BACKGROUND:Studies have shown that metformin has anti-inflammatory,anti-tumor,anti-aging and vasoprotective effects,and can inhibit the progression of osteoarthritis,but its specific mechanism of action remains unclear. OBJECTIVE:To investigate the mechanism of metformin on cartilage protection in a rat model of osteoarthritis. METHODS:Forty male Sprague-Dawley rats were randomly divided into four groups(n=10 per group):blank,control,sham-operated,and metformin groups.The blank group did not undergo any surgery.In the sham-operated group,the joint cavity was exposed.In the model group and the metformin group,the modified Hulth method was used to establish the osteoarthritis model.At 1 day after modeling,the rats in the metformin group were given 200 mg/kg/d metformin by gavage,and the model,blank,and sham-operated groups were given normal saline by gavage.Administration in each group was given for 4 weeks consecutively.Hematoxylin-eosin staining,toluidine blue staining,and safranin O-fast green staining were used to observe the morphological structure of rat knee joints.Immunohistochemical staining and western blot were used to detect the protein expression of SOX9,type Ⅱ collagen,a disintegrin and metalloproteinase with thrombospondin motifs 5(ADAMTS5),Beclin1,P62,phosphatidylinositol 3-kinase(PI3K),p-PI3K,protein kinase B(AKT),p-AKT,mammalian target of rapamycin(Mtor),and p-Mtor in rat cartilage tissue. RESULTS AND CONCLUSION:The results of hematoxylin-eosin,toluidine blue and safranin O-fast green staining showed smooth cartilage surface of the knee joints and normal histomorphology in the blank group and the sham-operated group,while in the model group,there was irregular cartilage surface of the knee joint and cartilage damage,with a decrease in the number of chondrocytes and the content of proteoglycans in the cartilage matrix.In the metformin group,there was a significant improvement in the damage to the structure of the cartilage in the knee joints of the rats,and the cartilage surface tended to be smooth,with an increase in the number of chondrocytes and the content of proteoglycans in the cartilage matrix.Immunohistochemistry staining and western blot results showed that compared with the control and sham-operated groups,the expression of SOX9,type Ⅱ collagen,and Beclin1 proteins in the cartilage tissue of rats in the model group was significantly decreased(P<0.05).Conversely,the expression of ADAMTS5,P62,as well as p-PI3K,p-AKT,and p-Mtor proteins was significantly increased(P<0.05).Furthermore,compared with the model group,the expression of SOX9,type Ⅱ collagen,and Beclin1 proteins in the cartilage tissue of rats in the metformin group was significantly increased(P<0.05),while the expression of ADAMTS5,P62,as well as p-PI3K,p-AKT,and p-Mtor proteins was significantly decreased(P<0.05).To conclude,Metformin can improve the autophagy activity of chondrocytes and reduce the degradation of cartilage matrix in osteoarthritis rats by inhibiting the activation of PI3K/AKT/Mtor signaling pathway,thus exerting a protective effect on articular cartilage.

BACKGROUND:Transcranial magneto-acoustic-electrical stimulation is a novel non-invasive neural regulation technique that utilizes the induced electric field generated by the coupling effect of ultrasound and static magnetic field to regulate the discharge activity of the nervous system.However,the mechanism by which it affects synaptic plasticity in the brain is still not enough. OBJECTIVE:To explore the effect of transcranial magneto-acoustic-electrical stimulation intensity on synaptic plasticity of the prefrontal cortex neural network in mice. METHODS:(1)Animal experiment:Twenty-four C57 mice were equally and randomly divided into four groups:the control group receiving pseudo-stimulation,the 6.35 W/cm2 stimulation group receiving coupled stimulation of 0.3 T,6.35 W/cm2,the 17.36 W/cm2 stimulation group receiving coupled stimulation of 0.3 T,17.36 W/cm2,and the 56.25 W/cm2 stimulation group receiving coupled stimulation of 0.3 T,56.25 W/cm2.The local field potential signals and behavioral correctness were recorded during the execution of T-maze in mice.(2)Modeling and simulation experiments:A neural network model of the prefrontal cortex in mice stimulated by transcranial magneto-acoustic-electrical stimulation was constructed to compare the structural connectivity characteristics of the neural network under different stimulation intensities. RESULTS AND CONCLUSION:Transcranial magneto-acoustic-electrical stimulation could effectively shorten the behavior learning time,improve the working memory ability of mice(P＜0.05),and continue to stimulate the frontal lobe of mice after learning behavior.There was no significant difference in the accuracy of the T-maze behavioral experiment among the experimental groups(P＞0.1).Analysis of local field potential signals in the frontal lobe of mice revealed that transcranial magneto-acoustic-electrical stimulation promoted energy enhancement of β and γ rhythms.As the stimulation intensity increased,there was an asynchronous decrease in β and γ rhythms.Through β-γ phase amplitude coupling,it was found that stimuli could enhance the neural network's ability to adapt to new information and task requirements.Modeling and simulation experiments found that stimulation could enhance the discharge level of the neural network,increase the long-term synaptic weight level,and decrease the short-term synaptic weight level only when the stimulation intensity was high.To conclude,there is a complex nonlinear relationship between different stimulus intensities and the functional structure of neural networks.This neural regulation technique may provide new possibilities for the treatment of related neurological diseases such as synaptic dysfunction and neural network abnormalities.

