BACKGROUND:In recent years,artificial intelligence has gradually emerged and has been applied in various fields such as spinal cord nerve injury and repair,which has a positive impact on clinical treatment. OBJECTIVE:To study the application progress of artificial intelligence in the diagnosis,treatment,and rehabilitation of spinal cord nerve injury and repair,clarify the research hotspots and shortcomings in this field,and provide suggestions for future research work. METHODS:Relevant literature on artificial intelligence in the field of spinal cord nerve injury and repair was retrieved on the Web of Science core collection database until 2023.CiteSpace 6.1.R6 and VOSviewer 1.6.19 software was used to perform general literature analysis,co-citation of literature,co-citation of journals,double image overlay of journals,keyword clustering,and other visual analysis on the literature data. RESULTS AND CONCLUSION:(1)A total of 1 713 articles were selected,and the annual publication volume in this field showed a fluctuating upward trend,with the United States taking the lead,and Kadone and Hideki being the authors with the highest publication volume.ARCH PHYS MED REHAB was the journal with the highest number of citations.(2)Keyword co-occurrence and cluster analysis showed that after removing keywords similar to the search terms,the main keywords were divided into three main clusters:Exoskeleton and exercise rehabilitation(the largest core hotspot);machine learning and neural plasticity;robotics and rehabilitation training.(3)Keyword burst analysis showed that deep learning and artificial intelligence had become burst terms in the past five years.(4)The results of in-depth analysis of co cited and highly cited literature showed that the hotspots of artificial intelligence in the field of spinal cord nerve injury and repair were mainly focused on powered exoskeletons,gaits,electrical nerve stimulation,intracortical brain-computer interface(IBCI),robots,and polymer biomaterials,and neural stem cell.(5)The research on artificial intelligence in the field of spinal cord nerve injury and repair has shown an upward trend in recent years.The focus of this field had gradually shifted from single treatment methods such as exoskeletons and electrical stimulation to intelligent,precise,and personalized directions.(6)There were some limitations in this field,such as the consequences of missing or imbalanced data,low data accuracy and reproducibility,and ethical issues(such as privacy,research transparency,and clinical reliability).Future research should address the issue of data collection,requiring large sample,high-quality clinical datasets to establish effective artificial intelligence models.At the same time,the research on genomics and other mechanisms in this field is very weak.In the future,various machine learning technologies such as brain chips can be used,and gene editing therapy,single-cell spatial transcriptome and other methods can be used to study the basic mechanisms of regeneration-related gene upregulation and axon growth structural protein production.

BACKGROUND:During healing process of chronic wounds,excessive production of reactive oxygen species can impair the function of L929 fibroblasts,thereby delaying wound repair.Therefore,protecting fibroblasts from oxidative stress is important to promote wound healing. OBJECTIVE:To assess the protective effects of carboxymethyl chitosan-oxidized chondroitin sulfate/platelet-rich plasma(CMC-OCS/PRP)hydrogel on L929 cells under H2O2 stimulation. METHODS:CMC-OCS/PRP hydrogels were prepared,and the micromorphology,degradation performance,scavenging ability of H2O2 and hydroxyl radical and biocompatibility of the hydrogels were characterized.L929 cells with good growth state were taken and cultured in five groups.The control group was cultured conventionally.H2O2 was added to the H2O2 group.Carboxymethyl chitosan-oxidized chondroitin sulfate hydrogel extract+H2O2 was added to the CMC-OCS group.Platelet-rich plasma gel extract+H2O2 was added to the PRP group.The CMC-OCS/PRP group was treated with carboxymethyl chitosan-oxidized chondroitin sulfate/platelet-rich plasma hydrogel extract+H2O2.Each group was treated with hydrogel extract for 6 hours,and then H2O2 for 24 hours.After culture,the levels of active oxygen and malondialdehyde,apoptosis and expression of collagen fiber I protein were detected.In the presence of H2O2,the above hydrogel extracts were directly or indirectly co-cultured with L929 fibroblasts for 36 hours,respectively.Migration ability of the cells was detected by scratch test and Transwell chamber test. RESULTS AND CONCLUSION:(1)CMC-OCS/PRP hydrogels had uniform and interrelated porous structure and good degradation ability,could effectively remove H2O2 and hydroxyl radicals in vitro,and had good biocompatibility.