Animal experiments are widely used in biomedical research for safety assessment, toxicological analysis, efficacy evaluation, and mechanism exploration. In recent years, the ethical review system has become more stringent, and awareness of animal welfare has continuously increased. To promote more efficient and cost-effective drug research and development, the United States passed the Food and Drug Administration (FDA) Modernization Act 2.0 in September 2022, which removed the federal mandate requiring animal testing in preclinical drug research. In April 2025, the FDA further proposed to adopt a series of "new alternative methods" in the research and development of drugs such as monoclonal antibodies, which included artificial intelligence computing models, organoid toxicity tests, and 3D micro-physiological systems, thereby gradually phasing out traditional animal experiment models. Among these cutting-edge technologies, 3D bioprinting models are a significant alternative and complement to animal models, owing to their high biomimetic properties, reproducibility, and scalability. This review provides a comprehensive overview of advancements and applications of 3D bioprinting technology in the fields of biomedical and pharmaceutical research. It starts by detailing the essential elements of 3D bioprinting, including the selection and functional design of biomaterials, along with an explanation of the principles and characteristics of various printing strategies, highlighting the advantages in constructing complex multicellular spatial structures, regulating microenvironments, and guiding cell fate. It then discusses the typical applications of 3D bioprinting in drug research and development,including high-throughput screening of drug efficacy by constructing disease models such as tumors, infectious diseases, and rare diseases, as well as conducting drug toxicology research by building organ-specific models such as those of liver and heart. Additionally,the review examines the role of 3D bioprinting in tissue engineering, discussing its contributions to the construction of functional tissues such as bone, cartilage, skin, and blood vessels, as well as the latest progress in regeneration and replacement. Furthermore, this review analyzes the complementary advantages of 3D bioprinting models and animal models in the research of disease progression, drug mechanisms, precision medicine, drug development, and tissue regeneration, and discusses the potential and challenges of their integration in improving model accuracy and physiological relevance. In conclusion, as a cutting-edge in vitro modeling and manufacturing technology, 3D bioprinting is gradually establishing a comprehensive application system covering disease modeling, drug screening, toxicity prediction, and tissue regeneration.

Animal experiments are widely used in biomedical research for safety assessment, toxicological analysis, efficacy evaluation, and mechanism exploration. In recent years, the ethical review system has become more stringent, and awareness of animal welfare has continuously increased. To promote more efficient and cost-effective drug research and development, the United States passed the Food and Drug Administration (FDA) Modernization Act 2.0 in September 2022, which removed the federal mandate requiring animal testing in preclinical drug research. In April 2025, the FDA further proposed to adopt a series of "new alternative methods" in the research and development of drugs such as monoclonal antibodies, which included artificial intelligence computing models, organoid toxicity tests, and 3D micro-physiological systems, thereby gradually phasing out traditional animal experiment models. Among these cutting-edge technologies, 3D bioprinting models are a significant alternative and complement to animal models, owing to their high biomimetic properties, reproducibility, and scalability. This review provides a comprehensive overview of advancements and applications of 3D bioprinting technology in the fields of biomedical and pharmaceutical research. It starts by detailing the essential elements of 3D bioprinting, including the selection and functional design of biomaterials, along with an explanation of the principles and characteristics of various printing strategies, highlighting the advantages in constructing complex multicellular spatial structures, regulating microenvironments, and guiding cell fate. It then discusses the typical applications of 3D bioprinting in drug research and development,including high-throughput screening of drug efficacy by constructing disease models such as tumors, infectious diseases, and rare diseases, as well as conducting drug toxicology research by building organ-specific models such as those of liver and heart. Additionally,the review examines the role of 3D bioprinting in tissue engineering, discussing its contributions to the construction of functional tissues such as bone, cartilage, skin, and blood vessels, as well as the latest progress in regeneration and replacement. Furthermore, this review analyzes the complementary advantages of 3D bioprinting models and animal models in the research of disease progression, drug mechanisms, precision medicine, drug development, and tissue regeneration, and discusses the potential and challenges of their integration in improving model accuracy and physiological relevance. In conclusion, as a cutting-edge in vitro modeling and manufacturing technology, 3D bioprinting is gradually establishing a comprehensive application system covering disease modeling, drug screening, toxicity prediction, and tissue regeneration.

