ObjectiveTo investigate the potential mechanism of Danggui Buxuetang （DBT） in the treatment of vascular dementia （VAD）. MethodsSixty male SD rats were randomly assigned to the sham-operated group， model group， DBT low-， medium-， and high-dose groups， and the donepezil group. Except for the sham-operated group， rats in all other groups underwent bilateral common carotid artery ligation. After successful modeling， DBT was administered at doses of 9.2， 18.4， 36.8 g·kg^-1 for the low-， medium-， and high-dose groups， respectively， while the donepezil group received 3 mg·kg^-1 donepezil solution by gavage once daily. After 4 consecutive weeks of drug treatment， rats underwent the Morris water maze test， novel object recognition test， Nissl staining to observe hippocampal neurons， and immunofluorescence staining to detect the expression of neuronal nuclear protein （NeuN） in the hippocampus. Western blot was used to assess the expression of PTEN-induced kinase 1 （PINK1）， Parkin， microtubule-associated protein 1 light chain 3Ⅱ （LC3Ⅱ）， B-cell lymphoma-2 （Bcl-2）， and Bcl-2-associated X protein （Bax）. Transmission electron microscopy was used to observe hippocampal neuronal ultrastructure. Real-time PCR was used to detect the expression of NADPH oxidase subunits p22^phox and p47^phox in hippocampal tissues. The levels of malondialdehyde （MDA）， glutathione （GSH）， superoxide dismutase （SOD）， and total antioxidant capacity were measured to evaluate oxidative stress levels. ResultsIn the Morris water maze test， escape latency changed significantly over time in all groups except the model group. Compared with the sham-operated group， the model group showed significantly prolonged escape latency （P<0.01）. Compared with the model group， rats in the DBT groups and the donepezil group exhibited significantly shorter escape latency （P<0.05， P<0.01）. The number of crossings over the original platform was significantly reduced in the model group compared with the sham-operated group （P<0.01）， whereas rats in the DBT and donepezil groups showed significantly increased platform crossings compared with the model group （P<0.05， P<0.01）. Compared with the sham-operated group， exploration time of new objects was significantly reduced in the model group （P<0.01）. Compared with the model group， exploration time of new objects increased significantly in the medium- and high-dose DBT groups and the donepezil group （P<0.05， P<0.01）， while no significant change was observed in the low-dose DBT group. Compared with the high-dose DBT group， rats in the donepezil group had significantly prolonged escape latency and reduced platform crossings and new-object exploration time （P<0.05）. Nissl staining showed decreased density of healthy neurons in the CA1 and CA3 regions of the hippocampus in the model group， with loss of Nissl bodies and nuclear atrophy or disappearance. In the high-dose DBT group， neuronal density in CA1 and CA3 increased， with neurons arranged closely and displaying normal morphology. Immunofluorescence showed that compared with the sham-operated group， the hippocampal NeuN⁺ cell count in the VAD model group was significantly decreased（P<0.01）， compared with the VAD model group， the hippocampal NeuN⁺ cell count in the high-dose DBT group was significantly increased（P<0.01）. Compared with the sham-operated group， the expression of PINK1， Parkin， LC3Ⅱ， and Bax proteins was significantly increased（P<0.01）， while the expression of Bcl-2 was significantly decreased in the VAD model group（P<0.01）. Compared with the VAD model group， the high-dose DBT group showed significantly decreased expression of PINK1， Parkin， LC3Ⅱ， and Bax proteins（P<0.01）and significantly upregulated Bcl-2 expression（P<0.01）. The medium-dose DBT group exhibited significantly reduced expression of Parkin， LC3Ⅱ， and Bax proteins（P<0.05，P<0.01） and significantly increased Bcl-2 expression（P<0.01）， while no statistically significant differences were observed in the low-dose DBT group. Transmission electron microscopy showed mitochondrial pyknosis， thickened cristae， increased electron density， and the presence of mitochondrial autophagy in the model group. In contrast， hippocampal neurons in the high-dose DBT group contained abundant mitochondria with intact morphology， clear cristae， and uniform matrix. Compared with the sham-operated group， total antioxidant capacity， SOD activity， and GSH levels were significantly decreased， while MDA levels were significantly increased in the model group （P<0.01）. Compared with the model group， total antioxidant capacity and antioxidant levels （SOD， GSH） increased significantly， and MDA decreased significantly in the medium- and high-dose DBT groups （P<0.01）， while no significant changes were observed in the low-dose DBT group. Compared with the sham-operated group， mRNA expression of p22^phox and p47^phox was significantly increased in the model group （P<0.01）. Compared with the model group， expression of p22^phox and p47^phox was significantly decreased in the DBT groups （P<0.05， P<0.01）. ConclusionDBT may exert neuroprotective effects by regulating PINK1/Parkin-mediated mitochondrial autophagy， thereby improving learning and memory abilities and treating VAD.