(2)Compared with the control group,the apoptosis rate,reactive oxygen species,and malondialdehyde levels were increased(P<0.05);the spread area of cells was decreased(P<0.05),and the expression of collagen fiber I protein had no significant changes(P>0.05)in the H2O2 group.Compared with the H2O2 group,reactive oxygen species level was decreased in the CMC-OCS group(P<0.05),malondialdehyde level was decreased(P<0.05),and cell spread area was increased(P<0.05)in the PRP group,CMC-OCS group,and CMC-OCS/PRP group;apoptosis rate was decreased in the CMC-OCS/PRP group(P<0.05),and collagen fiber I protein expression was increased in the PRP group,CMC-OCS group,and CMC-OCS/PRP group(P<0.05).(3)Compared with the control group,the number of cell migration was decreased(P<0.05),and the migration area had no significant change(P>0.05)in the H2O2 group.Compared with the H2O2 group,the number and area of cell migration were increased in the PRP group,CMC-OCS group,and CMC-OCS/PRP group(P<0.05),and the increase was most significant in the CMC-OCS/PRP group.(4)Under oxidative stress,CMC-OCS/PRP hydrogel can improve the migration ability of fibroblasts,resist cell apoptosis,and preserve cell extension function.

BACKGROUND:Precision therapy based on multifunctional nanomaterials is a novel therapeutic model for malignancies that can integrate multiple imaging and therapeutic models into one nanoscale platform to achieve visual combination treatment. OBJECTIVE:To prepare novel nanoparticles loaded with Cu2(OH)PO4 nanoparticles(CuNPs)and nuciferine(NF)(h-PCuNF),and to explore their ability to mediate combined photothermal therapy/photodynamic therapy/chemodynamic therapy/chemotherapy for malignancy. METHODS:The h-PCuNF nanoparticles were synthesized through a double-emulsion procedure,through which the CuNPs and NF were loaded into the shell of hollow poly(lactic-co-glycolic)acid nanocarriers.The morphology,structure,particle size,and zeta potential of the h-PCuNF nanoparticles were characterized.In deionized water,the magnetic resonance imaging and photothermal conversion performances of the h-PCuNF nanoparticles,as well as their capability to implement reactive oxygen species production by mediating photocatalysis and Fenton-like reactions,were evaluated.In liver malignant tumor cell line HepG2 cells,the effectiveness of the photothermal therapy/photodynamic therapy/chemodynamic therapy/chemotherapy combination therapy mediated by the nanoparticles was detected by employing fluorescence imaging and MTT assay. RESULTS AND CONCLUSION:(1)The h-PCuNF nanoparticles possessed a hollow spherical structure in which the CuNPs(drug loading rate and encapsulation rate were 26.3%and 63.2%,respectively)and NF(drug loading rate and encapsulation rate were 11.0%and 52.6%,respectively)were loaded into the shell.The average particle size of the h-PCuNF nanoparticles was(309.2±10.0)nm,while the zeta potential was determined to be(-12.5±0.9)mV.In physiological environments,the nanoparticles possess favorable suspension stability.(2)In deionized water,the h-PCuNF nanoparticles could markedly enhance T1-weighted magnetic resonance imaging images.The h-PCuNF nanoparticles showed remarkable photothermal conversion and photocatalytic reactive oxygen species generation capabilities under near infrared laser irradiation.In addition,the h-PCuNF nanoparticles could consume glutathione and mediate Fenton-like reactions to produce·OH.(3)The h-PCuNF nanoparticles could be taken up by HepG2 tumor cells and were mainly distributed in the cytoplasm.The synergistic therapeutic effect was demonstrated after the nanoparticles were activated by near infrared laser irradiation,because CuNPs mediated photothermal therapy/photodynamic therapy/chemodynamic therapy and NF mediated chemotherapy could synergistically eliminate the tumor cells.