BACKGROUND:Previous studies have confirmed that Wen-Shen-Tong-Du Decoction can promote the recovery of spinal cord injury by inhibiting pyroptosis of splenic B cells,promoting the phagocytosis of myelin debris by microvascular endothelial cells,affecting the migration and infiltration of microglia,promoting the recovery of damaged neurons,and decreasing neuronal apoptosis after spinal cord injury,but the mechanism of this is still not clear. OBJECTIVE:To investigate the effect of Wen-Shen-Tong-Du Decoction on the triggering receptor expressed on myeloid cells 2(TREM2)and PI3K/Akt signaling pathways in mice following spinal cord injury. METHODS:Thirty-six C57BL/6 mice were selected and randomly divided into a sham-operation group,a model group and a Wen-Shen-Tong-Du Decoction group,with 12 mice in each group.In the model and Wen-Shen-Tong-Du Decoction groups,mouse models of T10 spinal cord injury were prepared by the modified Allen's method.On the 1st day after modeling,the Wen-Shen-Tong-Du Decoction group was given Wen-Shen-Tong-Du Decoction by gavage,and the sham-operation group and the model group were given saline by gavage once a day for 28 days.During the drug administration period,mouse motor function was evaluated by Basso Mouse Scale score and inclined plane test.On the 7th and 28th days after modeling,hematoxylin-eosin staining was used to observe the histopathological changes in the spinal cord tissue of the mice;immunofluorescence double staining was used to detect the protein expression of ionized calcium binding adaptor molecule 1(IBA1)and TREM2;and western blot assay was used to detect the expression of TREM2,PI3K,p-PI3K,Akt,p-Akt,Bcl2,Bax and Caspase3 in spinal cord tissue. RESULTS AND CONCLUSION:Basso Mouse Scale scores and inclined plane test results indicated that the motor function of the mouse hindlimbs was declined after spinal cord injury,and Wen-Shen-Tong-Du Decoction significantly improved motor function in mice with spinal cord injury.Hematoxylin-eosin staining results revealed that Wen-Shen-Tong-Du Decoction significantly ameliorated the pathological structure of spinal cord tissue compared with the model group,manifesting as reduced degrees of dorsal white matter and neuronal atrophy,decreased cytoplasmic vacuolization,and reduced inflammatory cell infiltration.Immunofluorescence double staining results showed that on the 7th day after modeling,the protein expression of IBA1 and TREM2 in the model group was lower than that in the sham-operation group(P＜0.05),and the protein expression of IBA1 and TREM2 in the Wen-Shen-Tong-Du Decoction group was higher than that in the model group(P＜0.05);on the 28th day after modeling,the protein expression of TREM2 in the model group was lower than that in the sham-operation group(P＜0.05),and the protein expression of TREM2 in the spinal cord tissue of the mice in the Wen-Shen-Tong-Du Decoction group was higher than that in the model group(P＜0.05).Western blot results analysis demonstrated that on the 7th day after modeling,compared with the sham-operation group,the model group exhibited a significant reduction in TREM2,PI3K,and Bcl2/Bax(P＜0.05),as well as a significant increase in p-Akt,Bax and p-Akt/Aktp-PI3K(P＜0.05);compared with the model group,the Wen-Shen-Tong-Du Decoction group showed a significant increase in TREM2,PI3K,p-PI3K,Akt,p-Akt,Bcl2,p-PI3K/PI3K,p-Akt/Ak,and Bcl2/Bax(P＜0.05),as well as a significant decrease in Bax and Caspase3 protein expression(P＜0.05).On the 28th day after modeling,compared with the sham-operation group,the model group exhibited a significant reduction in TREM2,PI3K,p-PI3K,Akt,p-Akt,Bcl2 and Bcl2/Bax(P＜0.05),as well as a significant increase in Bax protein expression(P＜0.05);compared with the model group,the Wen-Shen-Tong-Du Decoction group showed a significant increase in TREM2,PI3K,Akt,p-Akt,Bcl2,and Bcl2/Bax(P＜0.05),as well as a significant decrease in Bax protein expression(P＜0.05).To conclude,Wen-Shen-Tong-Du Decoction may activate the PI3K/Akt signaling pathway by up-regulating the expression of TREM2 protein in microglia,and then inhibit neuronal apoptosis,thus exerting neuroprotective effects and promoting the repair of spinal cord injury.