ObjectiveTo investigate the molecular mechanism by which Yifei Xuanfei Jiangzhuo prescription regulates the nuclear factor-κB （NF-κB）/NOD-like receptor protein 3 （NLRP3） signaling pathway to improve neuronal function in vascular dementia （VaD） rats. MethodsA VaD model was established by intermittently clamping the bilateral common carotid arteries （CCA） combined with bilateral vascular occlusion （2-VO）. Eighty-four SD rats were randomly divided into a blank group， sham group， model group， piracetam group （0.2 g·kg^-1）， and low-， medium-， and high-dose Yifei Xuanfei Jiangzhuo prescription groups （6.09， 12.18， and 24.36 g·kg^-1）. Drug administration began on day 7 after surgery， once daily for 28 consecutive days. Behavioral experiments were used to evaluate learning and spatial memory. Hematoxylin-eosin （HE） staining was applied to observe pathological morphological changes in the CA1 region of the hippocampus. Transmission electron microscopy was used to examine the ultrastructure of hippocampal neurons. Terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） was used to detect neuronal apoptosis in the CA1 region. Immunohistochemistry was performed to determine the positive expression rate of neuronal nuclear antigen （NeuN）. Immunofluorescence single staining was used to assess nuclear expression of NF-κB p65 in brain tissue. Western blot was used to detect the protein expression levels of inhibitor of κB kinase （IKK）， NF-κB p65， NLRP3， Caspase-1， apoptosis-associated speck-like protein （ASC）， and interleukin-1β （IL-1β）. ResultsCompared with the blank group， the model group showed a significant reduction in platform-crossing frequency （P0.01）， aggravated hippocampal injury， a significant increase in neuronal apoptosis （P0.05）， decreased NeuN positivity in the CA1 region （P0.05）， increased nuclear expression of NF-κB p65 （P0.05）， and significantly elevated expression of p-IKK， p-NF-κB p65， NLRP3， cleaved Caspase-1， ASC， and cleaved IL-1β （P0.05）. Compared with the model group， all drug-treated groups improved learning and spatial memory in VaD rats， alleviated hippocampal pathological injury and neuronal apoptosis， and protected neuronal ultrastructure. Yifei Xuanfei Jiangzhuo prescription at doses of 12.18 and 24.36 g·kg^-1 reduced hippocampal expression levels of p-IKK， p-NF-κB p65， NLRP3， Caspase-1， ASC， and cleaved IL-1β in VaD rats （P0.05）， showing dose-dependent inhibition of the NF-κB/NLRP3 signaling pathway. ConclusionYifei Xuanfei Jiangzhuo prescription may exert neuroprotective effects by regulating the NF-κB/NLRP3 signaling pathway， thereby reducing neuroinflammation and inhibiting hippocampal neuronal apoptosis.

