BACKGROUND:Nanocell vesicles possess functions such as re-epithelialization,antioxidation,anti-inflammation,and regulation of extracellular matrix remodeling.Meanwhile,apoptotic bodies have the immunomodulatory effects.Therefore,the combination of the two to form nanofusion vesicles can synergistically promote the healing of diabetic skin wounds.OBJECTIVE:To elucidate the impact of nanofusion vesicles on skin wound healing in a diabetic murine model.METHODS:(1)Material preparation and characterization:The primary bone marrow mesenchymal stem cells of C57BL/6J neonatal mice and the neutrophil apoptotic bodies of C57BL/6J mice were isolated and extracted.The nanofusion vesicles were prepared by micro-extrusion mechanism.(2)In vitro experiment:MTT assay was used to detect the proliferative effect of different concentrations of nanofusion vesicles on NIH-3T3 cells and human umbilical vein endothelial cells.Reactive oxygen species fluorescence probe was used to detect the antioxidant effect of nano-fusion vesicles on NIH-3T3 cells treated with hydrogen peroxide(H2O2).The inhibitory effect of nanofusion vesicles on RAW 264.7 macrophage inflammation induced by lipopolyside was detected by real-time quantitative RT-qPCR.(3)In vivo experiment:36 male C57BL/6J mice were employed to develop a murine model of diabetes mellitus.Following the successful induction of diabetes,two circular full-thickness wounds,each with a diameter of 6 mm,were created on either side of the diabetic mice's spine using a skin punch.The mice were divided into three groups by random number table method.The control group was injected with 0.1 mL of phosphate buffer solution.The nanovesicle group was injected with 0.1 mL nanovesicles(25 μg/mL).The nanofusion vesicle group was injected with 0.1 mL nanofusion(25 μg/mL)vesicles.After treatment for three consecutive days,the wound healing and histomorphological changes were observed.RESULTS AND CONCLUSION:(1)In vitro experiment:nanofusion vesicles,when administered at concentrations ranging from 0 to 100 μg/mL,exhibited no toxic effects and promoted the proliferation of NIH-3T3 and HUVEC cell lines.Notably,a concentration of 25 μg/mL nanofusion vesicle significantly enhanced the proliferation of NIH-3T3 cells.Furthermore,the survival rate of human umbilical vein endothelial cells was observed to increase in correlation with escalating concentrations of nanofusion vesicles.Nanofusion vesicles had a good antioxidant effect.In comparison to the H2O2 group,the fluorescence signal indicative of reactive oxygen species was progressively diminished in both the nanovesicle group and the nanofusion vesicle group.Furthermore,nanofusion vesicles possessed anti-inflammatory capabilities,effectively mitigating the inflammatory response in macrophages triggered by lipopolysaccharide stimulation.(2)In vivo experiment:Hematoxylin-eosin and Masson's trichrome staining revealed that in comparison to the control group,both the nanovesicle group and the nanofusion vesicle group exhibited a significant increase in granulation tissue formation and collagen fiber deposition within the wounds by day 6.Notably,the nanofusion vesicle group displayed the most pronounced effects.On day 12,the wound of nanofusion vesicle group was significantly reduced,and the healing rate was significantly faster than that of other groups(P＜0.01),and the effect of promoting wound healing was the most significant.Our findings demonstrated that nanofusion vesicles exhibited superior pro-cell proliferative,antioxidant,and anti-inflammatory properties,thereby exerting a beneficial effect on the promotion of skin wound healing in diabetic mouse models.