BACKGROUND:Impaired hamstring muscle strength,anterior patellar pain,high incidence of osteoarthritis,and loss of proprioception after anterior cruciate ligament reconstruction lead to poor functional recovery due to a higher incidence of osteoarthritis and loss of proprioception.Arthroscopic repair of the anterior cruciate ligament combined with dynamic or static internal brace repair preserves the original ligament structure and results in favorable short-term outcomes. OBJECTIVE:To prospectively observe the efficacy and imaging findings of modified double-bundle arthroscopic repair of the anterior cruciate ligament after Sherman type Ⅰ injury METHODS:From January 2020 to September 2022,a total of 60 patients with anterior cruciate ligament injury admitted at the Department of Sports Medicine,Foshan Hospital of Traditional Chinese Medicine were included and divided into two groups(n=30 per group)according to the treatment protocols.The functional repair group was treated with double bundle repair combined with internal brace fixation,and the reconstruction group was treated with single bundle anatomical reconstruction of autologous hamstring muscle.All cases were followed up for 12 months after surgery,and International Knee Documentation Committee score,Lysholm score and KT-1000 difference between the affected and healthy sides of the two groups were evaluated at 3,6 and 12 months after surgery. RESULTS AND CONCLUSION:Three months after surgery,International Knee Documentation Committee scores,Lysholm scores and KT-1000 difference between the affected and healthy sides were significantly different between the two groups(P＜0.05),and the functional repair group was better than the reconstruction group.At 6 and 12 months after surgery,there was no significant difference in International Knee Documentation Committee score,Lysholm score and KT-1000 difference between the two groups(P＞0.05).To conclude,anterior cruciate ligament repair preserves the original ligament structure,avoids drilling larger marrow tracts and removing autologous tendons for reconstruction,reduces the damage to the original normal structure,and has fewer complications.Early postoperative efficacy is better than that of anterior cruciate ligament reconstruction with stumps,but there is no significant difference in the efficacy of the two groups 6 months after surgery.

BACKGROUND:Exercise as a form of active rehabilitation can improve the dysfunction caused by peripheral nerve injury,and different exercise modalities target different lesion sites and recovery mechanisms. OBJECTIVE:To comprehensively analyze the application and mechanisms of different exercise modalities in functional recovery from peripheral nerve injury. METHODS:A computerized search was conducted in PubMed and CNKI databases for relevant literature published before January 2024.The search terms used were"peripheral nerve injury,spinal cord,exercise,cerebral cortex,muscle atrophy,mirror therapy,blood flow restriction training"in both English and Chinese.Finally,77 articles were included for review. RESULTS AND CONCLUSION:Peripheral nerve injury can cause systemic pathological changes such as skeletal muscle atrophy,corresponding spinal cord segmental lesions,and sensorimotor cortex remodeling.Aerobic exercise can improve dysfunction by enhancing the immune response,promoting glial cell polarization,and promoting the release of nerve growth factor.Blood flow restriction exercise can regulate the secretion of muscle growth factor,promote muscle growth and enhance muscle strength.Mirror movement has a good effect in activating the cerebral cortex and reducing cortical remodeling.Different exercise modalities have potential benefits in functional recovery after peripheral nerve injury;however,there are still some problems and challenges,such as the choice of exercise modalities,the control of exercise intensity and frequency,and the detailed analysis of mechanisms.