BACKGROUND:The regulation of M1/M2 polarization direction of macrophages is particularly critical in tissue engineering applications,and timely regulation can minimize proinflammatory,anti-inflammatory,or tissue healing responses. OBJECTIVE:To implant lentivirus-mediated miRNA-378a macrophage strain complex collagen to detect the expression level of immune regulation in the in vivo environment,and further clarify the influence of miRNA-378a in promoting macrophage M2 polarization in immune regulation and tissue repair in the in vivo environment. METHODS:Lentivirus-mediated miRNA-378a overexpressing macrophage cell lines and negative control virus macrophage lines were amplified and screened,and the macrophage lines were recovered and cultured together with collagen sponge to form a composite scaffold,which was divided into the following groups:(1)Positive group:miRNA-378a overexpressing macrophage-collagen sponge composite;(2)negative group:negative control of virus-mediated miRNA-378a macrophage-collagen sponge composite;(3)control group:macrophage-collagen sponge;(4)blank control group:collagen sponge.The cell density,phenotype,and adhesion of each group were observed by immunofluorescence and scanning electron microscopy.The cells were implanted into the subcutaneous model of the back of mice,and the mice were sacrificed 4 and 7 days after modeling.The direction of macrophage polarization in the collagen sponge composite of macrophages with miRNA-378a overexpression mediated by lentivirus and its effect on immune regulation and tissue repair were analyzed by gross observation,hematoxylin-eosin staining,MASSON staining,and immunohistochemistry. RESULTS AND CONCLUSION:(1)Under immunofluorescence microscopy,the macrophage cell lines in each group were observed to form a composite scaffold with the collagen sponge.(2)Under scanning electron microscope,lentivirus-mediated miRNA-378a macrophages in the positive group proliferated in cell density,had spherical,elliptic and polygonal differentiation,and had more pseudofeet than other groups.(3)Under general observation,the overall 7-day healing was better than that at 4 days.Lentivirus-mediated miRNA-378a macrophages in the positive group healed better than other groups regardless of 4 and 7 days.(4)Lentivirus-mediated miRNA-378a macrophages in the positive group under hematoxylin-eosin staining and MASSON staining had more amounts of fibrocytes,capillaries,fibroblasts,and collagen fiber hyperplasia.(5)Immunohistochemistry showed that lentivirus-mediated miRNA-378a macrophages in the positive group were more positive in 4-and 7-day M2 polarized cells than in other groups.The macrophages of the control and negative groups in 4-and 7-day M2 polarized cells were greater than that of the blank control group.There was no statistical difference between the control group and the negative group.The number of stained cells in the positive,negative,and control groups regardless of 4 and 7 days was higher than that in the blank control group,and the positive group>negative group ≈ control group>blank control group.(6)It is concluded that macrophages with miRNA-378a overexpression have a large amount of fibroblasts,capillaries,fibroblasts,and collagen fiber hyperplasia in vivo,which has a positive effect on tissue repair,and can promote the polarization of macrophages towards M2 type and inhibit the polarization of M1 type,thus contributing to reducing the inflammatory response of the body.

BACKGROUND:According to existing clinical studies,vertebroplasty treatment with both the external pedicle approach and the pedicle approach can improve the pain and quality of life of patients with spinal compression fractures.Compared with the pedicle approach,the external pedicle approach has a freer puncture angle,and good bone cement dispersion effect can be obtained by adjusting the puncture angle. OBJECTIVE:To compare the impact of vertebroplasty through individualized unilateral external pedicle approach and bilateral pedicle approach on the treatment of spinal compression fractures by quantifying the dispersion effect of bone cement. METHODS:A total of 80 patients with thoracolumbar compression fracture were divided into two groups by random number table method.The bilateral pedicle group(n=40)underwent vertebroplasty through a bilateral pedicle approach,while the unilateral external pedicle group(n=40)underwent individualized vertebroplasty through a unilateral external pedicle approach.Anteroposterior and lateral X-rays of the affected vertebrae from two groups of patients were photographed to assess effect and type of bone cement dispersion within 3 days after surgery.Visual analog scale score,tenderness threshold around fracture,and Oswestry dysfunction index were assessed before,1,7 days,and 1 month after surgery. RESULTS AND CONCLUSION:(1)Dispersion effect of bone cement in unilateral external pedicle group was better than that in bilateral pedicle group(P<0.001),and the amount of bone cement perfusion was higher than that in bilateral pedicle group(P<0.001).In the bilateral pedicle group,the bone cement dispersion types were mainly concentrated in type Ⅰ and type Ⅲ,while in the unilateral external pedicle group,the bone cement dispersion types were mainly concentrated in type I and type Ⅱ,and there was a significant difference in bone cement dispersion types between the two groups(P<0.001).(2)Postoperative visual analog scale scores and Oswestry disability index of both groups were lower than those before surgery(P<0.001),and postoperative tenderness threshold around fracture showed a trend of decreasing first and then increasing.At the same time point after treatment,there were no significant differences in visual analog scale score,Oswestry disability index,and tenderness threshold around fracture between the two groups(P>0.05).(3)The results indicate that individualized vertebroplasty via unilateral external pedicle approach can achieve better bone cement dispersion,and the treatment effect is consistent with the vertebroplasty via classical bilateral pedicle approach.