ObjectiveTo explore the effects of Yimei Baijiang formula （YMBJF） on colitis-associated colorectal cancer （CAC） and the nuclear factor kappaB （NF-κB） signaling pathway in mice. MethodsSixty male Balb/c mice of 4-6 weeks old were randomized into 6 groups： Normal， model， capecitabine （0.83 g·kg^-1）， and low-， medium-， and high-dose （4.63， 9.25， 18.50 g·kg^-1， respectively） YMBJF. The mouse model of CAC was established by combining azoxymethane （AOM， 10 mg·kg^-1） and dextran sulfate sodium （DSS， 2%）. At the 5^th week after the start of modeling， the capecitabine group and the YMBJF groups were respectively administrated with the corresponding doses of drugs by gavage once a day for a total of 6 weeks. The body weights and general conditions of mice were measured and observed， and the disease activity index （DAI） was scored. The tumors in the colorectal tissue were counted， and the colorectal length was measured. The histological features of the colorectal tissue in each group of mice were observed by hematoxylin-eosin （HE） staining. The levels of inflammatory cytokines including interleukin-6 （IL-6）， interleukin-1β （IL-1β）， and tumor necrosis factor-α （TNF-α） in the serum were determined by enzyme-linked immunosorbent assay （ELISA）. The expression and localization of proliferating cell nuclear antigen-67 （Ki67）， proliferating cell nuclear antigen （PCNA）， and phosphorylated nuclear transcription factor-κB p65 （p-NF-κB p65） proteins were observed by immunohistochemistry （IHC）. The apoptosis of tumor cells was observed by the TUNEL assay. The mRNA levels of IL-6，IL-1β， TNF-α， nuclear transcription factor-κB p65 （NF-κB p65）， NF-κB inhibitor alpha （IκBα）， B-cell lymphoma-2 （Bcl-2）， and Bcl-2-associated X protein （Bax） in the colorectal tissue were quantified by Real-time polymerase chain reaction（Real-time PCR）. The protein levels of NF-κB p65， phosphorylated （p）-NF-κB p65， IκBα， p-IκBα， Bcl-2， and Bax in the colorectal tissue were determined by Western blot. ResultsCompared with the model group， each YMBJF group showed decreases in DAI and tumor number （P0.01）， and the medium-dose and high-dose YMBJF groups showed increases in colorectal length （P0.05）. In addition， each YMBJF group showed alleviated colorectal mucosal pathological injury， declined levels of IL-6， IL-1β， and TNF-α in the serum （P0.05）， reduced expression of Ki67 and PCNA （P0.01）， and down-regulated expression of p-NF-κB p65 （P0.05）. The apoptosis in the medium-dose and high-dose YMBJF groups increased （P0.01）. Each YMBJF group and the capecitabine group showed down-regulated mRNA levels of IL-1β， TNF-α， IL-6， NF-κB p65， and Bcl-2 （P0.05） and up-regulated mRNA levels of IκBα and Bax （P0.05）. The mRNA level of IκBα was up-regulated， and that of Bcl-2 was down-regulated （P0.05） in the high-dose YMBJF group. The protein levels of p-IκBα and Bcl-2 were down-regulated （P0.05） in each YMBJF group. The protein levels of IκBα and Bax were up-regulated in the medium-dose and high-dose YMBJF groups （P0.01）， while those of NF-κB p65 and p-NF-κB p65 were down-regulated （P0.05）. ConclusionYMBJF can reduce the number of tumors， reduce the levels of inflammatory factors， promote tumor cell apoptosis， and inhibit tumor cell proliferation by regulating the direct effector molecules of the NF-κB signaling pathway in the mouse model of CRC.