BACKGROUND:Nanocell vesicles possess functions such as re-epithelialization,antioxidation,anti-inflammation,and regulation of extracellular matrix remodeling.Meanwhile,apoptotic bodies have the immunomodulatory effects.Therefore,the combination of the two to form nanofusion vesicles can synergistically promote the healing of diabetic skin wounds.OBJECTIVE:To elucidate the impact of nanofusion vesicles on skin wound healing in a diabetic murine model.METHODS:(1)Material preparation and characterization:The primary bone marrow mesenchymal stem cells of C57BL/6J neonatal mice and the neutrophil apoptotic bodies of C57BL/6J mice were isolated and extracted.The nanofusion vesicles were prepared by micro-extrusion mechanism.(2)In vitro experiment:MTT assay was used to detect the proliferative effect of different concentrations of nanofusion vesicles on NIH-3T3 cells and human umbilical vein endothelial cells.Reactive oxygen species fluorescence probe was used to detect the antioxidant effect of nano-fusion vesicles on NIH-3T3 cells treated with hydrogen peroxide(H2O2).The inhibitory effect of nanofusion vesicles on RAW 264.7 macrophage inflammation induced by lipopolyside was detected by real-time quantitative RT-qPCR.(3)In vivo experiment:36 male C57BL/6J mice were employed to develop a murine model of diabetes mellitus.Following the successful induction of diabetes,two circular full-thickness wounds,each with a diameter of 6 mm,were created on either side of the diabetic mice's spine using a skin punch.The mice were divided into three groups by random number table method.The control group was injected with 0.1 mL of phosphate buffer solution.The nanovesicle group was injected with 0.1 mL nanovesicles(25 μg/mL).The nanofusion vesicle group was injected with 0.1 mL nanofusion(25 μg/mL)vesicles.After treatment for three consecutive days,the wound healing and histomorphological changes were observed.RESULTS AND CONCLUSION:(1)In vitro experiment:nanofusion vesicles,when administered at concentrations ranging from 0 to 100 μg/mL,exhibited no toxic effects and promoted the proliferation of NIH-3T3 and HUVEC cell lines.Notably,a concentration of 25 μg/mL nanofusion vesicle significantly enhanced the proliferation of NIH-3T3 cells.Furthermore,the survival rate of human umbilical vein endothelial cells was observed to increase in correlation with escalating concentrations of nanofusion vesicles.Nanofusion vesicles had a good antioxidant effect.In comparison to the H2O2 group,the fluorescence signal indicative of reactive oxygen species was progressively diminished in both the nanovesicle group and the nanofusion vesicle group.Furthermore,nanofusion vesicles possessed anti-inflammatory capabilities,effectively mitigating the inflammatory response in macrophages triggered by lipopolysaccharide stimulation.(2)In vivo experiment:Hematoxylin-eosin and Masson's trichrome staining revealed that in comparison to the control group,both the nanovesicle group and the nanofusion vesicle group exhibited a significant increase in granulation tissue formation and collagen fiber deposition within the wounds by day 6.Notably,the nanofusion vesicle group displayed the most pronounced effects.On day 12,the wound of nanofusion vesicle group was significantly reduced,and the healing rate was significantly faster than that of other groups(P＜0.01),and the effect of promoting wound healing was the most significant.Our findings demonstrated that nanofusion vesicles exhibited superior pro-cell proliferative,antioxidant,and anti-inflammatory properties,thereby exerting a beneficial effect on the promotion of skin wound healing in diabetic mouse models.

With the continuous deepening of the concept of precision diagnosis and treatment for lung cancer, how to achieve higher efficiency and accuracy in the screening, diagnosis, and treatment pathways in clinical practice has become an important issue that urgently needs to be overcome. The current clinical difficulty lies in the fact that despite continuous advancements in imaging and molecular diagnostic technologies, there are still limitations in manual efficiency and subjective experience when it comes to massive data analysis and multi-scale feature extraction. Artificial intelligence (AI), especially algorithm systems based on deep learning, is an innovative technology capable of deeply empowering medical big data. This method utilizes algorithms such as convolutional neural networks, combined with radiomics, pathomics, and multi-modal data fusion analysis, demonstrating immense potential in early precise detection and benign-malignant differentiation of pulmonary nodules, digital pathological subtype recognition and non-invasive prediction of driver genes, precise 3D surgical planning and automatic delineation of radiotherapy target volumes, as well as dynamic risk warning during follow-up. This innovative technology provides a brand-new solution for realizing intelligent and individualized lung cancer diagnosis and treatment models. This consensus, based on the latest evidence from evidence-based medicine and combined with the development trends in the AI field and real-world clinical needs, was ultimately formed by gathering the consensus opinions of multidisciplinary experts in radiology, pathology, thoracic surgery, and other fields. The main content covers the application specifications of AI in the three core scenarios of lung cancer screening, diagnosis, and treatment, the technical standards for data collection and algorithm validation, as well as the ethical and regulatory challenges faced at the current stage. It aims to clarify the applicable boundaries of AI as a clinical auxiliary decision support tool, providing scientific guidance and standardized exploration directions for peers currently engaged in or planning to carry out AI-assisted clinical diagnosis, treatment, and translation of lung cancer.

