OBJECTIVE: To prepare decellularized nerve grafts from alpha-1, 3-galactosyltransferase (GGTA1) gene-edited pigs and explore their biocompatibility for xenotransplantation. METHODS: The sciatic nerves from wild-type pigs and GGTA1 gene-edited pigs were obtained and underwent decellularization. The alpha-galactosidase (α-gal) content in the sciatic nerves of GGTA1 gene-edited pigs was detected by using IB4 fluorescence staining and ELISA method to verify the knockout status of the GGTA1 gene, and using human sciatic nerve as a control. HE staining and scanning electron microscopy observation were used to observe the structure of the nerve samples. Immunofluorescence staining and DNA content determination were used to evaluate the degree of decellularization of the nerve samples. Fourteen nude mice were taken, and subcutaneous capsules were prepared on both sides of the spine. Decellularized nerve samples of wild-type pigs ( n=7) and GGTA1 gene-edited pigs ( n=7) were randomly implanted in the subcutaneous capsules. Blood was drawn at 1, 3, 5, and 7 days after implantation to detect neutrophil counting. RESULTS: IB4 fluorescence staining and ELISA detection showed that GGTA1 gene was successfully knocked out in the nerves of GGTA1 gene-edited pigs. HE staining showed that the structure of the decellularized nerve from GGTA1 gene-edited pigs was well preserved; the nerve basement membrane tube structure was visible under scanning electron microscopy; no cell nuclei was observed, and the extracellular matrix components was retained in the nerve grafts by immunofluorescence staining; and the DNA content was significantly reduced when compared with the normal nerves ( P<0.05). In vivo experiments showed that the number of neutrophils in the two groups were similar at 1, 3, and 7 days after implantation, with no significant difference ( P>0.05); only at 5 days, the number of neutrophils was significantly lower in the GGTA1 gene-edited pigs than in the wild-type pigs ( P<0.05). CONCLUSION The decellularized nerve grafts from GGTA1 gene-edited pigs have well-preserved nerve structure, complete decellularization, retain the natural nerve basement membrane tube structure and components, and low immune response after xenotransplantation through in vitro experiments.
Animals ; Transplantation, Heterologous ; Galactosyltransferases/genetics* ; Sciatic Nerve/immunology* ; Swine ; Tissue Engineering/methods* ; Humans ; Graft Rejection/prevention & control* ; Gene Editing ; Mice ; Mice, Nude ; Heterografts/immunology* ; Animals, Genetically Modified ; Tissue Scaffolds ; Decellularized Extracellular Matrix

Objective:To propose a deep learning（DL）-based ultrasound imaging auxiliary tool for automatic segmentation and recognition of the brachial plexus（BP），and to enhance the accuracy and safety of clinical procedures.Methods:It was a multicenter study that collected 773 healthy subjects from Peking University Third Hospital and its branch campuses，the Third Medical Center of the Chinese PLA General Hospital，and Shanghai Eighth People's Hospital between August 2024 and February 2025. Brachial plexus（BP）images in the interscalene groove were captured used high-frequency ultrasound by senior sonographers，a dataset comprising 1 289 standardized images were constructed and the improved model（CHA-TransUNet）was trained. The test set was input into 6 different models（CHA-TransUNet，R50-Unet，TransUnet，SegFormer，SwinUnet，MISSFormer）for segmentation. Segmentation accuracy was evaluated using metrics including the Dice similarity coefficient（DSC），95% Hausdorff distance（HD95）and mean intersection over union（mIoU），and was compared with the segmentation results of 3 ultrasound physicians with varying experience levels（junior physicians and senior physicians）to validate the model's segmentation efficacy.Results:The CHA-TransUNet model established based on a dataset of 1 289 standardized images achieved segmentation results for the BP with a DSC of 90.15%，mIoU of 91.02%，and HD95 of 8.08. Its accuracy was higher than other mainstream models（DSC：90.15% vs. 87.60%，87.77%，81.35%，84.78%，84.55%），significantly better than junior physicians（DSC：90.15% vs. 68.73%， Z=-127.76， P<0.001），and approached the level of senior physician（DSC：90.15% vs. 86.15%， Z=-31.33， P=0.549）. The model demonstrated superior boundary recognition in complex anatomical structures（e.g.，C6/C7 nerve roots）compared to ultrasound physicians（junior and senior）（HD95：8.08 vs. 26.34，17.44，56.80）. Conclusions:This study proposes an analysis model for BP ultrasound images，CHA-TransUNet. This model achieves segmentation and recognition of the BP with relatively complex pathways and structures. The model exhibits high accuracy and stability，outperforming current mainstream network models and junior physicians while approaching the performance level of senior physicians. It assists junior physicians or trainees in more accurately identifying and localizing the BP.