Objective: To design and establish a new method for flow cytometry-based detection of commonly observed highly expressed antigens on red blood cells, and to further evaluate the differences and distribution characteristics of antigen expression levels between ABO blood type homozygotes and heterozygotes in healthy individuals. Methods: Residual blood samples after donor blood type identification by Shanghai Blood Center in April 2024 were collected. Among them, samples of 19 homozygous and 19 heterozygous individuals of type A and type B were selected. Then the expression level of ABO antigen on red blood cells were detected using the new method established in this study and the traditional aldehyde fixed red blood cell method. Both methods were tested independently three times and the results were compared. Results: The mean values of the three detection results of the new method was (×10 /RBC): AA homozygous 3.3±0.5, AO heterozygous 2.8±0.3, BB homozygous 3.6±0.3, BO heterozygous 3.1±2.8. The mean values of the three detection results of the aldehyde fixation method were AA homozygous 5.9±0.9, AO heterozygous 5.0±1.4, BB homozygous 3.8±0.6, and BO heterozygous 3.3±0.4. The average antigen distribution of each genotype followed a normal distribution. Comparing the average antigen expression levels of homozygotes and heterozygotes, both methods showed that A/B homozygotes had higher antigen levels than heterozygotes, with AA being 1.17 to 1.18 times that of AO and BB being 1.15 to 1.16 times that of BO. Comparing the inter batch differences in the three test results of two methods, the new method showed no significant difference in the three test results for four genotypes (P>0.05). The aldehyde fixation method showed significant differences in the test results for all three genotypes (P<0.01) except for BB homozygotes (P>0.05). The reliability and reproducibility of the new method were better than those of the traditional aldehyde fixation method. Conclusion: The antigen expression level of ABO homozygotes is higher than that of heterozygotes, and the difference in antigen level between type A homozygotes and heterozygotes is slightly higher than that of type B. The new method is superior to traditional aldolization fixation methods.

Objective To investigate the clinical value of coronary computed tomography angiography(CCTA)based CT derived fractional flow reserve(CT-FFR)and ΔCT-FFR in improving the diagnostic efficiency for coronary abnormal hemodynamics in patients with severe calcification.Methods We retrospectively analyzed the clinical data of coronary artery disease(CAD)patients who underwent CCTA,CT-FFR,invasive coronary angiography(ICA)and FFR during hospitalization from January 2018 to June 2019 in Chinese PLA General Hospital.Severe calcification was defined as coronary artery calcium score(CACS)≥100 on single vessel level.A total of 107 CAD patients with 149 coronary arteries were included in the present study.The enrolled coronary arteries were assigned to CACS≥100 group(n=56)and CACS<100 group(n=93).CT-FFR was performed on the deep FFR platform based on machine learning(ML)algorithms and ΔCT-FFR was defined as CT-FFR difference between proximal and distal to the coronary lesion.The correlation and consistency between CT-FFR and FFR values were analyzed by Pearson and Bland-Altman methods.We attempted to analyze the incremental value of ΔCT-FFR for coronary functional evaluation,especial for coronary arteries with severe calcification,regarding FFR≤0.8 as the diagnostic gold standard.Comparison of receiver operating characteristic curves(ROC)between different diagnostic methods was presented by Delong test.Results Pearson and Bland-Altman analyses showed appreciable correlation(CACS≥100 group,r=0.71,P<0.01;CACS<100 group,r=0.73,P<0.01)and consistency(CACS≥100 group,Mean=-0.01,P=0.25;CACS<100 group,Mean=0,P=0.96)between CT-FFR and FFR values in both groups.FFR(0.80±0.08 vs.0.84±0.09,P=0.004)and CT-FFR(0.81±0.06 vs.0.85±0.06,P<0.001)levels were significant lower in CACS≥100 group than those in CACS<100 group,while ΔCT-FFR(0.14±0.06 vs.0.09±0.06,P<0.001)levels were significant higher in CACS≥100 group.Moreover,the diagnostic efficiency of CT-FFR in CACS≥100 group was inferior to that in CACS<100 group[AUC=0.792(95%CI 0.663-0.889)vs.AUC=0.929(95%CI 0.856-0.972),P=0.04],while it achieved significant improvement after ΔCT-FFR adjustment[AUC=0.876(95%CI 0.760-0.949)vs.AUC=0.792(95%CI 0.663-0.889),P=0.02]and was similar to that in CACS<100 group(P=0.37).Conclusion For coronary arteries with severe calcification,CT-FFR demonstrated significant incremental value in improving the diagnostic efficiency of coronary abnormal hemodynamics after ΔCT-FFR adjustment.