BACKGROUND:Osteoporotic fracture is the most serious complication of osteoporosis.Previous studies have demonstrated that gut microbiota has a regulatory effect on skeletal tissue and that gut microbiota has an important relationship with osteoporotic fracture,but the causal relationship between the two is unclear. OBJECTIVE:To explore the causal relationship between gut microbiota and osteoporotic fractures using Mendelian randomization method. METHODS:The genome-wide association study(GWAS)datasets of gut microbiota and osteoporotic fracture were obtained from the IEU Open GWAS database and the Finnish database R9,respectively.Using gut microbiota as the exposure factor and osteoporotic fracture as the outcome variable,Mendelian randomization analyses with random-effects inverse variance weighted,MR-Egger regression,weighted median,simple model,and weighted model methods were performed to assess whether there is a causal relationship between gut microbiota and osteoporotic fracture.Sensitivity analyses were performed to test the reliability and robustness of the results.Reverse Mendelian randomization analyses were performed to further validate the causal relationship identified in the forward Mendelian randomization analyses. RESULTS AND CONCLUSION:The results of this Mendelian randomization analysis indicated a causal relationship between gut microbiota and osteoporotic fracture.Elevated abundance of Actinomycetales[odds ratio(OR)=1.562,95%confidence interval(CI):1.027-2.375,P=0.037),Actinomycetaceae(OR=1.561,95%CI:1.027-2.374,P=0.037),Actinomyces(OR=1.544,95%CI:1.130-2.110,P=0.006),Butyricicoccus(OR=1.781,95%CI:1.194-2.657,P=0.005),Coprococcus 2(OR=1.550,95%CI:1.068-2.251,P=0.021),Family ⅩⅢ UCG-001(OR=1.473,95%CI:1.001-2.168,P=0.049),Methanobrevibacter(OR=1.274,95%CI:1.001-1.621,P=0.049),and Roseburia(OR=1.429,95%CI:1.015-2.013,P=0.041)would increase the risk of osteoporotic fractures in patients.Elevated abundance of Bacteroidia(OR=0.660,95%CI:0.455-0.959,P=0.029),Bacteroidales(OR=0.660,95%CI:0.455-0.959,P=0.029),Christensenellacea(OR=0.725,95%CI:0.529-0.995,P=0.047),Ruminococcaceae(OR=0.643,95%CI:0.443-0.933,P=0.020),Enterorhabdus(OR=0.558,95%CI:0.395-0.788,P=0.001),Eubacterium rectale group(OR=0.631,95%CI:0.435-0.916,P=0.016),Lachnospiraceae UCG008(OR=0.738,95%CI:0.546-0.998,P=0.048),and Ruminiclostridium 9(OR=0.492,95%CI:0.324-0.746,P=0.001)would reduce the risk of osteoporotic fractures in patients.We identified 16 gut microbiota associated with osteoporotic fracture by the Mendelian randomization method.That is,using gut microbiota as the exposure factor and osteoporotic fracture as the outcome variable,eight gut microbiota showed positive causal associations with osteoporotic fracture and another eight gut microbiota showed negative causal associations with osteoporotic fracture.The results of this study not only identify new biomarkers for the early prediction of osteoporotic fracture and potential therapeutic targets in clinical practice,but also provide an experimental basis and theoretical basis for the study of improving the occurrence and prognosis of osteoporotic fracture through gut microbiota in bone tissue engineering.