Aim To establish and evaluate an alternative meth-od for detecting skin sensitization of cosmetics based on local lymph node assay using bromodeoxyuridine(BrdU)with flow cytometry(FCM).Methods(1)25％hexyl cinnamic alde-hyde(HCA)was chosen as a positive control with an acetone:olive oil(4∶1,V/V,AOO)mixture as a vehicle control for the experiment.The dorsal sides of both ears of mice were treated with test solutions on day 1,day 2,and day 3.Brdu solution was injected inter-peritoneally on day 5.On day 6,the bilateral ears and mandibular lymph nodes were excised,and the number of Brdu positive cells was measured by flow cytometry.The stim-ulation index(SI)was calculated to identify whether it was ≥3,in order to establish the method of LLNA:Brdu-FCM.(2)BrdU-FCM test was conducted using a blind method with the fif-teen reference substances listed in OECD TG429 whose skin sensitization potentials were known.The test substances were dissolved in AOO,N,N-dimethylformamide(DMF)or dimeth-yl sulfoxide(DMSO)at three different concentrations.Tests were performed the same as above.SI and EC2.7 were calculat-ed to evaluate whether the test substance was categorized as a skin sensitizer.The reliability and accuracy of the method were validated by comparing the classification of test substances with that in OECD TG429.Results The SI for 25％HCA was 3.9,showing positive in the skin sensitization test.It demonstrated that the LLNA:Brdu-FCM test method was properly implemen-ted.Nine test substances(2,4-dinitrochlorobenzene,4-pheny-lenediamine,cobalt chloride,2-mercaptobenzothiazole,hexyl-cinnamaldehyde,eugenol,phenyl benzoate,cinnamic alcohol,imidazolidinyl urea)were positive,and six test substances(methyl methacrylate,chlorobenzene,isopropanol,lactic acid,methyl salicylate,salicylic acid)were negative.The method was evaluated with sensitivity of 90％,specificity of 100％,positive prediction rate of 100％,negative prediction rate of 83％,false positive rate of 0％,false negative rate of 17％and accuracy of 93％.The LLNA:BrdU-FCM assay could correctly categorize the test substances that were skin sensitizers or non-sensitizers.Conclusion The LLNA:BrdU-FCM assay appears to be a relia-ble predictor of skin sensitization protential of chemicals,and it is expected to an alternative method for identifying skin sensitization as a supplementary in safety evaluation of cosmetic ingredient.

