BACKGROUND:Multistimuli-responsive hydrogels have received extensive attention in the field of bone tissue engineering due to their special responsive capabilities and diverse functions.OBJECTIVE:To review the application of multistimuli-responsive hydrogels in bone damage repair,and explore their research and development ideas and future development directions.METHODS:Relevant literature was retrieved from PubMed,Web of Science,and WanFang databases.English search terms included"hydrogels,bone defect,bone repair,bone healing,bone tissue engineering,degenerative joint diseases,osteoarthritis,Cartilage."Chinese search terms were"multistimuli-responsive hydrogels,smart hydrogels,bone damage repair,bone tissue engineering."The search time limit was from database inception to August 2024.A total of 83 articles were included in the review.RESULTS AND CONCLUSION:Multistimuli-responsive hydrogels can react to various levels of physical,chemical,and biological stimuli,while exerting inherent functions such as swelling,deformation,degradation,and other special functions endowed by materials,making them highly potential in addressing clinical problems in bone damage repair.However,in practical applications,how to ensure that these materials maintain stability and durability in the complex biological environment and can be degraded in a controllable and harmless manner when needed is an urgent problem to be solved.

BACKGROUND:Cell-free therapy is a research hotspot in the field of medical cosmetic anti-aging.It is still unknown for paracellular secretion of human umbilical cord mesenchymal stem cell-derived small extracellular vesicles loaded with the antiaging drug α-ketoglutaric acid to delay skin aging.OBJECTIVE:To investigate the effect of the anti-aging agent α-ketoglutarate engineered human umbilical cord mesenchymal stem cell-derived small extracellular vesicles in a D-galactose-induced model of dermal fibroblast senescence.METHODS:(1)Biological characteristics of primary human umbilical cord mesenchymal stem cells were identified by osteogenic-lipogenic differentiation staining and flow cytometry.(2)The small extracellular vesicles derived from human umbilical cord mesenchymal stem cell were obtained by using differential-ultracentrifugation.α-Ketoglutarate-engineered human umbilical cord mesenchymal stem cell-small extracellular vesicles were constructed by electroporation,and biologically characterized by transmission electron microscopy and nanoparticle tracking analyzer,while the encapsulation rate was assessed using high-performance liquid chromatography.(3)The effect of α-ketoglutarate on the proliferative capacity of dermal fibroblasts was assessed by CCK-8 and Edu cell proliferation assay kits.(4)The effect of α-ketoglutarate-engineered human umbilical cord mesenchymal stem cell-small extracellular vesicles on delaying the senescence of dermal fibroblasts was evaluated by reactive oxygen species detection kit,western blot assay,and cellular immunofluorescence.RESULTS AND CONCLUSION:(1)The obtained human umbilical cord mesenchymal stem cell and human umbilical cord mesenchymal stem cell-small extracellular vesicles were biologically compatible.(2)There was no toxic effect on dermal fibroblasts when α-ketoglutarate was used in the concentration range of 0.5-8 mmol/L.(3)D-gal induced senescence in dermal fibroblasts,while α-ketoglutarate-engineered human umbilical cord mesenchymal stem cell-small extracellular vesicles treatment reduced the level of oxidative stress,DNA damage,and collagen loss,which was further verified that α-ketoglutarate-engineered human umbilical cord mesenchymal stem cell-small extracellular vesicles could effectively slow down the skin aging process.