Objective:To explore the prognostic value of MUC13 expression in gastric cancer(GC)patients and its impact on the biological behavior of GC cells.Methods:Comprehensive anal-ysis of the expression pattern of MUC genes in GC tissues based on the TCGA database to screen for differentially expressed genes.Spearman correlation analysis determined the correlation of ex-pression between MUC genes in GC tissues.Gene Ontology(GO)functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway(KEGG)enrichment analysis were used to explore the potential biological functions of MUC genes.Univariate COX regression analysis was performed to explore the relationship between all differentially expressed MUC genes and the prog-nosis of GC patients to screen out MUC genes that were significantly related to the prognosis of GC.Clinical GC tissue samples were used to further verify the expression of MUC13 through im-munofluorescence,and its relationship with the clinicopathological characteristics and prognosis of GC was analyzed.siRNA was used to silence the expression of MUC13 in GC cells,and the effect of MUC13 on cell proliferation,migration and invasion was analyzed through CCK-8,colony forma-tion and Transwell experiments.Results:Among all MUC members,the expression levels of MUC1,MUC2,MUC3A,MUC4,MCU5B,MUC12,and MUC13 were significantly upregulated in GC tissues(P＜0.05).There are certain interactions between these MUC genes,and they are mainly en-riched in pathways related to digestive system processes,epithelial structure maintenance,apical plasma membrane,saliva secretion,etc.Importantly,upregulation of MUC13 in GC tissues indicates poor patient prognosis(Log-rank P＜0.05).In addition,MUC13 expression was significantly correlat-ed with the age(P＜0.001)of GC patients and tumor size(P=0.035).Further cell function experiments showed that after silencing MUC13,the proliferation ability of GC cells was significantly reduced(P＜0.05),while their migration and invasion abilities were not significantly affected(P＞0.05).Con-clusions:Highly expressed MUC13 is closely related to the poor prognosis of gastric cancer,par-ticipates in the regulation of tumor progression and is a potential therapeutic target and prognostic marker for gastric cancer.

Objective:To investigate the risk factors and their warning effectiveness for postoperative intestinal barrier dysfunction (IBD) in patients with severe traumatic brain injury (sTBI).Methods:A retrospective cohort study was conducted to analyze the clinical data of 101 patients with sTBI admitted to Wuxi Branch of Zhongda Hospital Affiliated to Southeast University from May 2020 to February 2023, including 63 males and 38 females, aged 21-81 years [(53.4±14.2)years]. All the patients underwent emergency surgery. The patients were divided into IBD group ( n=67) and non-IBD group ( n=34) according to whether or not they had IBD after surgery. The gender, age, basic diseases (hypertension and diabetes), types of intracranial hematoma (subdural, epidural, and intracerebral hematoma), preoperative Glasgow Coma Scale (GCS), cerebral hernia, intraoperative initial intracranial pressure (iICP), operation time, removal of bone flap, treatment time in ICU, initiation time of enteral nutrition, and use of broad-spectrum antibiotics were recorded in the two groups. Univariate and multivariate binary Logistic regression analyses were conducted to assess the correlations between above-mentioned indicators and incidence of postoperative IBD in sTBI patients and determine the independent risk factors for sTBI. Receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to evaluate the warning effectiveness of each risk factor for IBD. Results:The results of the univariate analysis showed that preoperative GCS, cerebral hernia, intraoperative iICP, removal of bone flap, treatment time in ICU, initiation time of enteral nutrition, and use of broad-spectrum antibiotics were significantly correlated with the incidence of IBD in sTBI patients ( P<0.05 or 0.01), while there were no correlations of IBD with gender, age, basic diseases, types of intracranial hematoma and operation time ( P>0.05). The results of the multivariate binary Logistic regression analysis showed that preoperative GCS≤5 points ( OR=2.49, 95% CI 1.17, 5.32, P<0.05), intraoperative iICP>23 mmHg (1 mmHg=0.133 kPa)( OR=1.20, 95% CI 1.03, 1.39, P<0.05), and initiation time of enteral nutrition>24 hours ( OR=10.03, 95% CI 1.26, 80.21, P<0.05) were highly correlated with postoperative IBD in sTBI patients. The results of the ROC curve analysis showed that intraoperative iICP had the highest warning value (AUC=0.91, 95% CI 0.85, 0.96), followed by preoperative GCS (AUC=0.88, 95% CI 0.82, 0.95), and initiation time of enteral nutrition had the lowest warning value (AUC=0.78, 95% CI 0.69, 0.87). Conclusions:Preoperative GCS≤5 points, intraoperative iICP>23 mmHg, and initiation time of enteral nutrition>24 hours are independent risk factors for postoperative IBD in sTBI patients. The warning value of intraoperative iICP ranks the highest for postoperative IBD in sTBI patients, followed by preoperative GCS, with initiation time of enteral nutrition having the lowest warning value.

