OBJECTIVE: To identify the role of gene silencing or overexpression of Nemo-like kinase (NLK) during the process of neural differentiation of human mesenchymal stem cells (hBMSCs), and to explore the effect of NLK downregulation by transfection of small interfering RNA (siRNA) on promoting neuralized tissue engineered bone regeneration. METHODS: NLK-knockdown hBMSCs were established by transfection of siRNA (the experimental group was transfected with siRNA silencing the NLK gene, the control group was transfected with control siRNA and labeled as negative control group), and NLK-overexpression hBMSCs were established using lentivirus vector transfection technique (the experimental group was infected with lentivirus overexpressing the NLK gene, the control group was infected with an empty vector lentivirus and labeled as the empty vector group). After neurogenic induction, quantitative real-time polymerase chain reaction (qPCR) was used to detect the expression of neural-related gene, and Western blot as well as immunofluorescence staining about several specific neural markers were used to evaluate the neural differentiation ability of hBMSCs.6-week-old male nude mice were divided into 4 groups: ① β-tricalcium phosphate (β-TCP) group, ② β-TCP+ osteogenic induced hBMSCs group, ③ β-TCP+ siRNA-negative control (siRNA-NC) transfection hBMSCs group, ④ β-TCP+ siRNA-NLK transfection hBMSCs group. Four weeks after the subcutaneous ectopic osteogenesis models were established, the osteogenesis and neurogenesis were detected by hematoxylin-eosin (HE) staining, Masson staining and tissue immunofluorescence assay. Statistical analysis was conducted by independent sample t test. RESULTS: After gene silencing of NLK by siRNA in hBMSCs, neural-related genes, including the class Ⅲ β-tubulin (TUBB3), microtubule association protein-2 (MAP2), soluble protein-100 (S100), nestin (NES), NG2 proteoglycan (NG2) and calcitonin gene-related peptide (CGRP), were increased significantly in NLK-knockdown hBMSCs compared with the negative control group(P < 0.05), and the expression levels of TUBB3 and MAP2 of the NLK silencing group were also increased. Oppositely, after NLK was overexpressed using lentivirus vector transfection technique, TUBB3, MAP2, S100 and NG2 were significantly decreased in NLK-overexpression hBMSCs compared with the empty vector group (P < 0.05), and the expression level of TUBB3 was also decreased. 4 weeks after the subcutaneous ectopic osteogenesis model was established, more mineralized tissues were formed in the β-TCP+ siRNA-NLK transfection hBMSCs group compared with the other three groups, and the expression of BMP2 and S100 was higher in the β-TCP+ siRNA-NLK transfection hBMSCs group than in the other groups. CONCLUSION Gene silencing of NLK by siRNA promoted the ability of neural differentiation of hBMSCs in vitro and promoted neuralized tissue engineered bone formation in subcutaneous ectopic osteogenic models in vivo in nude mice.
Bone Regeneration/genetics* ; Animals ; Mesenchymal Stem Cells/cytology* ; Humans ; RNA, Small Interfering/genetics* ; Tissue Engineering/methods* ; Cell Differentiation ; Mice, Nude ; Gene Silencing ; Mice ; Male ; Protein Serine-Threonine Kinases/genetics* ; Intracellular Signaling Peptides and Proteins/genetics* ; Transfection ; Cells, Cultured ; Lentivirus/genetics*