BACKGROUND:The local immune microenvironment plays an important regulatory role in the process of bone formation,and the immune system is intricately linked to the skeletal system.OBJECTIVE:To systematically review the promotion of bone regeneration from three aspects:immune cell regulation of microenvironment,regulation of immune response by small extracellular vesicles,and induction of immune response by bone biomaterials,and to elucidate the immune regulatory mechanisms involved in bone regeneration.METHODS:Relevant literature was retrieved from PubMed,CNKI,WanFang Database,and VIP Database,using the search terms of"osteoimmunology,immune microenvironment,small extracellular vesicles,bone regeneration,bone tissue repair,biomaterials,and tissue engineering"in English and Chinese.Repeat and irrelevant literature was screened and removed,and 92 articles that met the criteria were selected for intensive reading and review.RESULTS AND CONCLUSION:Multiple immune cells and bone cells are in the same microenvironment,and immune cells can regulate the differentiation and activity of bone cells,collectively forming an immune microenvironment that affects bone regeneration.Neutrophils can significantly reduce local inflammatory responses in the early stages of bone injury,creating a favorable microenvironment for bone regeneration.M1 macrophages can clear foreign bodies and reduce early inflammatory responses,while M2 macrophages can promote the expression of osteogenic markers and factors,playing an important role in the repair process of bone injury.B cells and T cells can directly or indirectly affect the generation and activity of osteoblasts and osteoclasts,regulate bone metabolism,and promote bone regeneration.Extracellular vesicles of small cells regulate the local immune microenvironment through paracrine secretion,promoting bone formation and angiogenesis at the site of bone injury.The metal ions,surface hydrophilicity,porosity,pore size,surface morphology,and surface roughness on the surface of biomaterials can directly regulate local immune responses,and have anti-inflammatory,angiogenic,and osteogenic effects,thereby accelerating bone regeneration.

With the continuous development of new surgical technology, new equipment and new concepts, the research focused in the field of surgery is also in constant change. Among them, there are still confusion and controversies in the current clinical practice when facing the one-stop proposition of benefit population screening, advantageous surgical indication decision-making, surgical intervention timing selection, postoperative complication prediction and management. Therefore, our team tries to analyze whether the concept of"co-management of liver and pancreas"exists in clinical practice from the aspects of anatomy, physiology, histology and embryology of liver and pancreas, as well as the interaction between liver and pancreas, and explore the relationship between liver and pancreas in anatomy and tissue embryonic development, and the relationship between the concept of"co-management of liver and pancreas"and pancreatitis and pancreatic tumors as well as the concept of “co-management of liver and pancreas” applied in neoadjuvant chemoradiotherapy, and attempts to establish a new treatment pathway for pancreatic diseases based on this concept, in order to provide a new idea, new scheme and new possibility for the clinical research of pancreatic diseases and pancreatic surgery.

ObjectiveThis study aims to explore the effect of Feiyanning granules on ferroptosis in lung cancer cells and its regulatory function within the nuclear transcription factor E₂-related factor 2 （Nrf2）/mouse solute carrier family 7 member 11 （SLC7A11）/glutathione peroxidase 4 （GPX4） signaling pathway. MethodsThe cell counting kit-8 （CCK-8） method was used to detect the effect of Feiyanning granule on the proliferation of A549 lung cancer cells. A549 lung cancer cells were categorized into a blank group， a ferroptosis inhibitor-1 （Fer-1） group （10 μmol·L^-1）， a Feiyanning granules （600 mg·L^-1） group， and a Feiyanning granules + Fer-1 group. After 48 hours of intervention， the activity and morphology of the cells were observed. The CCK-8 method was employed to measure cell viability. Biochemical assays were carried out to measure the levels of reactive oxygen species （ROS）， malondialdehyde （MDA）， glutathione （GSH）， and ferrous ions （Fe²⁺） in A549 cells. Western blot was utilized to evaluate the expression levels of Kelch-like ECH-associated protein 1 （Keap1）， Nrf2， SLC7A11， and GPX4 proteins. A549 lung cancer cells were categorized into a blank group and a Feiyanning Granule group （600 mg·L^-1）， and mitochondrial morphology was examined via transmission electron microscopy （TEM）. ResultsAfter the intervention of Feiyaning granules， the proliferation of A549 cells was significantly inhibited in a concentration-dependent manner compared with that in the blank group （P<0.01）. Compared with the blank group， the Feiyanning granules group exerted an significantly inhibitory effect on the viability of lung cancer cells （P<0.01）. Compared with that in the Feiyanning granules group， the cell viability in the Feiyanning granules +Fer-1 group was obviously restored （P<0.05）. Compared with the blank group， the Feiyanning Granule group showed a significant increase in the levels of ROS， MDA， and Fe²⁺ （P<0.01）， a significant decrease in the GSH level （P<0.01）， and facilitated ferroptosis. Compared with the blank group， the Feiyanning granules group showed significantly decreased expression of Nrf2， SLC7A11， and GPX4 proteins and enhanced expression of Keap1 （P<0.01）. Compared with those in the Feiyanning Granule group， the protein levels of Nrf2， SLC7A11， and GPX4 increased significantly （P<0.01）， and the expression of Keap1 decreased significantly in the Feiyanning granules + Fer-1 group （P<0.01）. Compared with the blank group， the Feiyaning granules group exhibited reduced mitochondrial size and increased matrix electron density. ConclusionFeiyanning granules can induce ferroptosis in lung cancer cells， and its underlying mechanism might be associated with the inhibition of the Nrf2/SLC7A11/GPX4 signaling pathway.