BACKGROUND:Platelet-rich fibrin(PRF)has many advantages,such as simple preparation,low production cost,and high safety,and has been widely used in the study of bone defect repair in oral and maxillofacial surgery,but there are problems such as too fast degradation rate and short release time of growth factors. OBJECTIVE:PRF was loaded into gelatin methacryloyl(GelMA)hydrogel and its osteogenic properties were analyzed by in vivo and in vitro experiments. METHODS:(1)New Zealand white rabbit venous blood was extracted to prepare PRF.GelMA hydrogels containing 0,0.05,0.075,and 0.1 g PRF were prepared,respectively,and were recorded as GelMA,GelMA/PRF-0.05,GelMA/PRF-0.075,and GelMA/PRF-0.1,respectively,to characterize the micromorphology and in vitro slow-release properties of the hydrogels.(2)Four kinds of hydrogels were co-cultured with MC3T3-E1 cells,respectively,and the cell proliferation activity was detected with the single cultured cells as the control.After osteogenic induction,alkaline phosphatase activity,mineralization ability,mRNA and protein expression levels of osteogenic genes(osteocalcin,osteopontin,RUNX2),ERK1/2-p38 MAPK pathway protein mRNA and protein expression levels were detected.(3)Fifteen New Zealand white rabbits were taken.Four full-layer bone defects of 8 mm diameter were prepared in the skull of each rabbit,one of which was implanted without any material(blank control group),and the other three were implanted with GelMA hydrogel,PRF,and GelMA/PRF-0.1 hydrogel,respectively.The bone defect was detected by Micro-CT and bone morphology was observed at 4,8,and 12 weeks after operation. RESULTS AND CONCLUSION:(1)Scanning electron microscopy observed that all the hydrogels of the four groups had honeycomb pore structure,and the pore size of the hydrogels decreased slightly with the increase of PRF content,but there was no significant difference between the groups.The three groups of GelMA/PRF hydrogel could release transforming growth factor β1 and insulin-like growth factor 1 at a certain rate,and the cumulative release of transforming growth factor β1 and insulin-like growth factor 1 increased significantly with the extension of time.(2)CCK-8 assay and live/dead staining showed that GelMA/PRF hydrogel could promote the proliferation of MC3T3-E1 cells.The results of alkaline phosphatase staining,alizarin red staining,and osteogenic gene detection showed that GelMA/PRF hydrogel could promote the osteogenic differentiation of MC3T3-E1 cells,and inhibit the expression of ERK1/2-p38 MAPK pathway protein,and showed a PRF content dependence.(3)Micro-CT scan showed that the bone mineral density and bone volume fraction in the bone defect of GelMA/PRF-0.1 hydrogel group were higher than those in the other three groups(P<0.05).Hematoxylin-eosin staining showed that compared with the other three groups,GelMA/PRF-0.1 hydrogel group had faster and more mature new bone formation at the bone defect.(4)These findings indicate that GelMA/PRF hydrogel has good osteogenic activity both in vivo and in vitro,which may be related to inhibiting the expression of ERK1/2-p38 MAPK pathway protein.