BACKGROUND:Macrophage migration inhibitory factor(MIF)is a pleiotropic cytokine,which is secreted in different types of stem cells and can regulate the proliferation,differentiation and migration of various types of stem cells.Our previous research has confirmed that human embryonic stem cells secrete MIF and that its concentration in the culture medium is relatively stable.However,whether MIF is involved in the survival,proliferation and differentiation of human embryonic stem cells remains unclear. OBJECTIVE:To investigate the effects of MIF on survival,proliferation,and differentiation of human embryonic stem cells. METHODS:(1)Human embryonic stem cells H9 were cultured.The growth curve of cells was detected and plotted by CCK-8 assay.Enzyme-linked immunosorbent assay was used to determine the level of MIF in the medium.(2)To determine the effects of exogenous MIF on the survival and proliferation of human embryonic stem cells,different groups were established:the control group,which was cultured in stem cell medium without any modifications;the exogenous MIF group,which was treated with different concentrations(30,100,300 ng/mL)of MIF in the stem cell medium;the MIF inhibitor ISO-1 group,which was treated with different concentrations(2,7,21 μmol/L)of ISO-1 in the stem cell medium;and the MIF+ISO-1 group,which was treated with different concentrations of ISO-1 along with 100 ng/mL of MIF.Cell viability was assessed using the CCK-8 assay.(3)To further elucidate the effect of MIF gene on survival and proliferation of human embryonic stem cell,the MIF knockout H9 cell line was constructed by CRISPR-Cas 9 technology to observe the lineage establishment.(4)To determine the effect of high concentrations of MIF on human embryonic stem cell differentiation,100 ng/mL MIF and 100 ng/mL of CXCR4 neutralizing antibody were separately added to the normal stem cell culture medium.The expression levels of self-renewal factors(KLF4,c-MYC,NANOG,OCT4,and SOX2)and differentiation transcription factors(FOXA2,OTX2)were measured using real-time quantitative polymerase chain reaction,immunofluorescence staining,and western blot analysis. RESULTS AND CONCLUSION:(1)The logarithmic growth phase of H9 cells was between 3-6 days.Under normal growth conditions,human embryonic stem cells secreted MIF at a concentration of approximately 20 ng/mL,independent of cell quantity.(2)Compared to the control group,the addition of different concentrations of MIF had no effect on the proliferation of human embryonic stem cells(P>0.05).ISO-1 significantly inhibited the proliferation of human embryonic stem cells,with a stronger inhibition observed at higher concentrations of ISO-1(P<0.05).The addition of MIF in the presence of ISO-1 reduced the inhibitory effect of ISO-1(P<0.05).(3)Real-time quantitative polymerase chain reaction showed that knocking out 50%of the MIF gene resulted in a significant decrease in the growth vitality of human embryonic stem cells and failure to establish cell lines.(4)Adding 100 ng/mL exogenous MIF to the culture medium resulted in a decrease in the mRNA,protein,and fluorescence expression levels of the self-renewal transcription factor KLF4,while the mRNA,protein,and fluorescence expression levels of the differentiation factor FOXA2 increased.(5)When 100 ng/mL CXCR4 neutralizing antibody was added to the culture medium,the mRNA and protein expression levels of KLF4 increased,while the mRNA and protein expression levels of FOXA2 decreased,contrary to the expression trend observed in the MIF group.In conclusion,the endogenous secretion of MIF by human embryonic stem cells is essential for their survival.The addition of MIF to the culture medium does not promote the proliferation of human embryonic stem cells.However,it can lead to a decrease in the expression of the self-renewal factor KLF4 and an increase in the expression of the transcription factor FOXA2.This provides a clue for further investigation into the effects and mechanisms of MIF on the differentiation of human embryonic stem cells.The MIF-CXCR4 axis plays a regulatory role in this process.