ObjectiveTo investigate the molecular mechanism by which Yifei Xuanfei Jiangzhuo prescription regulates the nuclear factor-κB （NF-κB）/NOD-like receptor protein 3 （NLRP3） signaling pathway to improve neuronal function in vascular dementia （VaD） rats. MethodsA VaD model was established by intermittently clamping the bilateral common carotid arteries （CCA） combined with bilateral vascular occlusion （2-VO）. Eighty-four SD rats were randomly divided into a blank group， sham group， model group， piracetam group （0.2 g·kg^-1）， and low-， medium-， and high-dose Yifei Xuanfei Jiangzhuo prescription groups （6.09， 12.18， and 24.36 g·kg^-1）. Drug administration began on day 7 after surgery， once daily for 28 consecutive days. Behavioral experiments were used to evaluate learning and spatial memory. Hematoxylin-eosin （HE） staining was applied to observe pathological morphological changes in the CA1 region of the hippocampus. Transmission electron microscopy was used to examine the ultrastructure of hippocampal neurons. Terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） was used to detect neuronal apoptosis in the CA1 region. Immunohistochemistry was performed to determine the positive expression rate of neuronal nuclear antigen （NeuN）. Immunofluorescence single staining was used to assess nuclear expression of NF-κB p65 in brain tissue. Western blot was used to detect the protein expression levels of inhibitor of κB kinase （IKK）， NF-κB p65， NLRP3， Caspase-1， apoptosis-associated speck-like protein （ASC）， and interleukin-1β （IL-1β）. ResultsCompared with the blank group， the model group showed a significant reduction in platform-crossing frequency （P0.01）， aggravated hippocampal injury， a significant increase in neuronal apoptosis （P0.05）， decreased NeuN positivity in the CA1 region （P0.05）， increased nuclear expression of NF-κB p65 （P0.05）， and significantly elevated expression of p-IKK， p-NF-κB p65， NLRP3， cleaved Caspase-1， ASC， and cleaved IL-1β （P0.05）. Compared with the model group， all drug-treated groups improved learning and spatial memory in VaD rats， alleviated hippocampal pathological injury and neuronal apoptosis， and protected neuronal ultrastructure. Yifei Xuanfei Jiangzhuo prescription at doses of 12.18 and 24.36 g·kg^-1 reduced hippocampal expression levels of p-IKK， p-NF-κB p65， NLRP3， Caspase-1， ASC， and cleaved IL-1β in VaD rats （P0.05）， showing dose-dependent inhibition of the NF-κB/NLRP3 signaling pathway. ConclusionYifei Xuanfei Jiangzhuo prescription may exert neuroprotective effects by regulating the NF-κB/NLRP3 signaling pathway， thereby reducing neuroinflammation and inhibiting hippocampal neuronal apoptosis.

ObjectiveTo explore the effects of Yimei Baijiang formula （YMBJF） on colitis-associated colorectal cancer （CAC） and the nuclear factor kappaB （NF-κB） signaling pathway in mice. MethodsSixty male Balb/c mice of 4-6 weeks old were randomized into 6 groups： Normal， model， capecitabine （0.83 g·kg^-1）， and low-， medium-， and high-dose （4.63， 9.25， 18.50 g·kg^-1， respectively） YMBJF. The mouse model of CAC was established by combining azoxymethane （AOM， 10 mg·kg^-1） and dextran sulfate sodium （DSS， 2%）. At the 5^th week after the start of modeling， the capecitabine group and the YMBJF groups were respectively administrated with the corresponding doses of drugs by gavage once a day for a total of 6 weeks. The body weights and general conditions of mice were measured and observed， and the disease activity index （DAI） was scored. The tumors in the colorectal tissue were counted， and the colorectal length was measured. The histological features of the colorectal tissue in each group of mice were observed by hematoxylin-eosin （HE） staining. The levels of inflammatory cytokines including interleukin-6 （IL-6）， interleukin-1β （IL-1β）， and tumor necrosis factor-α （TNF-α） in the serum were determined by enzyme-linked immunosorbent assay （ELISA）. The expression and localization of proliferating cell nuclear antigen-67 （Ki67）， proliferating cell nuclear antigen （PCNA）， and phosphorylated nuclear transcription factor-κB p65 （p-NF-κB p65） proteins were observed by immunohistochemistry （IHC）. The apoptosis of tumor cells was observed by the TUNEL assay. The mRNA levels of IL-6，IL-1β， TNF-α， nuclear transcription factor-κB p65 （NF-κB p65）， NF-κB inhibitor alpha （IκBα）， B-cell lymphoma-2 （Bcl-2）， and Bcl-2-associated X protein （Bax） in the colorectal tissue were quantified by Real-time polymerase chain reaction（Real-time PCR）. The protein levels of NF-κB p65， phosphorylated （p）-NF-κB p65， IκBα， p-IκBα， Bcl-2， and Bax in the colorectal tissue were determined by Western blot. ResultsCompared with the model group， each YMBJF group showed decreases in DAI and tumor number （P0.01）， and the medium-dose and high-dose YMBJF groups showed increases in colorectal length （P0.05）. In addition， each YMBJF group showed alleviated colorectal mucosal pathological