BACKGROUND:MXene nanoparticles,due to their unique hydrophilicity,biocompatibility,and antibacterial properties,are widely used in wound,tumor,nerve repair,and cardiovascular treatments.However,it is still unclear what effect MXene nanoparticles have on diabetic wound healing.OBJECTIVE:To investigate the in vitro antioxidant,anti-inflammatory and photothermal antibacterial properties of MXene nanoparticles Ti3C2Tx as well as their effect on wound repair in diabetic mice.METHODS:(1)In vitro experiments:The cytotoxicity of Ti3C2Tx nanoparticles on mouse fibroblasts(NIH-3T3)at various concentrations was evaluated using the methyl thiazolyl tetrazolium(MTT)assay.NIH-3T3 cells were exposed to H2O2,and the MTT assay was used to detect the protective effects of different mass concentrations of Ti3C2Tx on NIH-3T3 cells.NIH-3T3 cells were exposed to H2O2,and the effect of Ti3C2Tx(20 μg/mL)on the generation of reactive oxygen species in NIH-3T3 cells was analyzed under illumination(or no illumination)treatment.RAW264.7 macrophages were divided into three groups:control group,lipopolysaccharide group,and lipopolysaccharide+Ti3C2Tx group.Real-time quantitative PCR was used to detect the expression of specific genes(CD86,interleukin 6,CD206,arginase 1)in the cells.Escherichia coli(or Staphylococcus aureus)were divided into three groups:control group,Ti3C2Tx group,and Ti3C2Tx illumination group.The bacterial survival rate was calculated by plate colony counting method.(2)In vivo experiments:Streptozotocin was administered intraperitoneally to ICR mice to induce a diabetic condition.After successful modeling,a full-thickness skin defect wound was created on the back of the mice using a circular punch.The experiment was divided into three groups:control group(n=6),Ti3C2Tx group(n=6),and Ti3C2Tx illumination group(n=6).The wound healing was observed,and CD31 and CD206 immunohistochemical staining of wound tissue was performed on day 7 after intervention.Hematoxylin-eosin staining and Masson staining of wound tissue were performed on days 7 and 14 after intervention.Ti3C2Tx solution was injected subcutaneously into ICR mice.After illumination(or non-illumination)exposure,the toxic effects of Ti3C2Tx on mice were analyzed by blood biochemical detection.RESULTS AND CONCLUSION:(1)In vitro experiments:Ti3C2Tx showed no cytotoxicity on NIH-3T3 cells at mass concentrations ranging from 5-160 μg/mL.It increased the survival rate of NIH-3T3 cells at a mass concentration of 20 μg/mL.Ti3C2Tx at 10-80 μg/mL significantly improved the survival rate of NIH-3T3 cells under H2O2 intervention.Ti3C2Tx significantly inhibited the generation of reactive oxygen species in NIH-3T3 cells under the intervention of H2O2,and illumination treatment further enhanced the effect of Ti3C2Tx on inhibiting the generation of reactive oxygen species.Ti3C2Tx effectively inhibited macrophage inflammation induced by lipopolysaccharide and promoted the transformation of cells into M2 macrophages with anti-inflammatory properties.Both Ti3C2Tx and Ti3C2Tx illumination significantly inhibited the growth of Escherichia coli and Staphylococcus aureus,and the inhibitory effect of Ti3C2Tx illumination was more significant.(2)In vivo experiments:Gross and histological analyses of the wound surface showed that both Ti3C2Tx and Ti3C2Tx illumination promoted wound healing in diabetic mice,and the promotion effect of Ti3C2Tx irradiation was more significant.Immunohistochemical staining results showed that both Ti3C2Tx and Ti3C2Tx illumination inhibited the inflammatory response in diabetic wounds and promoted angiogenesis,and the effect of Ti3C2Tx illumination was more significant.Blood biochemical test results showed that Ti3C2Tx and illumination had no obvious toxic effects on mice.(3)These results indicate that Ti3C2Tx nanoparticles efficiently promote the healing of skin wounds in a diabetic mouse model through antioxidation,anti-inflammation,and antibacterial actions via photothermal effects.

Objective To develop a method of pulsed direct current electrospray ionization mass spectrometry(pulsed-dc-ESI-MS)for rapid detection of 4 kinds of amphetamines in saliva.Methods Saliva samples were adjusted to optimal pH using NaOH,followed by protein precipitation with anhydrous magnesium sulfate and liquid-liquid extraction with ethyl acetate.The supernatant was then analyzed via pulsed-dc-ESI-MS.Results The limits of detection were 0.01～0.5 ng/mL and the limits of quantitative were 1.0～5.0 ng/mL.In addition,in the concentration range,4 amphetamines have good linear relationships,the correlation coefficients(R2)were all greater than 0.999,the recoveries of 97.21%～104.70%and the relative standard deviations(RSDs)were less than 10%.Conclusion The method has the advantages of simple operation,fast detection,high sensitivity,selectivity and good stability.It can be used for on-site rapid detection of amphetamines in saliva.