Objective:To evaluate the effect of dexmedetomidine on Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor κB (NF-κB) signaling pathway in the hippocampus of mice with cognitive impairment after traumatic brain injury (TBI).Methods:Sixty specific pathogen-free healthy adult wild-type C57BL/6 mice, aged 21-23 months, weighing 28-34 g, were divided into 5 groups ( n=12 each) by a random number table method: sham operation + vehicle group (SV group), sham operation + dexmedetomidine group (SD group), TBI + vehicle group (TV group), TBI + dexmedetomidine group (TD group) and TBI + TLR4 inhibitor TAK-242 group (TT group). The modified Feeney free fall epidural impact method was used to establish a mild TBI model. At 30 min before model preparation, dexmedetomidine 25 μg/kg was intraperitoneally injected in SD group and TD group, TAK-242 10 mg/kg was intraperitoneally injected in TT group, and the equal volume of normal saline was intraperitoneally injected in SV group and TV group. Neurological severity scores (NSSs) were used to evaluate the neurological function at 1, 7 and 14 days after developing the model. The novel object recognition test (recognition index) and fear conditioning test (the percentage of freezing time related to context and sound) were used to evaluate the cognitive function of mice at 16 days after developing the model. The number and morphology of hippocampal neurons (NeuN-positive cells) and activated microglia (ionized calcium-binding adaptor molecule 1[IBA1]-positive cells) were measured by immunofluorescent staining. The expression of interleukin-1beta (IL-1β), IL-6, tumor necrosis factor-alpha (TNF-α), TLR4, MyD88 and nuclear factor kappa B (NF-κB) was detected by Western blot. Results:Compared with SV group, the NSS was significantly increased, the recognition index was decreased, the percentage of freezing time related to context and sound was decreased, the number of NeuN-positive cells was decreased, the number of IBA1-positive cells was increased and the cell body area was enlarged, the total branch length and intersection points were decreased, and the expression of TLR4, MyD88, NF-κB, IL-1β, IL-6 and TNF-α was up-regulated in TV group ( P<0.05). Compared with TV group, the NSS was significantly decreased, the recognition index was increased, the percentage of freezing time related to context and sound was increased, the number of NeuN-positive cells was increased, the number of IBA1-positive cells was decreased and the cell body area was reduced, the total branch length and intersection points were increased, and the expression of TLR4, MyD88, NF-κB, IL-1β, IL-6 and TNF-α was down-regulated in TD group and TT group ( P<0.05). There was no statistically significant difference in the aforementioned parameters between TD group and TT group ( P>0.05). Conclusions:The mechanism by which dexmedetomidine mitigates TBI-induced cognitive impairment may be related to inhibition of the hippocampal TLR4/MyD88/NF-κB signaling pathway and reduction of neuroinflammatory responses in mice.