BACKGROUND:Research has demonstrated a close association between ferroptosis and vascular dementia.Tongmai Kaiqiao Pill has a certain effect on improving the cognitive function of vascular dementia patients,but its mechanism is unclear. OBJECTIVE:To explore the interventional effects and molecular mechanisms of Tongmai Kaiqiao Pill for vascular dementia based on the regulation of ferroptosis by the nuclear factor erythroid-2-related factor 2(Nrf2)/heme oxygenase-1(HO-1)/glutathione peroxidase 4(GPX4)signaling pathway. METHODS:Among eighty-four SD male rats,12 rats were used as the sham-operated group,and the rest of them were prepared as a model of vascular dementia by the modified 2-VO method,and then randomly divided into the model group,the Tongmai Kaiqiao Pills high-,moderate-,and low-dosage(27.6,13.8,and 6.9 g/kg)groups,the combined group(Tongmai Kaiqiao Pill high-dosage+ML385,20 mg/kg),and the donepezil hydrochloride group(0.45 mg/kg).The drug was given once a day by intragastric administration.The combined group was also intraperitoneally injected Nrf2 inhibitor ML385,once a day,for 4 weeks.Morris water maze was used to detect the learning memory ability of rats.Hematoxylin-eosin staining was used to observe the histopathological changes in the hippocampus of rats in each group.Colorimetric assay was used to detect the content of reduced glutathione,ferrous ion(Fe2+),and malondialdehyde in the serum of rats.Prussian blue staining was used to detect the iron deposition in the hippocampal tissue of rats.Transmission electron microscopy was used to observe the ultrastructural changes of mitochondria in rat hippocampal tissues.Western blot assay was used to detect the protein expression levels of Nrf2,HO-1,GPX4,XCT,and ferritin heavy chain 1(FTH1)in rat hippocampal tissues. RESULTS AND CONCLUSION:(1)In comparison to the sham operation,rats in the model group exhibited a significantly prolonged latency period(P<0.05)and a reduced number of platform crossings(P<0.05).Additionally,the hippocampal tissues of these rats displayed loosely organized structure,deeply stained cell nuclei,and solidified or lysed chromatin.Ferri ions aggregated in CA1 region.There were atrophied mitochondria with dissolved cristae and thickened mitochondrial membranes.Fe2+,malondialdehyde,and reduced glutathione levels in rat serum were found to be elevated(P<0.05).A significant reduction in the expression of GPX4,HO-1,XCT,Nrf2,and FTH1 proteins was detected in the hippocampus(P<0.05).(2)Compared to the model group,the average escape latency of the rats was significantly reduced following intervention with Tongmai Kaiqiao Pills and donepezil hydrochloride(P<0.05),with an increased number of platform crossings(P<0.05).Hippocampal neurons showed significant recovery.Notably,iron aggregation in the CA1 region was significantly reduced,and mitochondrial structure and function were improved.There were significant reductions in Fe2+and malondialdehyde levels,while the levels of GPX4,HO-1,XCT,Nrf2,and FTH1 in rat hippocampal tissues,and reduced glutathione in serum were significantly increased(P<0.05).(3)The high-dose Tongmai Kaiqiao Pills exhibited a treatment effect comparable to that of donepezil hydrochloride(P>0.05),with a significant prolongation of water maze escape latency(P<0.05),a reduced number of platform crossings(P<0.05),and insignificant neuronal pathological changes in the CA1 area.However,the combined group showed increased iron deposition,elevated malondialdehyde and Fe2+levels in blood serum(P<0.05),reduced glutathione content(P<0.05),hippocampal tissue mitochondrial atrophy,and reduced expression of Nrf2,XCT,HO-1,GPX4,and FTH1 proteins(P<0.05).Within a certain range,higher doses of Tongmai Kaiqiao Pills demonstrated a more pronounced effect,comparable to the efficacy of high-dose donepezil hydrochloride.(4)It is concluded that Tongmai Kaiqiao Pills have been shown to mitigate histopathological changes in the rat hippocampus and enhance cognitive function in rats with vascular dementia.The mechanism of action is likely associated with the suppression of ferroptosis through the activation of the Nrf2/HO-1/GPX4 signaling pathway.

BACKGROUND:As a common method of cancer treatment,chemotherapy has a certain therapeutic effect in the early stage.However,as the frequency of chemotherapy increases,the resistance of tumor cells to drugs gradually increases,that is,chemotherapy resistance.At present,the main mechanisms of chemotherapy resistance include the failure of chemotherapy drugs to reach the tumor site,the loss of drug activity leading to a decrease in drug efficacy,and tumor cells evading drug attack by reshaping their metabolic functions,gene phenotypes,and microenvironment.However,the specific mechanism remains to be discussed in depth. OBJECTIVE:To summarize the mechanisms by which exosomal miRNA is involved in drug resistance in different tumors,and to propose potential targets. METHODS:The PubMed database was searched using the English search terms"hematological malignancies,liver cancer,lung cancer,breast cancer,melanoma,colorectal cancer,drug resistance,exosomal miRNAs."The search time range was from January 2013 to August 2023.Preliminary screening was carried out by reading the titles and abstracts,and the exclusion criteria were for literature with poor relevance to the research content or repetitive content.Finally,60 articles were included for review. RESULTS AND CONCLUSION:(1)Exosomal miRNA enters the intercellular matrix and circulation,and participates in the formation and development of different tumor biological processes,including tumor microenvironment remodeling,angiogenesis,and drug resistance,by exerting local paracrine or distal effects.(2)Exosomal miRNA can penetrate the cell membrane into the cytoplasm of another cell,activate or inhibit the signaling pathway in the recipient cell by delivering miRNA,and maintain cell survival,proliferation,and metastasis during chemotherapy,thus leading to drug resistance.(3)Many exosomal miRNAs related to chemotherapy resistance have been identified and studied as common tumor treatment targets.(4)Although exosomal miRNA holds great promise as potential biomarkers and therapeutic targets,there are still some research deficiencies that need to be addressed:Firstly,there is a lack of standardized protocols for exosome isolation and characterization,resulting in differences in the methods used in different studies;secondly,although the presence and abundance of miRNAs in exosomes have been widely studied,their functional roles and mechanisms are not completely clear.Elucidating the specific targets and pathways regulated by exosomal can provide valuable insights into their biological significance and potential therapeutic applications.Addressing these research gaps will contribute to a more comprehensive understanding of exosomal miRNAs and their potential applications in various fields,including diagnosis,therapy,and personalized medicine.