Objective:To explore the clinical efficacy of the first dorsal metatarsal artery pedicled lateral toe bilobed flap in repairing the finger pulp defects of two adjacent fingers.Methods:This study was a retrospective observational study. From January 2018 to December 2022, 9 patients with finger pulp defects in two adjacent fingers who met the inclusion criteria were admitted to the Department of Burns and Plastic Surgery of the 988 th Hospital of Joint Logistics Support Force of PLA, including 6 males and 3 females, aged 26 to 48 years. The injured fingers were the index finger and middle finger (5 cases) or the middle finger and ring finger (4 cases). After debridement, the wound area of a single finger ranged from 1.2 cm×0.8 cm to 3.2 cm×2.8 cm. The finger pulp defects of two adjacent fingers were repaired with the first dorsal metatarsal artery pedicled lateral toe bilobed flap, and the two adjacent fingers were sutured together. The area of single flap ranged from 1.5 cm×1.0 cm to 3.5 cm×3.0 cm. The wound in the flap donor site was sutured directly or repaired with full-thickness skin graft from the groin region. The finger separation surgery was performed 3 weeks after surgery. The survival and blood supply of flaps, and survival of skin grafts and wound healing of the donor sites were observed after surgery. During follow-up, the texture, sliding, and shape of the flap, movement function of the finger, and the shape and function of the foot donor site were observed. At the last follow-up, the sensory of the flap was evaluated according to the sensory evaluation standard of the British Medical Research Council, and the hand function was evaluated according to the functional evaluation trial standard for severed finger replantation of the Hand Surgery Society of the Chinese Medical Association. Results:After surgery, all the flaps of 9 patients survived without vascular crisis. The flaps were soft in texture and good in shape. One patient had partial necrosis at the edge of the skin graft in the toe, and the wound healed after dressing change; the skin grafts in the toe in the other 8 patients survived, and the wounds healed well. During follow-up of 12 to 18 months after surgery, the flaps had soft texture, good elasticity, low sliding, and good shape. The finger movement function was normal. The wound in foot donor site recovered well without ulceration and deformity, and walking was not affected. At the last follow-up, the sensation of the flaps was sensitive, of which 8 flaps reached S3 and 10 flaps reached S3 + in sensation, and the two-point discrimination distance of the flaps was 9-13 mm. The functional scores of the affected fingers were 85 to 95, all of which were excellent. Conclusions:The first dorsal metatarsal artery pedicled lateral toe bilobed flap can repair finger pulp defects of two adjacent fingers at the same time, and the appearance, sensation, and function of the affected fingers recovered well after surgery, with less damage to the foot donor site. It is one of good methods to repair finger pulp defects of two adjacent fingers in clinic.