BACKGROUND:Currently,a variety of mesenchymal stem cells have been confirmed to have the effect of promoting wound repair,but there is still a lack of relevant research on whether placenta-derived mesenchymal stem cells can promote acute skin wound healing. OBJECTIVE:To investigate the effect of placenta-derived mesenchymal stem cell transplantation on the healing of acute skin wound in rats. METHODS:Twenty SD rats were divided into PBS group and stem cell group by the random number table method,with 10 rats in each group.All rats were selected to establish a full-thickness skin defect model.In the PBS group and stem cell group,PBS buffer and placenta-derived mesenchymal stem cells were immediately injected on the wound surface and wound margin immediately and on day 8 after modeling.The wound healing was observed immediately and on days 2,4,6,8,10,12,and 14 after modeling.The skin tissue of the wound surface was taken on day 14 and treated with hematoxylin-eosin staining,Masson staining,immunohistochemical staining and immunofluorescence staining. RESULTS AND CONCLUSION:(1)The wound surface of the rats in each group decreased with the prolongation of treatment time.The wound healing rate and wound epithelization rate of the stem cell group at 14 days were higher than those of the PBS group(P<0.01),and the wound contracture rate was lower than that of the PBS group(P<0.01).(2)The results of hematoxylin-eosin staining showed that the skin wound healing of the stem cell group was better than that of the PBS group;the degree of wound epithelization was higher,and the morphology of collagen fibers was close to that of normal skin.(3)Masson staining results showed that compared with the PBS group,collagen fibers in the skin wound tissue of the stem cell group were significantly increased and thicker,and the content of collagen fibers in the new tissue was significantly higher than that of the PBS group(P<0.01).(4)Immunohistochemical staining showed that the number of new capillaries in the stem cell group was higher than that in the PBS group(P<0.01),while the expressions of tumor necrosis factor-α and interleukin-6 were lower than those in the PBS group(P<0.01).(5)Immunofluorescence staining showed that the number of M2 macrophages in the new wounds of the stem cell group was higher than that of the PBS group(P<0.01),while the number of M1 macrophages was less than that in the PBS group(P<0.01).These findings indicate that placenta-derived mesenchymal stem cells can accelerate skin wound healing,promote wound epithelization,and reduce wound contracture,which may be related to the promotion of capillary angiogenesis,regulation of collagen fiber production,inhibition of inflammation,and regulation of macrophage polarization to M2 type.

Objective:To develop a grading system for necrosis of pedicled flaps in reconstruction of foot and ankle, and to verify its effectiveness and repeatability.Methods:A retrospective observational study was conducted. A total of 40 necroses of foot and ankle pedicled flaps were selected by 2 senior surgeons based on the flap surgery performed by the same surgical group in Department of Orthopaedic Surgery, the 920 Hospital of Joint Logistic Support Force of PLA from January 2010 to January 2022. A grading system for pedicled flap necrosis was proposed by a working group and the 40 necrotic flaps were graded. The coincidence rate was calculated to evaluate the effectiveness of the grading system through correlation studies between grading and clinical treatment. One photo of a typical postoperative necrotic flap was collected from each of the 40 flaps. Then 5 extramural surgeons were asked to grade the necroses shown on the photos according to the proposed grading system. Moreover, weighted Kappa analysis was performed on the results of proposed grading system and also on the standard grading currently in use, to evaluate the repeatability of the proposed grading system. Evaluated data were expressed by Mean±SD, and the coincidence rate was expressed by percentage. The reproducibility was studied by weighted Kappa analysis.Results:Of the 40 necrotic flaps, 7 flaps were classified in Grade I, 16 in Grade Ⅱ, 12 in Grade Ⅲ and 5 in Grade IV. In comparison with the actual treatment methods, the overall coincidence rate of the grading system was 92.5%. It indicated that the proposed grading system could effectively guide the selection of a treatment procedure. The average weighted Kappa coefficient of surgeons was at 0.628 with a 95% confidence interval (95%CI) between 0.460-0.796, which was strongly consistent with the standard of the grading system currently in use.Conclusion:The grading system for necrosis of pedicled flap in reconstruction of foot and ankle proposed in this study is simple and clear. It is able to effectively guide the treatment of flap necrosis. The preliminary validation shows that the classification system has good repeatability.