injury， declined levels of IL-6， IL-1β， and TNF-α in the serum （P0.05）， reduced expression of Ki67 and PCNA （P0.01）， and down-regulated expression of p-NF-κB p65 （P0.05）. The apoptosis in the medium-dose and high-dose YMBJF groups increased （P0.01）. Each YMBJF group and the capecitabine group showed down-regulated mRNA levels of IL-1β， TNF-α， IL-6， NF-κB p65， and Bcl-2 （P0.05） and up-regulated mRNA levels of IκBα and Bax （P0.05）. The mRNA level of IκBα was up-regulated， and that of Bcl-2 was down-regulated （P0.05） in the high-dose YMBJF group. The protein levels of p-IκBα and Bcl-2 were down-regulated （P0.05） in each YMBJF group. The protein levels of IκBα and Bax were up-regulated in the medium-dose and high-dose YMBJF groups （P0.01）， while those of NF-κB p65 and p-NF-κB p65 were down-regulated （P0.05）. ConclusionYMBJF can reduce the number of tumors， reduce the levels of inflammatory factors， promote tumor cell apoptosis， and inhibit tumor cell proliferation by regulating the direct effector molecules of the NF-κB signaling pathway in the mouse model of CRC.

As a pivotal strategy to alleviate the shortage of organ donors, xenotransplantation has achieved remarkable advances in both pre-clinical and clinical studies in recent years, driven by continuous optimization of gene modification techniques and immunosuppressive regimens. Nevertheless, clinical translation still confronts formidable challenges, including rejection and heightened infection risks, which severely compromise long-term graft survival. Consequently, the role of immunosuppressive regimens in xenotransplantation has become increasingly prominent. This article summarizes the mechanisms underlying xenogeneic immune rejection, the latest developments in immunosuppressive regimens, cutting-edge strategies for inducing immune tolerance and the major hurdles facing clinical xenotransplantation. It delves into potential optimization strategies and directions for future clinical research, aiming to offer theoretical insights and practical guidance for the safe and effective application of clinical xenotransplantation.

BACKGROUND:The reasonable implantation range of femoral prosthesis in unicompartmental knee arthroplasty in patients with osteoporosis has not been investigated,and previous studies have often been based on unicompartmental knee arthroplasty models in normal bone,with fewer mechanical studies in models with non-normal bone.Complications after unicompartmental knee arthroplasty have been shown to be highly associated with osteoporosis. OBJECTIVE:To analyze the biomechanical effects of the coronal inclination of the Sled fixed platform femoral prosthesis on unicompartmental knee arthroplasty in patients with osteoporosis and to find the correlation between osteoporosis and mid-and long-term complications after unicompartmental knee arthroplasty. METHODS:Based on the digital imaging technology to obtain the data of the knee joint and prosthesis,a normal bone knee model is then created by using specialized software such as Mimics and Geomagic studio.Based on a validated normal bone knee model,an osteoporotic knee model was created by changing the material parameters.Totally 14 unicompartmental knee arthroplasty finite element models were created using Sled fixed platform femoral prosthesis:standard position(0°),varus and valgus angles:3°,6°,9° in the normal bone and osteoporosis groups.Stress changes on the surface of polyethylene liner,cancellous bone under tibial prosthesis,and cortical bone were calculated and analyzed in all unicompartmental knee arthroplasty models. RESULTS AND CONCLUSION:(1)In the osteoporotic models,the high stress values of the polyethylene liner surface and the cancellous bone under the tibial prosthesis increased with the increase of the tilt angle of the femoral prosthesis,and the high stress values of the cortical bone surface under the tibial prosthesis increased with the increase of the prosthesis valgus angles and decreased with the increase of the varus angles.(2)For the polyethylene liner surface as well as the subcortical bone surface of the tibial prosthesis,the high stress values of the models for each inclination angle in the osteoporosis group were greater than those of the corresponding models in the normal bone group.For the surface of the cancellous bone under the tibial prosthesis,the high stress values of the tilt angle models of the osteoporosis groups were smaller than those of the normal bone groups.(3)Osteoporosis may cause biomechanical abnormalities in the internal structures of the knee after unicondylar replacement,increasing the potential risk of postoperative aseptic loosening of the prosthesis and periprosthetic fractures.Varus and valgus of the femoral prosthesis in the coronal plane should be avoided as much as possible when performing medial unicompartmental knee arthroplasty with a Sled fixation platform in osteoporotic knees.