Objective:To evaluate the effect of dexmedetomidine on Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor κB (NF-κB) signaling pathway in the hippocampus of mice with cognitive impairment after traumatic brain injury (TBI).Methods:Sixty specific pathogen-free healthy adult wild-type C57BL/6 mice, aged 21-23 months, weighing 28-34 g, were divided into 5 groups ( n=12 each) by a random number table method: sham operation + vehicle group (SV group), sham operation + dexmedetomidine group (SD group), TBI + vehicle group (TV group), TBI + dexmedetomidine group (TD group) and TBI + TLR4 inhibitor TAK-242 group (TT group). The modified Feeney free fall epidural impact method was used to establish a mild TBI model. At 30 min before model preparation, dexmedetomidine 25 μg/kg was intraperitoneally injected in SD group and TD group, TAK-242 10 mg/kg was intraperitoneally injected in TT group, and the equal volume of normal saline was intraperitoneally injected in SV group and TV group. Neurological severity scores (NSSs) were used to evaluate the neurological function at 1, 7 and 14 days after developing the model. The novel object recognition test (recognition index) and fear conditioning test (the percentage of freezing time related to context and sound) were used to evaluate the cognitive function of mice at 16 days after developing the model. The number and morphology of hippocampal neurons (NeuN-positive cells) and activated microglia (ionized calcium-binding adaptor molecule 1[IBA1]-positive cells) were measured by immunofluorescent staining. The expression of interleukin-1beta (IL-1β), IL-6, tumor necrosis factor-alpha (TNF-α), TLR4, MyD88 and nuclear factor kappa B (NF-κB) was detected by Western blot. Results:Compared with SV group, the NSS was significantly increased, the recognition index was decreased, the percentage of freezing time related to context and sound was decreased, the number of NeuN-positive cells was decreased, the number of IBA1-positive cells was increased and the cell body area was enlarged, the total branch length and intersection points were decreased, and the expression of TLR4, MyD88, NF-κB, IL-1β, IL-6 and TNF-α was up-regulated in TV group ( P<0.05). Compared with TV group, the NSS was significantly decreased, the recognition index was increased, the percentage of freezing time related to context and sound was increased, the number of NeuN-positive cells was increased, the number of IBA1-positive cells was decreased and the cell body area was reduced, the total branch length and intersection points were increased, and the expression of TLR4, MyD88, NF-κB, IL-1β, IL-6 and TNF-α was down-regulated in TD group and TT group ( P<0.05). There was no statistically significant difference in the aforementioned parameters between TD group and TT group ( P>0.05). Conclusions:The mechanism by which dexmedetomidine mitigates TBI-induced cognitive impairment may be related to inhibition of the hippocampal TLR4/MyD88/NF-κB signaling pathway and reduction of neuroinflammatory responses in mice.

Objective:To propose a deep learning（DL）-based ultrasound imaging auxiliary tool for automatic segmentation and recognition of the brachial plexus（BP），and to enhance the accuracy and safety of clinical procedures.Methods:It was a multicenter study that collected 773 healthy subjects from Peking University Third Hospital and its branch campuses，the Third Medical Center of the Chinese PLA General Hospital，and Shanghai Eighth People's Hospital between August 2024 and February 2025. Brachial plexus（BP）images in the interscalene groove were captured used high-frequency ultrasound by senior sonographers，a dataset comprising 1 289 standardized images were constructed and the improved model（CHA-TransUNet）was trained. The test set was input into 6 different models（CHA-TransUNet，R50-Unet，TransUnet，SegFormer，SwinUnet，MISSFormer）for segmentation. Segmentation accuracy was evaluated using metrics including the Dice similarity coefficient（DSC），95% Hausdorff distance（HD95）and mean intersection over union（mIoU），and was compared with the segmentation results of 3 ultrasound physicians with varying experience levels（junior physicians and senior physicians）to validate the model's segmentation efficacy.Results:The CHA-TransUNet model established based on a dataset of 1 289 standardized images achieved segmentation results for the BP with a DSC of 90.15%，mIoU of 91.02%，and HD95 of 8.08. Its accuracy was higher than other mainstream models（DSC：90.15% vs. 87.60%，87.77%，81.35%，84.78%，84.55%），significantly better than junior physicians（DSC：90.15% vs. 68.73%， Z=-127.76， P<0.001），and approached the level of senior physician（DSC：90.15% vs. 86.15%， Z=-31.33， P=0.549）. The model demonstrated superior boundary recognition in complex anatomical structures（e.g.，C6/C7 nerve roots）compared to ultrasound physicians（junior and senior）（HD95：8.08 vs. 26.34，17.44，56.80）. Conclusions:This study proposes an analysis model for BP ultrasound images，CHA-TransUNet. This model achieves segmentation and recognition of the BP with relatively complex pathways and structures. The model exhibits high accuracy and stability，outperforming current mainstream network models and junior physicians while approaching the performance level of senior physicians. It assists junior physicians or trainees in more accurately identifying and localizing the BP.