ObjectiveThis study aims to investigate the action mechanism by which Xiaozheng Zhitong paste （XZP） alleviates bone cancer pain （BCP） by regulating programmed death protein 1 （PD-1）/programmed death-ligand 1 （PD-L1） pathway-induced osteoclast formation. MethodsThirty female C57BL/6 mice were randomly allocated into the following groups （n=6 per group）： normal control group， model group， low‑dose XZP group （31.5 g·kg^-1）， high‑dose XZP group （63 g·kg^-1）， and PD‑1 inhibitor （Niv） group. A bone cancer pain （BCP） model was established by injecting Lewis lung carcinoma cells. Mice in the normal control and model groups received topical application of a blank paste matrix at the wound site. Mice in the low‑ and high‑dose XZP groups were treated with XZP applied topically twice daily. Mice in the Niv group were topically administered the blank paste matrix and additionally received Niv via tail‑vein injection every two days. All interventions were continued for 21 days. During this period， behavioral tests were performed to assess mechanical， motor， and thermal nociceptive sensitivities. After 21 days， all mice were euthanized， and bone tissue from the operated side was collected for sectioning and preservation. Tartrate‑resistant acid phosphatase （TRAP） staining was used to evaluate osteoclast expression in the lesioned bone tissue. Immunohistochemistry was performed to detect the expression of Runt‑related transcription factor 2 （Runx2） in the lesioned bone tissue. Immunofluorescence was employed to assess the expression of PD‑1 and PD‑L1 in the lesioned bone tissue. ResultsCompared with the normal group， the model group showed significantly decreased limb mechanical withdrawal threshold， spontaneous paw flinching， and thermal withdrawal latency （P<0.01）， increased number of osteoclasts in the lesioned bone tissue （P<0.01）， and reduced expression of Runx2 （P<0.01）. Compared with the model group， the BCP mice in the XZP low-dose group， XZP high-dose group， and Niv group exhibited increased limb mechanical withdrawal threshold， movement scores， and thermal withdrawal latency （P<0.01）. The XZP low-dose group showed no significant changes in osteoclast number or Runx2 expression， while the XZP high-dose group and Niv group demonstrated significantly reduced osteoclast numbers （P<0.01） and significantly increased Runx2 expression （P<0.01）. In the lesioned bone tissue of BCP mice， the XZP low-dose group showed no significant decrease in the percentage of PD-1 expression， but a decrease in the percentage of PD-L1 expression （P<0.05）. In contrast， both the XZP high-dose group and the Niv group exhibited significant reductions in the percentages of PD-1 and PD-L1 expression （P<0.01）. ConclusionXZP alleviates the pain of mice with BCP by blocking the PD-1/PD-L1 pathway to inhibit osteoclastogenesis.

