629 patients, there were 19 cases of postoperative 90-day death and 11 cases of missing data, 42 cases with post-operative 90-day reoperation and 7 cases with missing data, 44 cases with postoperative 90-day readmission and 3 cases with missing data, 155 cases with prolonged postoperative hospital stay and 3 cases with missing data. (2) Analysis of risk factors affecting the postoperative adverse outcomes in patients and PAF. Results of multivariate analysis showed that pulmonary infection and liver failure were independent risk factors for postoperative 90-day mortality ( RR=3.74, 12.15, 95% CI as 1.18-11.83, 1.98-74.48, P<0.05). Pulmonary infection demons-trated the highest PAF as 4.61% (95% CI as 3.94%-5.28%, P<0.05). Intra-abdominal ascites, pulmonary infection, bile leakage, and intra-abdominal hemorrhage were independent risk factors for post-operative 90-day reoperation ( RR=4.80, 3.62, 3.46, 4.99, 95% CI as 2.49-9.26, 1.42-9.21, 1.34-8.92, 1.55-16.06, P<0.05). Intra-abdominal ascites demonstrated the highest PAF as 8.65% (95% CI as 8.22%-9.08%, P<0.05). Intra-abdominal ascites, bile leakage, and liver failure were independent risk factors for postoperative 90-day readmission ( RR=6.20, 3.33, 14.33, 95% CI as 3.21-11.95, 1.33-8.35, 3.72-55.28, P<0.05). Intra-abdominal ascites demonstrated the highest PAF as 9.11% (95% CI as 8.85%-9.37%, P<0.05). Intra-abdominal ascites, pulmonary infection, bile leakage, liver failure, and wound infection were independent risk factors for prolonged postoperative hospital stay ( RR=2.29, 2.21, 2.26, 2.14, 3.35, 95% CI as 1.63-3.23, 1.41-3.46, 1.32-3.86, 1.11-4.13, 1.70-6.60, P<0.05). Intra-abdominal ascites demonstrated the highest PAF as 6.03% (95% CI as 5.71%-6.35%, P<0.05). Conclusion:Pulmonary infection is the most significant risk factor for postoperative 90-day mortality after curative-intent resection for GBC, while intra-abdominal ascites is the most significant risk factor for postoperative 90-day reoperation, postoperative 90-day readmission, and prolonged postoperative hospital stay.

BACKGROUND:Previously,a SENP1 gene-silenced human alveolar epithelial cell line was successfully constructed in vitro,and the role of SENP1 in hyperoxic lung injury was investigated at the cellular level.OBJECTIVE:To construct a mouse model of alveolar type II epithelial cell-specific knockout of SENP1 gene based on the Cre-loxP recombinase system.METHODS:SENP1flox/-mice were self-crossed to obtain SENP1flox/flox and SENP1flox/-mice;Sftpc-Cre+/+mice were crossed with wild-type mice to obtain more Sftpc-Cre+/-mice.Sftpc-Cre+/+or offspring Sftpc-Cre+/-mice were crossed with SENP1flox/-or offspring SENP1flox/flox mice to obtain SENP1flox/-Sftpc-Cre+/-double heterozygous mice.SENP1flox/-Sftpc-Cre+/-mice were then crossed with SENP1flox/flox mice to obtain SENP1flox/floxSftpc-Cre+/-mice.The genomic DNA was extracted by tail clipping and amplified by PCR.The amplified product was subjected to agarose gel electrophoresis to determine the mouse genotypes.Lung tissues of SENP1flox/flox and SENP1flox/floxSftpc-Cre+/-mice were subjected to immunofluorescence double-labelling and western blot assay to verify the knockdown effect of SENP1 gene.Heart,liver,lung and kidney tissues of SENP1flox/flox and SENP1flox/floxSftpc-Cre+/-mice were stained with hematoxylin-eosin to observe the histomorphology of each organ in the two groups of mice.RESULTS AND CONCLUSION:SENP1flox/floxSftpc-Cre+/-mice were correctly screened by agarose gel electrophoresis.Immunofluorescence double-labeling experiments showed that the mean fluorescence intensity of SENP1 was reduced in lung tissues of SENP1flox/floxSftpc-Cre+/-mice compared with that of SENP1flox/flox mice(P<0.01)and no significant co-localization of SENP1 and Sftpc was observed(P<0.01).Western blot results showed that SENP1 protein expression was reduced in lung tissues of SENP1flox/floxSftpc-Cre+/-mice compared with SENP1flox/flox mice(P<0.001).Hematoxylin-eosin staining showed no significant alterations in the histomorphology of heart,liver,lung and kidney tissues in SENP1flox/flox and SENP1flox/floxSftpc-Cre+/-mice.This study successfully constructed alveolar type II epithelial cell-specific knockout SENP1 gene mice using the Cre-loxP recombinase system,which provides a good tool for the subsequent study of the role of SENP1 gene in lung diseases such as bronchopulmonary dysplasia and idiopathic pulmonary fibrosis,in which alveolar type II epithelial cells are the main damage cells.