ObjectiveTo screen out the transcriptomes related to the intervention of Wuzi Yanzongwan on the spermatogenic function of semi-castrated male mice， and to explore its potential mechanism in the intervention of the progress of low spermatogenic function. MethodBalb/c mice were randomly divided into sham-operated group， model group， testosterone propionate group（0.2 mg·kg^-1·d^-1， intramuscular injection） and Wuzi Yanzongwan group（1.56 g·kg^-1·d^-1， intragastric administration） according to body weight， with 12 mice in each group. The right testicle and epididymis were extracted from the model group and the drug administration group to construct the semi-castrated model of low spermatogenic function， while the fur and the right scrotum of the sham-operated group were only cut and immediately sterilized and sutured. At the end of the intervention， hematoxylin-eosin（HE） staining was used to observe the histopathology of testis， enzyme-linked immunosorbent assay（ELISA） was used to detect the levels of serum testosterone（T）， luteinizing hormone（LH） and follicle stimulating hormone（FSH）. The sperm count and motility of epididymis were measured by automatic sperm detector of small animal. Transcriptomic microarray technology was used to detect the mRNA expression level of testicular tissue in each group， the transcriptome of genes related to the regulation of Wuzi Yanzongwan was screened， and three mRNAs were selected for Real-time fluorescence quantitative polymerase chain reaction（Real-time PCR） to verify the transcriptome data. Through the annotation analysis of Gene Ontology（GO） and the signaling pathway analysis of Kyoto Encyclopedia of Genes and Genomes（KEGG）， the related functions of drugs regulating transcriptome were analyzed. ResultCompared with the sham-operated group， the testicular tissue of mice in the model group showed spermatogenic injury， contraction and vacuolization of the seminiferous tubules， reduction of spermatogenic cells at all levels， widening of the interstitial space， obstruction of spermatogonial cell development and other morphological abnormalities， and serum T significantly decreased， LH significantly increased（P<0.01）， and FSH elevated but no statistically significant difference， the count and vitality of epididymal sperm significantly decreased（P<0.01）. There were 882 differentially expressed mRNAs in the testicular tissues， of which 565 were up-regulated and 317 were down-regulated. Cluster analysis showed that these differentially expressed mRNA could effectively distinguish between the sham-operated group and the model group. Compared with the model group， the damage to testicular tissue in the Wuzi Yanzongwan group was reduced， the structure of the seminiferous tubules was intact， vacuolization was reduced， and the number of spermatogenic cells at all levels was significantly increased and arranged tightly. The serum T significantly increased， LH significantly decreased（P<0.01）， and FSH decreased but the difference was not statistically significant. The count and vitality of sperm in the epididymis were significantly increased（P<0.01）. Moreover， Wuzi Yanzongwan could regulate 159 mRNA levels in the testes of semi-castrated mice， of which 32 were up-regulated and 127 were down-regulated， and the data of the transcriptome assay was verified to be reliable by Real-time PCR. GO and KEGG analysis showed that the transcriptome functions regulated by Wuzi Yanzongwan were involved in the whole cell cycle process of sperm development such as sex hormone production of interstitial cells in testis， renewal， differentiation， metabolism， apoptosis and signal transduction of spermatogenic cells， and were closely related to the biological behaviors of signaling pathways such as spermatogenic stem cell function， endoplasmic reticulum protein processing and metabolic program. ConclusionWuzi Yanzongwan can effectively improve the low spermatogenic function of semi-castrated male mice， and its mechanism may be related to the regulation of testicular transcriptional regulatory network， the synthesis of sex hormones in testicular interstitial cells， the function of spermatogenic stem cells， the whole cell cycle process of spermatogenesis， as well as the expression of endoplasmic reticulum protein processing and metabolic program related genes transcription.