BACKGROUND:The healing of mandibular fractures after rigid internal fixation is influenced by many factors,including the material of the bone plate,fracture site,and bone density of the patient.However,there are relatively few studies on the relationship between the stability of mandibular fracture fixation in different bone qualities and they lack a scientific basis. OBJECTIVE:To analyze the stability of fixation of mandibular fractures with different bone qualities with bioabsorbable plates and miniature titanium plates by finite element analysis. METHODS:Three-dimensional finite element models of class Ⅰ-Ⅳ mandibular fractures were developed according to the bone quality classification method proposed by ZARB and LEKHOLM.The fractures at the median mandibular symphysis,mandibular body,and mandibular angle were simulated under different bone qualities.Bioabsorbable bone grafting plates(or miniature titanium plates)were placed at each fracture site for fixation and to simulate the state of healthy side occlusion.Finite element analysis on the model was used to analyze the relative displacement of the fracture segments and the stress distribution of fixators. RESULTS AND CONCLUSION:(1)The maximum stress value during fixation with titanium plates increased gradually with the increase of bone class,in which the maximum stress value of titanium plates was the highest in the mandibular body class Ⅳ bone group,which was 382.74 MPa and 96.11 MPa in the miniature titanium plate and bioabsorbable plate groups.The results for mandibles of the same bone type showed that the maximum stress value of titanium plates was much higher than that of bioabsorbable plates.(2)For fractures of the median middle of the mandible in types Ⅲ and Ⅳ,the displacement of the fracture breaks at the fixation site was large and exceeded the limiting value of bone healing(>150 μm),regardless of whether the fixation was performed with a miniature titanium plate or a bioabsorbable plate.For type Ⅳ mandibular fractures,the fracture end displacement in the bioabsorbable plate group exceeded the healing limit value,and the fracture end displacement in the miniature titanium plate group was close to the healing limit value.Under the same bone quality and fracture site,the fracture displacement of the miniature titanium plate group was smaller than that of the bioabsorbable plate group.(3)The results showed that the strength and stiffness of the two internal fixations were sufficient to support bone healing of fractures at three sites of the types Ⅰ-Ⅳ mandible,and the fixation stability of the bioabsorbable plate was almost the same as that of the miniature titanium plate,which could provide early healing conditions for fractures.Mandibular bone type should be taken into consideration in the treatment of mandibular fracture.The higher the mandibular bone grade,the worse the stability of fracture fixation,and the more likely the complications such as poor bone healing will occur after surgery.

BACKGROUND:Magnetic nanomaterials have biological activities such as promoting osteogenic differentiation of stem cells and inhibiting osteoclast formation,and can effectively promote the healing of injured bone tissue under the synergistic effect of magnetic fields.They have a very broad application prospect in bone injury repair. OBJECTIVE:To review the mechanism of magnetic nanomaterials and magnetic fields promoting bone repair,as well as their research progress in the field of bone injury repair. METHODS:Relevant literature search was conducted in PubMed and Web of Science databases with the search terms"magnetic nanomaterials,magnetic field,bone repair,bone tissue engineering,stem cell,osteoblast,osteoclast."The time limit of literature search was from 2003 to 2023,which was screened and analyzed.Some classic articles were manually retrieved,and 98 articles were finally included for analysis. RESULTS AND CONCLUSION:(1)Magnetic nanomaterials have biological effects such as promoting osteoblast differentiation,inhibiting osteoclast formation and regulating the immune microenvironment.In addition,magnetic nanomaterials can regulate the physicochemical properties of tissue engineering scaffolds,such as mechanical properties and surface morphology,and endowed with magnetic properties,which is conducive to the regulation of the adhesion,proliferation and osteogenic differentiation of stem cells.(2)The magnetic field has the ability to regulate multiple cell signaling pathways to promote osteoblast differentiation,inhibit osteoclast formation,stimulate angiogenesis and other biological effects,thus accelerating the healing of damaged bone tissue.(3)The joint application of magnetic nanomaterials and magnetic field accelerates the repair of bone damage by activating mechanotransduction,increasing the content of intracellular magnetic nanoparticles,and enhancing the effect of micro-magnetic field,which provides a new idea for the research of bone tissue engineering.(4)Magnetic field has demonstrated definite efficacy in the treatment of clinical fractures,osteoporosis,and osteoarthritis diseases,which is beneficial for bone tissue growth,reducing bone loss,alleviating pain,and improving the quality of life of patients.(5)Magnetic nanomaterials and magnetic fields have great potential for application in bone damage repair and regeneration,but the interaction mechanism between magnetic nanomaterials,magnetic fields,and cells has not been fully elucidated.Moreover,the key parameters of magnetic fields that regulate intracellular molecular events,including the type,intensity,frequency,duration,and mode of the magnetic field,as well as the precise biological effects of a specific magnetic field on osteoblasts and the underlying mechanisms,have yet to be defined.(6)Further attention needs to be paid to the effects on osteoclasts,nerves,blood vessels,and immune cells in the microenvironment of damaged tissues.Finally,the safety of magnetic materials for human use is yet to be systematically studied in terms of their distribution,metabolism,and acute and chronic toxicities.