BACKGROUND:The pathogenesis of diabetic peripheral neuropathy has not yet been clarified,and TAM(Tyro3,Axl,and MerTK)receptor tyrosine kinases can control apoptotic cells and suppress inflammatory responses in the central nervous system. OBJECTIVE:To investigate the difference of Mer receptor tyrosine kinase(MerTK)levels in plasma and sciatic nerve tissue of Sprague-Dawley rats with type 2 diabetes and diabetic peripheral neuropathy,and to study the correlation between MerTK and diabetic peripheral neuropathy. METHODS:Forty male Sprague-Dawley were randomly divided into control group with 15 rats,type 2 diabetes group with 10 rats,and diabetic peripheral neuropathy group with 15 rats.The control group was fed with ordinary diet,while the experimental groups were fed with high-fat and high-sugar diet.After 6 weeks,intraperitoneal injection of streptozotocin at the minimum dose of 35 mg/kg was administered in the two experimental groups.After 14 days,tail vein blood was collected to detect blood glucose.If blood glucose≥16.7 mmol/L,the model of type 2 diabetes was successfully established.Rats in the diabetic peripheral neuropathy group continued to be fed with a high-sugar and high-fat diet for 8 weeks.The sciatic nerve conduction velocity of rats was detected through live isolation under anesthesia.Blood samples were collected from the abdominal aorta,and the sciatic nerve tissue was collected.Histological changes of nerve fibers in each group were observed under a light microscope to confirm the success of diabetic peripheral neuropathy modeling.ELISA was used to detect peripheral blood glucose,blood lipids and serum MerTK levels in rats;hematoxylin-eosin staining was used to observe the histological changes in the sciatic nerve;immunofluorescence,immunohistochemistry and western blot were used to detect the expression of MerTK in the sciatic nerve tissue. RESULTS AND CONCLUSION:The Sprague-Dawley rat models of type 2 diabetes and type 2 diabetes peripheral neuropathy were successfully constructed,and the modeling rate of diabetic peripheral neuropathy was 80%.Compared with the control group,the blood glucose levels of rats in the type 2 diabetes and diabetic peripheral neuropathy groups were significantly higher(P<0.000 1),while the blood glucose level in the diabetic peripheral neuropathy group was higher than that in the type 2 diabetes group;and the sciatic nerve conduction velocity was significantly decreased(P<0.05),which was lower in the diabetic peripheral neuropathy group than the type 2 diabetes group.Histological examination:Compared with the control group,the sciatic nerve nuclei were reduced in the type 2 diabetes group,with some vacuolar degeneration and phagocytosis;in the diabetic peripheral neuropathy group,the cell body was swollen,the nuclear spacing was increased,vacuolar degeneration was observed,and the myelin sheath was partitioned and unsmooth,and lattice-like axons appeared.Serum MerTK levels were significantly higher in the diabetic peripheral neuropathy group than the control group.Expression of MerTK in the sciatic nerve tissue was significantly upregulated in the diabetic peripheral neuropathy group compared with the control group(P<0.05).To conclude,elevated levels of MerTK in plasma and sciatic nerve tissue of rats with diabetic peripheral neuropathy are presumably related to its anti-inflammatory and immunomodulatory effects.