Objective:To investigate the effects of fluoride exposure on kidney injury in rats and the sirtuin 3 (SIRT3)-fork head protein O3a (FOXO3a)-tensin homolog induced putative kinase 1 (PINK1)/E3 ubiquitin ligase (PARKIN) pathway.Methods:Twenty-four 4-week-old SD rats (clean grade, body mass 100 - 150 g) were selected and divided into three groups according to the randomized numeric table: control group, low fluoride group, and high fluoride group, with eight rats in each group (half male and half female). The control group was given free access to tap water (fluoride ion concentration < 0.5 mg/L), while the low fluoride and high fluoride groups were given free access to tap water and sodium fluoride solutions with fluoride ion concentrations of 5.0 and 50.0 mg/L, respectively, for a period of 180 days. The formation of dental fluorosis in rats was observed and recorded, and the femur, urine and blood samples of rats were collected to measure bone fluoride, urinary fluoride, and blood fluoride levels, and to detect kidney function related indicators (serum uric acid, creatinine, and urea nitrogen contents). Morphological changes of renal tissues stained with hematoxylin-eosin (HE) were observed under a light microscope. Real-time fluorescence quantitative PCR (qRT-PCR) and Western blotting were used to detect the mRNA and protein expression levels of renal SIRT3, FOXO3a, PINK1, PARKIN, microtubule associated protein 1 light chain 3 (LC3), autophagy receptor protein (P62), respectively.Results:Seven and one rats in the low and high fluoride groups were found to haveⅠdegree dental fluorosis, while zero and seven rats were found to haveⅡdegree dental fluorosis. Compared with the control group, rats in the low and high fluoride groups had higher levels of bone fluoride (μg/g: 1.18 ± 0.06, 2.16 ± 0.07 vs 0.52 ± 0.05), urinary fluoride (mg/L: 4.43 ± 0.11, 7.46 ± 0.09 vs 2.58 ± 0.14), blood fluoride (μg/ml: 0.77 ± 0.06, 1.68 ± 0.10 vs 0.52 ± 0.08), serum uric acid (μg/ml: 61.01 ± 4.17, 103.92 ± 5.43 vs 28.68 ± 2.91), creatinine (μg/ml: 74.82 ± 9.61, 132.05 ± 5.35 vs 22.38 ± 4.11), and urea nitrogen (μg/ml: 13.36 ± 1.27, 14.55 ± 0.34 vs 0.29 ± 0.07, P < 0.05). Under the light microscope, the kidneys of the control group showed tight and orderly arrangement of renal tubules and glomerular cells, with complete and clear cell contours. The low fluoride group was similar to the control group and no significant abnormalities were observed. The high fluoride group showed abnormal glomerular structure and atrophy, with some areas of renal tubules showing epithelial cell edema and unclear intercellular boundaries. The results of qRT-PCR assay showed that compared with the control group, the low and high fluoride groups had lower mRNA expression levels of SIRT3 (0.82 ± 0.03, 0.58 ± 0.02 vs 1.00 ± 0.08), P62 (0.75 ± 0.07, 0.28 ± 0.09 vs 1.00 ± 0.07, P < 0.05), and higher mRNA expression levels of FOXO3a (1.35 ± 0.04, 3.01 ± 0.23 vs 1.00 ± 0.08), PINK1 (1.58 ± 0.09, 3.28 ± 0.09 vs 1.00 ± 0.07), PARKIN (1.51 ± 0.04, 1.67 ± 0.10 vs 1.00 ± 0.05), LC3 (1.74 ± 0.07, 2.38 ± 0.18 vs 1.00 ± 0.08, P < 0.05). The results of Western blotting showed that compared with the control group, the low and high fluoride groups had lower protein expression levels of SIRT3 (0.91 ± 0.01, 0.55 ± 0.03 vs 1.00 ± 0.01), P62 (0.94 ± 0.27, 0.66 ± 0.38 vs 1.00 ± 0.19, P < 0.05), and higher protein expression levels of FOXO3a (1.14 ± 0.03, 1.22 ± 0.05 vs 1.00 ± 0.02), PINK1 (1.46 ± 0.03, 1.56 ± 0.03 vs 1.00 ± 0.05), PARKIN (1.98 ± 0.02, 2.33 ± 0.11 vs 1.00 ± 0.06), LC3 (4.10 ± 0.58, 4.93 ± 0.33 vs 1.00 ± 0.13, P < 0.05). Conclusion:Exposure to fluoride can cause renal tissue injury in rats, with downregulation of SIRT3 and P62 expression levels, and upregulation of FOXO3a, PINK1, PARKIN, and LC3 expression levels.

Objective To observe the effect of dapagliflozin on cardiac function in patients with heart failure after emergency percutaneous transluminal coronary intervention in acute ST segment elevation myocardial infarction. Methods A total of 100 patients with acute myocardial infarction underwent emergency PCI were randomly divided into study group (52 cases) and control group (48 cases). The study group was given dapagliflozin on the basis of standardized treatment of myocardial infarction, and the control group was given conventional treatment of myocardial infarction. Cardiac ultrasound related indexes[left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular end-diastolic volume (LVEDV)], plasma N-terminal brain natriuretic peptide (NT-proBNP) level, 6-minute walking test (6MWT) results. The incidence of adverse reactions and major cardiovascular adverse events (MACE) were compared between the two groups during follow-up. Results After 6 months of treatment, LVESD, LVEDD and LVEDV in the two groups were significantly lower than before treatment, and LVEF was significantly higher than before treatment (P < 0.05); the LVESD, LVEDD and LVEDV of the study group were significantly lower than those of the control group, and LVEF was significantly higher than that of the control group (P < 0.05). The NT-proBNP in the two groups was significantly lower than before treatment, and was significantly lower in the study group than that in the control group (P < 0.05). The 6MWT distance of the study group was significantly longer than that of the control group (P < 0.05). There was no significant difference in the incidence of adverse reactions and MACE between the two groups (P>0.05). Conclusion Dapagliflozin can improve cardiac function in patients with heart failure after emergency PCI of acute ST segment elevation myocardial infarction.