OBJECTIVE: To investigate the biocompatibility of porous WE43 magnesium alloy scaffolds manufactured by 3D printing technology and to observe its effect in treating femoral defects in New Zealand white rabbits. METHODS: In vitro cytotoxicity test was performed using bone marrow mesenchymal stem cells from Sprague Dawley (S-D) rats. According to the different culture media, the cells were divided into 100% extract group, 50% extract group, 10% extract group and control group. After culturing for 1, 3 and 7 days, the cell activity of each group was determined by cell counting kit-8 (CCK-8). In the in vivo experiment, 3.0-3.5 kg New Zealand white rabbits were randomly divided into three groups: Experimental group, bone cement group and blank group, with 9 rabbits in each group. Each rabbit underwent surgery on the left lateral femoral condyle, and a bone defect with a diameter of 5 mm and a depth of 6 mm was created using a bone drill. The experimental group was implanted with WE43 magnesium alloy scaffolds, the bone cement group was implanted with calcium sulfate bone cement, and the blank group was not implanted. Then 4, 8 and 12 weeks after surgery, 3 rabbits in each group were euthanized by carbon dioxide anesthesia, and the femur and important internal organs were sampled. Micro-computed tomography (Micro-CT) scanning was performed on the left lateral femoral condyle. Sections of important internal organs were prepared and stained with hematoxylin-eosin (HE). Hard tissue sections were made from the left lateral femoral condyle and stained with methylene blue acid fuchsin and observed under a microscope. RESULTS: In the cytotoxicity test, the cell survival rate in the 100% extract group was higher than that in the control group (140.56% vs. 100.00%, P < 0.05) on 1 day of culture; there was no statistically significant difference (P>0.05) in cell survival rate among the groups on 3 days of culture; the cell survival rate in the 100% extract group was lower than that in the control group (68.64% vs. 100.00%, P < 0.05) on 7 days of culture. Micro-CT scanning in the in vivo experiment found that most of the scaffolds in the experimental group had been degraded in 4 weeks, with very few high-density scaffolds remaining. In 12 weeks, there was no obvious stent outline. In 4 weeks, a certain amount of gas was generated around the WE43 magnesium alloy scaffold, and the gas was significantly reduced from 8 to 12 weeks. Hard tissue sections showed that a certain amount of extracellular matrix and osteoid were generated around the scaffolds in the experimental group in 4 weeks. In the bone cement group, most of the calcium sulfate bone cement had been degraded. In 8 weeks, the osteoid around the scaffold and its degradation products in the experimental group increased significantly. In 12 weeks, new bone was in contact with the scaffold around the scaffold in the experimental group. There was less new bone in the bone cement group and the blank group. CONCLUSION The porous WE43 magnesium alloy scaffold fabricated by 3D printing process has good biocompatibility and good osteogenic properties, and has the potential to become a new material for repairing bone defects.
Animals ; Rabbits ; Printing, Three-Dimensional ; Alloys/chemistry* ; Tissue Scaffolds/chemistry* ; Magnesium/chemistry* ; Rats, Sprague-Dawley ; Biocompatible Materials ; Mesenchymal Stem Cells/cytology* ; Femur/surgery* ; Rats ; Absorbable Implants ; Male ; Bone Regeneration ; Tissue Engineering/methods* ; Cells, Cultured