BACKGROUND:The biomechanical analysis of scoliosis cases is limited,with only independent analysis focusing on the spine or lower limbs,thus lacking a comprehensive evaluation of the multidimensional body.As a result,it becomes challenging to reflect the movement relationship between the trunk and lower limbs during daily activities,which hinders comprehensive clinical treatment guidance. OBJECTIVE:To explore the relationship between different segments of the spine and the kinematics/kinetics of the lower limbs during gait activities by measuring spinal kinematics in scoliosis patients,to provide a comprehensive and multi-level assessment of the biomechanical differences between scoliosis patients and the normal population,consequently offering evidence-based guidance for the prevention and treatment of scoliosis. METHODS:A cross-sectional study was conducted from July 2020 to June 2021 at the Rehabilitation Hospital Affiliated to Fujian University of Traditional Chinese Medicine in Fuzhou University City.A total of 28 scoliosis patients and 28 normal individuals in the same age group were included.Three-dimensional motion capture system was used to capture gait kinematic data at a sampling frequency of 100 Hz.Two force plates(AMTI 400600,sampling frequency 1 500 Hz)were embedded in a 10-meter-long 2.4-meter-wide level ground walkway(with an effective data collection length of 4 m)to collect kinetic data.The differences in spatial-temporal parameters,kinematics,and kinetics of gait between the two groups were compared.Immediately after inclusion,all subjects underwent full spinal X-ray measurements to compare the differences between the scoliosis and normal groups. RESULTS AND CONCLUSION:(1)Patients with scoliosis exhibited reduced relative rotational range of motion between the shoulder and trunk,as well as between the thorax and pelvis,compared to the normal group(P<0.05).However,the rotational range of motion in the pelvis was larger in patients with scoliosis compared to the normal group(P<0.05).(2)Patients with scoliosis showed decreased range of motion in the hip and knee joints,as well as reduced peak torque in hip joint flexion and extension,and lower peak values of ground reaction forces in the concave and convex directions,in comparison to the normal group(P<0.05).(3)Patients with scoliosis demonstrated greater asymmetry indices in knee joint range of motion,relative rotational range of motion between the shoulder and trunk,and between the thorax and pelvis,when compared to the normal group(P<0.05).(4)These findings illustrate a rigid movement pattern among the shoulder,thorax,and pelvis in patients with scoliosis during level walking.There is a reduction in range of motion in the hip and knee joints,as well as decreased peak torque values in hip joint flexion and extension,and ground reaction forces in the concave and convex directions.These characteristics can serve as foundational elements for assessing rehabilitation and developing treatment plans.