Renal abscess caused by fish bone ingestion is extremely rare and has not been reported in the literature. A male patient presented with a 1-week history of flank pain and a 2-day history of fever. Urinary ultrasound and CT scan showed an irregular hypodense lesion in the left kidney and blurred thickening of the descending colon wall. Three-dimensional CT reconstruction images revealed a needle-like foreign body, which perforated from the descending colonic lumen to the left kidney. The patient had accidentally eaten fish bone one week prior. On the basis of clinical data, the diagnosis of renal abscess caused by foreign body was suspected. Accordingly, laparotomy was performed, the abscess was drained, and the colon was repaired. The foreign body was confirmed to be fish bone. The postoperative condition of the patient was uneventful, and the patient remained well in the 3 months' follow-up without any further complaints.

Objective:To investigate the early and middle term clinical efficacies of 3D-printed metal prostheses in the reconstruction of bone defects after osteotomy in malignant bone tumors.Methods:A total of 34 patients with malignant bone tumors of lower extremity femur and tibia who underwent 3D printing individualized metal prosthesis replacement surgery in the Department of Bone and Soft Tissue of Affiliated Cancer Hospital of Zhengzhou University from March 2019 to March 2022 were retrospectively analyzed. There were 23 males and 11 females, with an average age of 19.1±15.2 years (range, 7-80 years). There were 22 children and adolescents younger than 18 years old. There were 3 cases in the proximal femur, 15 cases in the middle and distal femur, 10 cases in the proximal tibia and 6 cases in the distal tibia. According to the final pathological diagnosis, 24 cases of osteosarcoma, 6 cases of Ewing's sarcoma, 2 cases of undifferentiated sarcoma, 1 case of osteosarcoma, and 1 case of malignant giant cell tumor of bone were enrolled in this study. Postoperative complications, wound healing, periprosthetic fracture and aseptic loosening, tumor outcome (evaluated by tumor control evaluation criteria), and length difference of lower limbs were recorded. Response evaluation criteria in solid tumor (RECIST) was used to evaluate tumor outcomes. Prosthetic-bone interface healing was evaluated postoperatively, and the function was evaluated based on Musculoskeletal Oncology Society (MSTS) 93.Results:The length of lesions was 70-240 mm in 34 patients, with an average of 125.5±35.4 mm. The length of osteotomy was 80-275 mm, with an average of 160.2±33.9 mm. No tumor was found on the osteotomy surface. The customized prosthesis was firmly installed and closely matched with the side of the preserved articular surface. There were 2 patients with local incision fat liquefaction and 4 patients with superficial wound infection, which healed after debridement and antibiotic treatment. One distal tibia osteosarcoma case developed severe periprosthetic infection 2 months after surgery, resulting in prosthesis implantation failure, limb movement pain and poor ankle function. After removal of the prosthesis, infection control and osteogenesis with the Ilizarov technique, the infection was completely controlled and local osteogenesis was possible. The remaining 33 patients had a good prosthetic-bone interface union. One case was found to have localized bone resorption on the contact surface of the prosthesis 7 months after operation, but the metal prosthesis and screws were not loose. The incisions healed well in other patients, without infection, prosthesis loosening, fracture or other complications. All patients survived and were followed up for 13.8±5.6 months (range, 7-27 months). During the follow-up, there was no recurrence of tumor at the osteotomy end in all patients, but 5 patients developed lung metastasis. At the end of the last follow-up, all patients survived. Among them, 16 patients had unequal length of lower limbs, including 10 cases within 2 cm, 3 cases between 2-5 cm, and 3 cases over 5 cm. With the exception of one patient whose prosthesis was removed due to infection, the MSTS 93 of the other patients was 24.9±2.2 (range, 19-28), and were rated as excellent in 26 cases and good in 7 cases. According to the RECIST evaluation criteria, 26 of 34 patients had complete response, 5 had disease progression, and 3 had stable disease.Conclusion:3D printed metal prosthesis is one of the effective methods for the treatment of bone defects after resection of malignant bone tumors in lower limbs, which is safe, reliable and has satisfactory early curative effect.