Objective:To investigate the impact of proximal versus total gastrectomy on survival outcomes in patients with advanced upper gastric cancer following neoadjuvant therapy, aiming to provide evidence-based guidance for optimal surgical approach selection.Methods:A retrospective cohort study was conducted to collect clinical data from 114 patients with upper gastric cancer who underwent surgical treatment after neoadjuvant therapy in the PLA General Hospital between November 2014 and November 2023, consisting of 96 males and 18 females, with an age range of 41 to 78 years and a median age of 64 years. According to the extent of surgical resection, 44 patients underwent proximal gastrectomy (PG), and 70 patients underwent total gastrectomy (TG). Propensity score matching was used to match patients with advanced upper gastric cancer who received proximal gastrectomy or total gastrectomy after neoadjuvant therapy based on factors such as gender, age, surgical approach, BMI, ypT stage, ypN stage, tumor size, R0 resection status, neoadjuvant therapy cycles, and neoadjuvant therapy regimen, with a 1∶1 matching ratio. In the end, 44 patients in the PG group and 44 patients in the TG group were successfully matched and analyzed. The primary outcomes were overall survival (OS) and disease-free survival (DFS), while secondary outcomes included operative duration, R0 resection rate, complication rate, total number of lymph nodes dissected, number of lymph nodes dissected in each group, and lymph node metastasis rate. Data analysis was performed using SPSS 25.0, and survival curves were generated using the Kaplan-Meier (K-M) method.Results:After propensity score matching, the operative time in the TG group was significantly longer than that in the PG group [(222.0±42.5) min vs (257.0±62.0) min, χ2=3.07, P=0.003], while the differences in other baseline characteristics between the two groups were not statistically significant ( P>0.05). In terms of postoperative complications, the incidence of Clavien-Dindo grade II or higher complications was 29.5% in the PG group and 34.1% in the TG group ( P=0.819), indicating no significant difference. The 5-year overall survival (OS) rates were 55.8% for the PG group and 49.5% for the TG group ( P=0.592), showing no statistically significant difference. Lymph node metastasis rates in the TG group were 5.71% (4/70) in group 4d, 4.29% (3/70) in group 5, 2.86% (2/70) in group 6, and 2.86% (2/70) in group 12a. Conclusions:For patients with advanced upper gastric cancer who undergo proximal gastrectomy or total gastrectomy following neoadjuvant therapy, there is no significant difference in perioperative complications and long-term survival rates. Therefore, proximal gastrectomy is a safe and reliable option for these patients, allowing partial preservation of gastric function and potentially improving quality of life.

Diabetic wound is a complication of diabetes, which is difficult to heal and easy to turn into chronic wound. Compared with ordinary wound healing, diabetic wounds stay in the inflammatory stage and can not enter the proliferative stage. This is because the proportion of pro-inflammatory cytokines increases, leading to the imbalance of inflammatory cells and the accumulation of a large number of inflammatory factors. The production and release of inflammatory factors is closely related to pyroptosis. Pyroptosis is a kind of programmed death mode of inflammatory cells. Mediated by inflammasome, pyroptosis is transduced through typical and atypical inflammasome signaling pathways, resulting in the formation of pores on the cell membrane and inducing cell death. In this process, a large number of pro-inflammatory cytokines are released to maintain the inflammatory environment of wounds, hindering the development of diabetic wounds to the proliferative stage and remodeling stage, thus inhibiting the healing of diabetic wounds. This article reviews the mechanism of pyroptosis and its effect on diabetic wounds, the potential significance of inhibiting pyroptosis in the treatment of diabetic wounds, and the existing problems.