ObjectiveThe paper aims to investigate the mechanism by which Xiaozheng Zhitong paste （XZP） alleviates bone cancer pain （BCP） through regulating the PTEN-induced putative kinase 1 （PINK1）/Parkin-mediated mitophagy-NOD-like receptor protein 3 （NLRP3） inflammasome pathway to suppress microglial pyroptosis. MethodsLipopolysaccharide （LPS） and LPS-adenosine triphosphate （ATP） were used to establish an inflammation and pyroptosis model in microglial cells. The cells were randomly divided into the following groups： control group， LPS group， LPS+low-dose XZP group， LPS+high-dose XZP group， LPS-ATP group， LPS-ATP+low-dose XZP group， LPS-ATP+high-dose XZP group， LPS-ATP+XZP group， and LPS-ATP+XZP+CsA group. Techniques including terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL） staining， enzyme-linked immunosorbent assay （ELISA）， Western blot， and confocal fluorescence staining were employed to assess the effects of XZP on microglial apoptosis， inflammatory cytokine release， inflammasome activation， pyroptosis， and mitophagy. ResultsIn vitro experiments showed that compared with the blank group， the LPS group exhibited significantly increased levels of microglial apoptosis and pro-inflammatory factors interleukin （IL）-1β， IL-6， and tumor necrosis factor-α （TNF-α）（P<0.01）， along with significantly upregulated protein expression of inducible nitric oxide synthase （iNOS）， cyclooxygenase-2 （COX-2）， and phosphorylated nuclear factor-κB p65 （p-NF-κB p65） （P<0.01）. Compared with the LPS group， the high-dose LPS-XZP group significantly reduced the level of apoptosis （P<0.01） and the content of the aforementioned pro-inflammatory factors （P<0.01）. Both the low- and high-dose LPS-XZP groups dose-dependently downregulated the protein expression of iNOS， COX-2， and p-NF-κB p65 （P<0.05， P<0.01）. Compared with the blank group， the LPS-ATP group showed significantly upregulated expression of pyroptosis-related proteins， including Caspase-1/pro-Caspase-1， N-terminal fragment of gasdermin D （GSDMD-N）/full-length gasdermin D （GSDMD-F）， NLRP3， apoptosis-associated speck-like protein containing a CARD （ASC）， IL-1β precursor （pro-IL-1β）， and mature IL-1β （P<0.01）. The levels of pyroptotic factors IL-1β and IL-18 were significantly elevated （P<0.01）， and membrane pore formation and intracellular reactive oxygen species （ROS） levels were significantly increased （P<0.01）. Compared with the LPS-ATP group， both the low- and high-dose LPS-ATP+XZP groups dose-dependently downregulated the expression of the aforementioned pyroptosis-related proteins （P<0.05， P<0.01）. The low-dose LPS-ATP+XZP group reduced IL-1β levels （P<0.01）， while the high-dose group reduced both IL-1β and IL-18 levels （P<0.01） Both the low- and high-dose LPS-ATP+XZP groups dose-dependently reduced membrane pore formation and intracellular ROS production （P<0.01）. Compared with the blank group， the LPS-ATP group showed significantly reduced expression of mitophagy-related proteins PINK1 and Parkin， and a decreased ratio of microtubule-associated protein 1 light chain 3Ⅱ（LC3Ⅱ） to LC3Ⅰ（P<0.01）， while p62 expression was significantly increased （P<0.01）. Mitochondrial ROS levels were significantly enhanced （P<0.01）. Compared with the LPS-ATP group， both the low- and high-dose LPS-ATP+XZP groups dose-dependently reversed the expression of these proteins （P<0.05， P<0.01） and reduced mitochondrial ROS levels （P<0.01）. After treatment with the mitophagy inhibitor cyclosporin A （CsA）， the beneficial effects of XZP on mitochondrial function and its inhibitory effects on pyroptosis-related protein expression were significantly reversed （P<0.05， P<0.01）. ConclusionXZP reduces ROS levels by activating PINK1/Parkin-mediated mitophagy， thereby inhibiting NLRP3 inflammasome activation and microglial pyroptosis， which provides new molecular evidence for the mechanism by which XZP alleviates BCP.