BACKGROUND:MXene nanoparticles,due to their unique hydrophilicity,biocompatibility,and antibacterial properties,are widely used in wound,tumor,nerve repair,and cardiovascular treatments.However,it is still unclear what effect MXene nanoparticles have on diabetic wound healing.OBJECTIVE:To investigate the in vitro antioxidant,anti-inflammatory and photothermal antibacterial properties of MXene nanoparticles Ti3C2Tx as well as their effect on wound repair in diabetic mice.METHODS:(1)In vitro experiments:The cytotoxicity of Ti3C2Tx nanoparticles on mouse fibroblasts(NIH-3T3)at various concentrations was evaluated using the methyl thiazolyl tetrazolium(MTT)assay.NIH-3T3 cells were exposed to H2O2,and the MTT assay was used to detect the protective effects of different mass concentrations of Ti3C2Tx on NIH-3T3 cells.NIH-3T3 cells were exposed to H2O2,and the effect of Ti3C2Tx(20 μg/mL)on the generation of reactive oxygen species in NIH-3T3 cells was analyzed under illumination(or no illumination)treatment.RAW264.7 macrophages were divided into three groups:control group,lipopolysaccharide group,and lipopolysaccharide+Ti3C2Tx group.Real-time quantitative PCR was used to detect the expression of specific genes(CD86,interleukin 6,CD206,arginase 1)in the cells.Escherichia coli(or Staphylococcus aureus)were divided into three groups:control group,Ti3C2Tx group,and Ti3C2Tx illumination group.The bacterial survival rate was calculated by plate colony counting method.(2)In vivo experiments:Streptozotocin was administered intraperitoneally to ICR mice to induce a diabetic condition.After successful modeling,a full-thickness skin defect wound was created on the back of the mice using a circular punch.The experiment was divided into three groups:control group(n=6),Ti3C2Tx group(n=6),and Ti3C2Tx illumination group(n=6).The wound healing was observed,and CD31 and CD206 immunohistochemical staining of wound tissue was performed on day 7 after intervention.Hematoxylin-eosin staining and Masson staining of wound tissue were performed on days 7 and 14 after intervention.Ti3C2Tx solution was injected subcutaneously into ICR mice.After illumination(or non-illumination)exposure,the toxic effects of Ti3C2Tx on mice were analyzed by blood biochemical detection.RESULTS AND CONCLUSION:(1)In vitro experiments:Ti3C2Tx showed no cytotoxicity on NIH-3T3 cells at mass concentrations ranging from 5-160 μg/mL.It increased the survival rate of NIH-3T3 cells at a mass concentration of 20 μg/mL.Ti3C2Tx at 10-80 μg/mL significantly improved the survival rate of NIH-3T3 cells under H2O2 intervention.Ti3C2Tx significantly inhibited the generation of reactive oxygen species in NIH-3T3 cells under the intervention of H2O2,and illumination treatment further enhanced the effect of Ti3C2Tx on inhibiting the generation of reactive oxygen species.Ti3C2Tx effectively inhibited macrophage inflammation induced by lipopolysaccharide and promoted the transformation of cells into M2 macrophages with anti-inflammatory properties.Both Ti3C2Tx and Ti3C2Tx illumination significantly inhibited the growth of Escherichia coli and Staphylococcus aureus,and the inhibitory effect of Ti3C2Tx illumination was more significant.(2)In vivo experiments:Gross and histological analyses of the wound surface showed that both Ti3C2Tx and Ti3C2Tx illumination promoted wound healing in diabetic mice,and the promotion effect of Ti3C2Tx irradiation was more significant.Immunohistochemical staining results showed that both Ti3C2Tx and Ti3C2Tx illumination inhibited the inflammatory response in diabetic wounds and promoted angiogenesis,and the effect of Ti3C2Tx illumination was more significant.Blood biochemical test results showed that Ti3C2Tx and illumination had no obvious toxic effects on mice.(3)These results indicate that Ti3C2Tx nanoparticles efficiently promote the healing of skin wounds in a diabetic mouse model through antioxidation,anti-inflammation,and antibacterial actions via photothermal effects.