OBJECTIVE: To evaluate the filling quality of single cone obturation in root canal model with irregular structure (Hus&Kim Ⅴ, Yin Ⅱ-type isthmus) which established by 3D printing technology using slices and radiographic methods, in order to provide reference for clinical practice. METHODS: (1) Extracted fresh premolars with Hus&Kim Ⅴ and Yin-type Ⅱ isthmus were collected and scanned by cone-beam computed tomography (CBCT), then standard root canal models were designed and printed. Rhodamine B staining and bias fitting were used to verify the availability of the models. (2) 30 root canal models were randomly divided into 3 groups according to different filling methods (n=10). CONTROL GROUP: vertical compaction obturation; Experimental group 1: single cone obturation with 0.06-taper cone (30#); Experimental group 2: single cone obturation with 0.04-taper cone (35#), GuttaFlow 2 as canal sealers. Slices were taken at 2, 4, 6, and 8 mm from the root apex in the direction perpendicular to the long axis of the root and observed under a stereomicroscope to calculate the percentage of filling area (PAV), percentage of gutta-percha-filled area (PGFA), percentage of sealer filled area (PSFA). (3) On the basis of the above results, two groups (n=4) were selected to further analyze the filling quality by micro-computed tomography (Micro-CT), the filling volume of main root canal and the isthmus were obtained, and the percentage of filling volume (PFV) was calculated. Two-way ANOVA was used to evaluate the differences between the groups, and Tukey' s multiple comparison was used to compare the data between the groups and within the groups. RESULTS: (1) Rhodamine B staining solution could overflow the apical foramen, and the main root canal system and the isthmus area were stained, showed no remnants of support material. The 3D standard deviation of the printed model data was 0.03 mm, and the average fitting distance was 0.02 mm. (2) The PFA of the two experimental groups were both significantly lower than that of the control group (F=45.04, P < 0.01). There was no statistical difference of the PFA at apical 2 and 4 mm between the two experimental groups (P>0.01), but at the middle and coronal portions of the root canal (6, 8 mm), the PFA of the experimental group 1 was higher than that of the experimental group 2 (P < 0.01). PFA in the apical 2, 4 mm of the two experimental groups were both lower than that in the middle and coronal portions 6, 8 mm of the canal (P < 0.01). There was no difference in the PGFA and PSFA between the two experimental groups at the apical 2, 4 mm (F=2.383, P>0.01). (3) The results of Micro-CT showed that the PFV of the experimental group 1 was statistically different with the control group (F=47.33, P < 0.01). The PFV of the experimental group 1 was 54.33%±4.35% in the isthmus and 78.31%±4.21% in the main root canal, which were both lower than the PFV of the control group of 76.48%±4.89% (isthmus) and 86.90%±3.29% (main root canal, P < 0.01). The PFV of the main root canal in the experimental group 1 was higher than that in the isthmus (P < 0.01), while there was no difference between the isthmus and the main root canal in the control group (P>0.01). CONCLUSION In the irregular root canal structure with isthmus, using large-taper gutta-percha can improve the filling quality of the middle and upper part of the canal, but the percentage of filling volume in the isthmus is lower than that of the main canal, and more technical improvements are needed.
Humans ; Root Canal Obturation/methods* ; Cone-Beam Computed Tomography ; Root Canal Filling Materials ; Dental Pulp Cavity/diagnostic imaging* ; Printing, Three-Dimensional ; In Vitro Techniques ; Gutta-Percha ; Bicuspid

OBJECTIVE: To standardize the operative procedure for tissue-engineered cartilage repair, by demonstrating surgical technique of arthroscopic implantation of decalcified cortex-cancellous bone scaffolds, and summarizing the surgical experience of the sports medicine department team at Peking University Third Hospital. METHODS: This article elaborates on surgical techniques and skills, focusing on the unabridged implantation technology and surgical procedure of decalcified cortex-cancellous bone scaffolds under arthroscopy: First, the patient was placed in the supine position. After anesthesia had been established, the surgeon established an arthroscope and explored the damaged area under the scope. After confirming the size and location of the injury site, the surgeon cleaned the damaged cartilage, and also trimmed the edges of the cartilage to ensure that the cut surface was smooth and stable. the surgeon performed the micro-fracture surgery in the area of cartilage injury, and then measured the size of the injured area under the scope. Next, the surgeon manually trimmed the tissue-engineered scaffold based on the measurements taken under the arthroscope, and then directly implanted the scaffold using a sleeve. A honeycomb-shaped fixator was used to implant absorbable nails to fix the scaffold. After the scaffold was installed, the knee was repeatedly flexed and extended for 10-20 times to ensure stability and range of motion. Finally, the arthroscope was withdrawn and the wound was closed. RESULTS: Decalcified cortex-cancellous bone scaffolds possessed unparalleled advantages over synthetic materials in terms of morphology and biomechanics. The cancellous bone part of the scaffold provided a three-dimensional, porous space for cell growth, while the cortical bone part offered the necessary mechanical strength. The surgery was performed entirely under arthroscopy to minimize invasiveness to the patient. Absorbable pins were used for fixation to ensure the stability of the scaffold. This technique could effectively improve the prognosis of the patients with cartilage injuries and standardized the surgical procedures for arthroscopic tissue-engineered scaffold operations in the patients with cartilage damage. CONCLUSION With the standard arthroscopic tissue-engineered scaffold repair technique, it is possible to successfully repair damaged cartilage, alleviate symptoms in the short term, and provide a more ideal long-term prognosis. The author and their team explain the surgical procedures for tissue-engineered scaffolds under arthroscopy, with the aim of guiding future clinical practice.
Tissue Engineering/methods* ; Humans ; Tissue Scaffolds ; Arthroscopy/methods* ; Cartilage, Articular/surgery*