ObjectiveTo investigate the effects and underlying mechanisms of Xiaozheng Zhitong Paste （XZP） on bone cancer pain （BCP）. MethodsThirty female BALB/c mice were randomly divided into five groups： a Sham group， a BCP group， a BCP+low-dose XZP group， a BCP+high-dose XZP group， and a BCP+high-dose XZP + protease-activated receptor 2 （PAR2） agonist GB-110 group. BCP mice model was constructed by injecting Lewis lung carcinoma cells into the femoral cavity of the right leg， which was followed by being treated with XZP for 21 d. After 21 d， the mice were sacrificed. Nissl staining was used to evaluate the survival of spinal cord neurons. Immunofluorescence staining was conducted to localize ionized calcium-binding adapter molecule 1 （Iba1） and neuronal nuclear antigen （NeuN） in spinal cord tissue， thereby assessing microglial activation and neuronal survival. Enzyme-linked immunosorbent assay （ELISA） was employed to measure the levels of interleukin-1β （IL-1β）， tumor necrosis factor-α （TNF-α）， interleukin-6 （IL-6）， transforming growth factor-β （TGF-β）， interleukin-4 （IL-4）， and interleukin-10 （IL-10） in spinal cord tissue. Real-time quantitative polymerase chain reaction （Real-time PCR） was used to detect mRNA expression levels associated with M1/M2 polarization of microglia. Western blot analysis was performed to examine the expression of proteins related to microglial polarization as well as those involved in the PAR2/nuclear factor kappa B （NF-κB）/NOD-like receptor protein 3 （NLRP3） signaling pathway in the spinal cord. ResultsCompared with the Sham group， the spinal cord neurons were damaged， the number of Nissl-positive spinal cord neurons in the spinal cord tissue was significantly reduced （P<0.01）， and the rate of NeuN-positive cells was significantly decreased （P<0.01）. The spinal cord microglia were activated， the inflammatory level of the spinal cord tissue was enhanced， and Iba1 staining was significantly enhanced （P<0.01）. The levels of IL-1β， TNF-α， IL-6， TGF-β， IL-4 and IL-10 were significantly increased （P<0.01）. The mRNA expressions of IL-1β， TNF-α and inducible nitric oxide synthase （iNOS） were significantly increased （P<0.01）， and the expression of PAR2， NLRP3， ASC and NF-κB p65 proteins in the spinal cord tissue of the BCP mice was significantly enhanced （P<0.01）. Compared with the BCP group， high-dose XZP treatment significantly increased the number of Nissl-positive spinal cord neurons in the BCP mice （P<0.01）， significantly enhanced the rate of NeuN-positive cells in the spinal cord tissue， and significantly weakened Iba1 staining （P<0.01）. In addition， the levels of IL-1β， TNF-α， and IL-6 were significantly decreased， while the levels of TGF-β， IL-4， and IL-10 were significantly increased （P<0.05， P<0.01）. The mRNA expression levels of IL-1β， TNF-α， and iNOS were decreased， whereas those of cluster of differentiation 206 （CD206）， arginase-1 （Arg-1）， and YM1/2 were significantly increased （P<0.05， P<0.01）. Low-dose and high-dose XZP treatment significantly decreased the expression of PAR2， NLRP3， ASC， and NF-κB p65 proteins in the spinal cord tissue （P<0.05， P<0.01）. These effects could all be significantly eliminated by the PAR2 agonist GB-110. ConclusionXZP can mitigate BCP in mice， which may be achieved through blocking the activated PAR2/NF-κB/NLRP3 pathway.