Aim To establish and evaluate an alternative meth-od for detecting skin sensitization of cosmetics based on local lymph node assay using bromodeoxyuridine(BrdU)with flow cytometry(FCM).Methods(1)25％hexyl cinnamic alde-hyde(HCA)was chosen as a positive control with an acetone:olive oil(4∶1,V/V,AOO)mixture as a vehicle control for the experiment.The dorsal sides of both ears of mice were treated with test solutions on day 1,day 2,and day 3.Brdu solution was injected inter-peritoneally on day 5.On day 6,the bilateral ears and mandibular lymph nodes were excised,and the number of Brdu positive cells was measured by flow cytometry.The stim-ulation index(SI)was calculated to identify whether it was ≥3,in order to establish the method of LLNA:Brdu-FCM.(2)BrdU-FCM test was conducted using a blind method with the fif-teen reference substances listed in OECD TG429 whose skin sensitization potentials were known.The test substances were dissolved in AOO,N,N-dimethylformamide(DMF)or dimeth-yl sulfoxide(DMSO)at three different concentrations.Tests were performed the same as above.SI and EC2.7 were calculat-ed to evaluate whether the test substance was categorized as a skin sensitizer.The reliability and accuracy of the method were validated by comparing the classification of test substances with that in OECD TG429.Results The SI for 25％HCA was 3.9,showing positive in the skin sensitization test.It demonstrated that the LLNA:Brdu-FCM test method was properly implemen-ted.Nine test substances(2,4-dinitrochlorobenzene,4-pheny-lenediamine,cobalt chloride,2-mercaptobenzothiazole,hexyl-cinnamaldehyde,eugenol,phenyl benzoate,cinnamic alcohol,imidazolidinyl urea)were positive,and six test substances(methyl methacrylate,chlorobenzene,isopropanol,lactic acid,methyl salicylate,salicylic acid)were negative.The method was evaluated with sensitivity of 90％,specificity of 100％,positive prediction rate of 100％,negative prediction rate of 83％,false positive rate of 0％,false negative rate of 17％and accuracy of 93％.The LLNA:BrdU-FCM assay could correctly categorize the test substances that were skin sensitizers or non-sensitizers.Conclusion The LLNA:BrdU-FCM assay appears to be a relia-ble predictor of skin sensitization protential of chemicals,and it is expected to an alternative method for identifying skin sensitization as a supplementary in safety evaluation of cosmetic ingredient.

BACKGROUND:Studies have shown that different durations of pressure application on normal muscles can produce varying physiological responses.OBJECTIVE:To explore the expression levels of inflammatory factors tumor necrosis factor α and nuclear κB in skeletal muscle under different pressure durations.METHODS:Twenty healthy male SPF-grade Sprague-Dawley rats were randomly divided into four groups:control group,10-second pressure group,20-second pressure group,and 30-second pressure group.The right leg of each rat was used for the experiment.The control group received no intervention,while rats in each pressure group were anesthetized by intraperitoneal injection of 2%pentobarbital sodium(35 mg/kg),and the thin femoral muscle of the rats was pressed continuously at a constant pressure of 200 kPa using a homemade mechanical pressure device for 10,20,and 30 seconds,respectively.Muscle tissue at the pressing site of the right hind limb was collected immediately after pressure.Hematoxylin-eosin staining was used to observe the morphological changes of skeletal muscle tissues and changes in the cross-sectional area of muscle fibers,and immunohistochemistry was used to detect the expression levels of tumor necrosis factor α and nuclear factor κB in rat skeletal muscle.RESULTS AND CONCLUSION:Hematoxylin-eosin staining results revealed that the pressure groups showed loosely arranged skeletal muscle fibers,reduced cross-sectional area and diameter,and enlarged intermuscular spaces.Compared with the control group,the cross-sectional area of muscle fibers was significantly reduced in the pressure groups(P<0.05),but there was no significant difference between the three pressure groups(P>0.05).The 10-second pressure group showed no significant presence of red blood cells in the interstitial spaces,while the 20-second pressure group exhibited a small amount of red blood cells,and the 30-second pressure group showed capillary dilation with red blood cells in the interstitial spaces.The expression level of tumor necrosis factor α in the 30-second pressure group was significantly higher than that in the control group(P<0.05).The expression level of nuclear factor κB in skeletal muscle showed no significant difference among groups(P>0.05).To conclude,skeletal muscle undergoes morphological changes and reduced cross-sectional area after pressure at 200 kPa,but there is no significant difference among the 10-,20-,and 30-second pressure groups.As the duration of pressure increases to 30 seconds,the inflammatory factor tumor necrosis factor α is activated,but nuclear factor κB remains unaffected,suggesting that inflammatory factors may express under short-term pressure,while transcription factors show no significant change.