As representatives of the third generation of biomedical materials, hydrogels exhibit revolutionary potential in tissue engineering, precision drug delivery, and smart medical devices due to their ability to construct bionic microenvironments. However, the clinical translation of hydrogels is still limited by multidimensional challenges, including biocompatibility, scalable production, and regulatory complexity. This paper systematically reviews the design innovations, functionalization strategies, and translational bottlenecks of hydrogel materials, integrates the latest technological trends, such as 4D printing and AI-driven design, and proposes a collaborative optimization pathway encompassing materials, technology, clinical applications, and policy. By introducing local Chinese innovation cases and monitoring scientific advancements, this study offers solutions that possess both academic significance and practical guidance for the clinical translation of hydrogels.
Hydrogels ; Tissue Engineering ; Translational Research, Biomedical ; Biocompatible Materials ; Humans ; Drug Delivery Systems

Collagen membrane has attracted much attention from researchers due to its excellent properties such as wide source, degradable absorption, and low immunogenicity. However, they are limited by poor mechanical stability and rapid degradation. To enhance their physicochemical properties and biological functions, researchers have developed various strategies, including cross-linking, incorporation of growth factors or drugs, combination with other biomaterials, optimization of composition and structure, and substitution with marine-derived collagen. These advances aim to expand the clinical applications of collagen membranes in oral medicine. With the urgent demand for high-performance biomaterials in oral medicine, summarizing recent progress on collagen membranes provides valuable insights into their mechanisms, clinical efficacy, and limitations, offering reference for optimized design and broader clinical use. Furthermore, further trends may include integrating advanced manufacturing technologies to develop personalized collagen membranes, which could significantly improve therapeutic outcomes in oral diseases.
Collagen/therapeutic use* ; Humans ; Biocompatible Materials/chemistry* ; Membranes, Artificial ; Oral Medicine/methods* ; Tissue Engineering/methods*

Bone repair remains an important target in tissue engineering, making the development of bioactive scaffolds for effective bone defect repair a critical objective. In this study, β-tricalcium phosphate (β-TCP) scaffolds incorporated with processed pyritum decoction (PPD) were fabricated using three-dimensional (3D) printing-assisted freeze-casting. The produced composite scaffolds were evaluated for their mechanical strength, physicochemical properties, biocompatibility, in vitro pro-angiogenic activity, and in vivo efficacy in repairing rabbit femoral defects. They not only demonstrated excellent physicochemical properties, enhanced mechanical strength, and good biosafety but also significantly promoted the proliferation, migration, and aggregation of pro-angiogenic human umbilical vein endothelial cells (HUVECs). In vivo studies revealed that all scaffold groups facilitated osteogenesis at the bone defect site, with the β-TCP scaffolds loaded with PPD markedly enhancing the expression of neurogenic locus Notch homolog protein 1 (Notch1), vascular endothelial growth factor (VEGF), bone morphogenetic protein-2 (BMP-2), and osteopontin (OPN). Overall, the scaffolds developed in this study exhibited strong angiogenic and osteogenic capabilities both in vitro and in vivo. The incorporation of PPD notably promoted the angiogenic-osteogenic coupling, thereby accelerating bone repair, which suggests that PPD is a promising material for bone repair and that the PPD/β-TCP scaffolds hold great potential as a bone graft alternative.
Calcium Phosphates/chemistry* ; Animals ; Bone Regeneration ; Rabbits ; Tissue Scaffolds ; Printing, Three-Dimensional ; Humans ; Human Umbilical Vein Endothelial Cells ; Neovascularization, Physiologic ; Osteogenesis ; Tissue Engineering/methods* ; Biomimetic Materials ; Cell Proliferation ; Angiogenesis