ObjectiveThe paper aims to investigate the action mechanism by which the Xiaozheng Zhitong paste （XZP） relieves bone cancer pain （BCP）. MethodsA model of mice with BCP was established by using Lewis tumor cells. The therapeutic effects of XZP， the ferroptosis inhibitor Ferrostatin-1 （Fer-1）， and the nuclear factor erythroid 2-related factor 2 （Nrf2） inhibitor Brusatol （Bru） on BCP were examined. Mice were randomly divided into the Sham operation group， BCP group， BCP+XZP-L group， BCP+XZP-H group， BCP+Fer-1 group， and BCP+XZP-H+Bru group， with six mice in each group. Pain behavior tests were conducted on the mice to assess pain levels. Colorimetric assays were employed to measure ferroptosis-related factors in serum and spinal cord tissue including Fe， malondialdehyde （MDA）， reactive oxygen species （ROS）， and superoxide dismutase （SOD）. Immunofluorescence staining was used to assess ROS production in spinal cord tissue. Transmission electron microscopy was used to observe the ultrastructure of mitochondria in lumbar spinal cord tissue. Quantitative real-time polymerase chain reaction （Real-time PCR） was employed to detect mRNA expression of Nrf2， heme oxygenase-1 （HO-1）， glutathione peroxidase 4 （GPX4）， and solute carrier family 7 member 11 （SLC7A11） in spinal cord neuron tissue. The protein expression of Nrf2， HO-1， GPX4， and SLC7A11 in spinal cord neurons was measured by Western blot. ResultsCompared with the Sham group， mice in the BCP group exhibited significantly reduced limb usage scores， mechanical foot withdrawal thresholds， and thermal foot withdrawal thresholds （P<0.01）. Serum and lumbar spinal cord tissue levels of Fe， MDA， and reactive oxygen species （ROS） were significantly elevated （P<0.05）， while superoxide dismutase （SOD） levels were significantly decreased （P<0.05）. Lumbar spinal cord mitochondrial structural damage was observed， and mRNA and protein expression of Nrf2， HO-1， GPX4， and SLC7A11 were significantly downregulated （P<0.01）. Compared with the BCP group， both low- and high-dose XZP groups improved the aforementioned pain behavioral indicators （P<0.05，P<0.01）， reduced ferroptosis-related biomarkers including Fe， MDA， and ROS levels （P<0.05）， increased SOD levels （P<0.05，P<0.01）， alleviated mitochondrial damage， and upregulated Nrf2， HO-1， GPX4， SLC7A11 mRNA and protein expression （P<0.05，P<0.01）. The high-dose XZP group exhibited comparable efficacy to Fer-1 in alleviating pain and inhibiting ferroptosis. Following Bru administration， XZP's effects on pain behavioral indicators， regulation of ferroptosis-related markers， mitochondrial structural protection， and activation of the Nrf2/HO-1/GPX4/SLC7A11 pathway were significantly reversed （P<0.05，P<0.01）. ConclusionExternal application of XZP alleviates pain symptoms in BCP mice by activating the Nrf2/HO-1/GPX4/SLC7A11 pathway， thereby inhibiting ferroptosis and neuronal damage in spinal cord neurons.

Cancer pain is one of the most common complications in patients with malignant tumors， severely affecting their quality of life. Its pathogenesis involves complex interactions among the tumor microenvironment， peripheral sensitization， and central sensitization. The tumor microenvironment initiates peripheral pain sensitization by secreting algogenic mediators， activating ion channels and related receptor signaling pathways， driving abnormal osteoclast activation， and mediating neuro-immune crosstalk. Persistent nociceptive input further triggers increased excitability of central neurons， activation of glial cells， and neuroinflammatory cascade reactions， ultimately leading to central pain sensitization. Although traditional opioid drugs can alleviate pain to some extent， they still have many limitations， such as incomplete analgesia， drug tolerance， and adverse reactions. In recent years， traditional Chinese medicine （TCM） compounds have made continuous progress in the treatment of cancer pain. Studies have shown that they can not only effectively relieve cancer pain and reduce the dosage of opioids but also significantly improve patients' quality of life. TCM treatment of cancer pain follows the principle of syndrome differentiation and treatment. Based on this， targeted therapeutic principles have been proposed， including promoting blood circulation， removing stasis， regulating Qi， and unblocking collaterals； tonifying the kidney， replenishing essence， warming Yang， and dispersing cold， activating blood， resolving phlegm， detoxifying， and dispersing nodules， as well as strengthening the body， replenishing deficiency， and harmonizing Qi and blood. Modern research indicates that TCM compounds can exert synergistic effects through multiple pathways， inhibiting inflammatory responses， regulating nerve conduction， intervening in bone metabolism and related gene expression， thereby producing anti-inflammatory and bone-protective effects to achieve the goal of alleviating cancer pain. This article systematically elaborates on the pathogenesis of cancer pain， the clinical application of TCM in treating cancer pain， and its related mechanisms of action， aiming to provide a theoretical basis and new strategies for the integration of TCM into comprehensive cancer pain management.