BACKGROUND:Zinc-based alloy medical implant materials have excellent mechanical properties,complete degradability and good biocompatibility,and are mainly used in orthopedic implants,cardiovascular stents,bile duct stents,tracheal stents,nerve catheters,etc. OBJECTIVE:To review the research progress of biodegradable zinc-based alloys in bone defect repair and prospect the promising research direction and achievements of zinc-based materials. METHODS:After searching PubMed,Web of Science,WanFang Data,and CNKI databases from the establishment of the database to June 2023,various relevant articles on biodegradable zinc-based alloys for bone implant material research were collected.The basic characteristics of biodegradable zinc based alloys were summarized,and the role of zinc-based alloys in promoting bone tissue repair was sorted and summarized.The current research hotspots and shortcomings were discussed. RESULTS AND CONCLUSION:(1)Zinc-based alloys have good biocompatibility.Using zinc-based alloys as the matrix material,with the help of scaffold structure construction technology and coating optimization process,the bone conductivity of zinc-based alloys will be effectively improved,and their degradation products will have efficient bone induction to regulate the gene expression of osteoblasts and osteoclasts,thereby promoting the repair and reconstruction of bone defects.(2)However,in the research on optimizing zinc-based alloys,the coating process is relatively insufficient,and additive loading technology is still lacking.(3)Zinc-based alloys have excellent mechanical and biological properties.Through special processes,their bone conductivity and osteoinductivity can be increased to effectively improve their ability to promote bone repair and reconstruction,and it is expected to further achieve the development of personalized transplant materials.Further research and development are needed to optimize the integration of coating and additive loading technologies into zinc-based alloys.

BACKGROUND:Gradient artificial bone repair scaffolds can mimic unique anatomical features in musculoskeletal tissues,showing great potential for repairing injured musculoskeletal tissues. OBJECTIVE:To review the latest research advances in gradient artificial bone repair scaffolds for tissue engineering in the musculoskeletal system and describe their advantages and fabrication strategies. METHODS:The first author of the article searched the Web of Science and PubMed databases for articles published from 2000 to 2023 with search terms"gradient,bone regeneration,scaffold".Finally,76 papers were analyzed and summarized after the screening. RESULTS AND CONCLUSION:(1)As an important means of efficient and high-quality repair of skeletal system tissues,gradient artificial bone repair scaffolds are currently designed bionically for the natural gradient characteristics of bone tissue,bone-cartilage,and tendon-bone tissue.These scaffolds can mimic the extracellular matrix of native tissues to a certain extent in terms of structure and composition,thus promoting cell adhesion,migration,proliferation,differentiation,and regenerative recovery of damaged tissues to their native state.(2)Advanced manufacturing technology provides more possibilities for gradient artificial bone repair scaffold preparation:Gradient electrospun fiber scaffolds constructed by spatially differentiated fiber arrangement and loading of biologically active substances have been developed;gradient 3D printed scaffolds fabricated by layered stacking,graded porosity,and bio-3D printing technology;gradient hydrogel scaffolds fabricated by in-situ layered injections,simple layer-by-layer stacking,and freeze-drying method;and in addition,there are also scaffolds made by other modalities or multi-method coupling.These scaffolds have demonstrated good biocompatibility in vitro experiments,were able to accelerate tissue regeneration in small animal tests,and were observed to have significantly improved histological structure.(3)The currently developed gradient artificial bone repair scaffolds have problems such as mismatch of gradient scales,unclear material-tissue interactions,and side effects caused by degradation products,which need to be further optimized by combining the strengths of related disciplines and clinical needs in the future.