BACKGROUND:It has also been confirmed that ferroptosis is closely related to a variety of musculoskeletal diseases,such as rheumatoid arthritis,osteosarcoma,and osteoporosis.The pathophysiological mechanisms of ferroptosis and osteoporosis need to be further studied and elucidated to broaden our understanding of iron metabolism and osteoporosis.It will provide research ideas for the future elucidation of new mechanisms of osteoporosis and the development of new technologies and drugs for the treatment of osteoporosis. OBJECTIVE:To provide an overview of the current status of research on ferroptosis in osteoporosis,to provide a new direction for future research on the specific molecular mechanisms of osteoporosis,and to provide more effective and better options for osteoporosis treatment strategies. METHODS:The first author used the computer to search the literature published from 2000 to 2024 in CNKI,WanFang,VIP,and PubMed databases with search terms"ferroptosis,iron metabolism,osteoporosis,osteoblast,osteoclast,bone metabolism,signal pathway,musculoskeletal,review"in Chinese and English.A total of 68 articles were finally included according to the selection criteria. RESULTS AND CONCLUSION:(1)Ferroptosis is a new type of cell death discovered in recent years,which is usually accompanied by a large amount of iron accumulation and lipid peroxidation during cell death,and its occurrence is iron-dependent.This is distinctly different from several types of cell death that are currently being hotly studied(e.g.,cellular pyroptosis,necrotic apoptosis,cuproptosis,and autophagy).(2)Intracellular iron homeostasis is manifested as a balance between iron uptake,export,utilization,and storage.The body's iron regulatory system includes systemic and intracellular regulation.The main factor of systemic regulation is hepcidin produced by hepatic secretion,and cellular regulation depends on the iron regulatory protein/iron response element system.Of course,intracellular iron homeostasis can be controlled by other factors,such as hypoxia,cytokines,and hormones.(3)Lipid peroxidation causes oxidative damage to biological membranes(plasma membrane and internal organelle membranes),lipoproteins,and other lipid-containing molecules.Polyunsaturated fatty acid-containing phospholipids are important targets of lipid peroxidation.Free polyunsaturated fatty acid is an important substrate for lipid oxidation and can bind to the phospholipid bilayer,leading to over-oxidation and thus triggering lipid apoptosis.(4)Several studies have shown that osteoblasts are overloaded with iron in different ways,resulting in the accumulation of unstable ferrous iron and the generation of reactive oxygen species and lipid peroxides,causing ferroptosis of osteoblasts and ultimately a decrease in bone formation,affecting bone homeostasis and the development of osteoporosis.(5)Osteoclasts are large multinucleated cells formed by the fusion of mononuclear macrophage cell lines or bone marrow mesenchymal stem cells induced by nuclear factor-κB ligand receptor activator,and they have the function of bone resorption.Iron ions can promote osteoclast differentiation and bone resorption through the production of intracellular lipid reactive oxygen species,while iron chelators can inhibit osteoclast formation in vitro and thus affect the occurrence and development of osteoporosis.

BACKGROUND:It has been confirmed that the mixing of decellularized matrix and polymer electrospinning can not only improve the structural properties of fibers,but also preserve the biological decellularized of decellularized matrix.However,there is no relevant report on the preparation of skin tissue engineering scaffolds by electrospinning polyurethane and decellularized skin matrix. OBJECTIVE:To investigate the reparative effect of a decellularized skin matrix/polyurethane blended fibrous scaffold on rat skin defects. METHODS:Polyurethane electrospun fibrous scaffold and decellularized skin matrix/polyurethane blended fibrous scaffold were fabricated using the electrospinning technique.The fiber structure was observed under scanning electron microscope.Rat adipose mesenchymal stem cells were inoculated on two kinds of scaffolds respectively.The morphology of the scaffolds was observed under scanning electron microscope.Three full-thickness skin defects of 1 cm×1 cm were fabricated on the back of 10 SD rats.Polyurethane electrospun fibrous scaffolds(control group)and decellularized skin matrix/polyurethane blended fibrous scaffolds(experimental group)were implanted in two of the defects,and no material was implanted in the remaining defects(blank control group).The skin wound healing was observed at 1,2,and 3 weeks after operation.At 3 weeks after implantation,the wound was stained with hematoxylin and eosin and the scar area was calculated. RESULTS AND CONCLUSION:(1)Under scanning electron microscope,the two kinds of electrospun fibers were reticulated,and the rat adipose mesenchymal stem cells attached to the fibers on the two kinds of scaffolds,and the adhesion was good.(2)With the extension of the postoperative time,the skin wounds of each group gradually healed.By week 3 after the operation,the skin wounds of the experimental group and the control group were basically healed,and small ulcers could be seen on the wounds of the blank control group.Hematoxylin-eosin staining of skin wounds showed that the epidermal coverage of the wound was basically complete in the control group and the experimental group,and fibroblast growth and inflammatory cell infiltration could be seen in the dermis.In addition,the collagen fibers of the wound in the experimental group were abundant and arranged in a regular order,basically parallel to the epidermal surface.The wound epidermis of blank control group was still defective.The scar area of the experimental group was smaller than that of the other two groups(P<0.05,P<0.01).(3)These results indicate that the decellularized skin matrix/polyurethane blended fibrous scaffold can effectively repair full-thickness skin defects and improve scar formation in rats.