Osteosarcoma (OS), chondrosarcoma (CS), and Ewing sarcoma (ES) represent primary malignant bone tumors and pose significant challenges in oncology research and clinical management. Conventional research methods, such as two-dimensional (2D) cultured tumor cells and animal models, have limitations in recapitulating the complex tumor microenvironment (TME) and often fail to translate into effective clinical treatments. The advancement of three-dimensional (3D) culture technology has revolutionized the field by enabling the development of in vitro constructed bone tumor models that closely mimic the in vivo TME. These models provide powerful tools for investigating tumor biology, assessing therapeutic responses, and advancing personalized medicine. This comprehensive review summarizes the recent advancements in research on 3D tumor models constructed in vitro for OS, CS, and ES. We discuss the various techniques employed in model construction, their applications, and the challenges and future directions in this field. The integration of advanced technologies and the incorporation of additional cell types hold promise for the development of more sophisticated and physiologically relevant models. As research in this field continues to evolve, we anticipate that these models will play an increasingly crucial role in unraveling the complexities of malignant bone tumors and accelerating the development of novel therapeutic strategies.
Bone Neoplasms/pathology* ; Humans ; Osteosarcoma/pathology* ; Tumor Microenvironment ; Sarcoma, Ewing/pathology* ; Chondrosarcoma/pathology* ; Animals ; Cell Culture Techniques/methods* ; Cell Culture Techniques, Three Dimensional/methods* ; Cell Line, Tumor

Macrophages derived from the human THP-1 cell line have been widely used as substitutes for primary macrophages in various macrophage-related studies. However, difficulties still exist in establishing THP-1 macrophage models. This research presents techniques for generating different phenotypes of activated macrophages derived from THP-1 cells by introducing specific stimuli and provides some potential markers to confirm each type of activated macrophage. It is hoped to provide novel and useful methods for scientific research and to help researchers explore this field more intuitively and effectively.
Humans ; Macrophages/physiology* ; THP-1 Cells ; Cell Culture Techniques/methods* ; Macrophage Activation ; Cell Polarity ; Cell Differentiation ; Phenotype ; Cell Line

OBJECTIVES: To investigate the mechanism by which transforming growth factor‑β (TGF‑β) regulates major histocompatibility complex class I (MHC-I) expression in hepatocellular carcinoma (HCC) cells and its role in immune evasion of HCC. METHODS: HCC cells treated with TGF‑β alone or in combination with SB-431542 (a TGF-β type I receptor inhibitor) were examined for changes in MHC-I expression using RT-qPCR and Western blotting. A RNA interference experiment was used to explore the role of miR-23a-3p/IRF1 signaling in TGF‑β‑mediated regulation of MHC-I. HCC cells with different treatments were co-cultured with human peripheral blood mononuclear cells (PBMCs), and the changes in HCC cell proliferation was assessed using CCK-8 and colony formation assays. T-cell cytotoxicity in the co-culture systems was assessed with lactate dehydrogenase (LDH) release and JC-1 mitochondrial membrane potential assays, and T-cell activation was evaluated by flow cytometric analysis of CD69 cells and ELISA for TNF-α secretion. RESULTS: TGF‑β treatment significantly suppressed MHC-I expression in HCC cells and reduced T-cell activation, leading to increased tumor cell proliferation and decreased HCC cell death in the co-culture systems. Mechanistically, TGF-β upregulated miR-23a-3p, which directly targeted IRF1 to inhibit MHC-I transcription. Overexpression of miR-23a-3p phenocopied TGF‑β‑induced suppression of IRF1 and MHC-I. CONCLUSIONS We reveal a novel immune escape mechanism of HCC, in which TGF‑β attenuates T cell-mediated antitumor immunity by suppressing MHC-I expression through the miR-23a-3p/IRF1 signaling axis.
Humans ; MicroRNAs/genetics* ; Carcinoma, Hepatocellular/metabolism* ; Liver Neoplasms/metabolism* ; Interferon Regulatory Factor-1/metabolism* ; Transforming Growth Factor beta/metabolism* ; Signal Transduction ; Histocompatibility Antigens Class I/metabolism* ; Cell Line, Tumor ; Tumor Escape ; Coculture Techniques