BACKGROUND:The extracellular-regulated protein kinase 5(ERK5)signaling protein is essential for the survival of organisms,and resveratrol can promote osteoblast proliferation through various pathways.However,whether resveratrol can regulate osteoblast function through the ERK5 signaling protein needs further verification. OBJECTIVE:To explore the regulatory effect of ERK5 on the proliferation of MC3T3-E1 cells and related secreted proteins,and to further verify whether resveratrol can complete the above process by activating ERK5. METHODS:Mouse MC3T3-E1 preosteoblasts were treated with complete culture medium,XMD8-92(an ERK5 inhibitor),epidermal growth factor(an ERK5 activator),resveratrol alone,XMD8-92+EGF,and resveratrol+XMD8-92,respectively.Western blot assay was used to detect the expression of ERK5 and p-ERK5 proteins,proliferation-related proteins Cyclin D1,CDK4 and PCNA,and osteoblast-secreted proteins osteoprotegerin and receptor activator of nuclear factor-κB ligand in MC3T3-E1 cells of each group.The fluorescence intensity of ERK5,osteoprotegerin and receptor activator of nuclear factor-κB ligand in each group was detected by cell immunofluorescence staining,and cell proliferation was detected by EdU staining,respectively.The appropriate concentration and time of resveratrol intervention in MC3T3-E1 cells were determined by cell morphology observation and cell counting kit-8 assay. RESULTS AND CONCLUSION:The activation of ERK5 signaling protein could effectively promote the proliferation of MC3T3-E1 cells,up-regulate the osteoprotegerin/receptor activator of nuclear factor-κB ligand ratio.The appropriate concentration and time for resveratrol intervention in MC3T3-E1 cells was 5 μmol/L and 24 hours,respectively.Resveratrol could activate ERK5 signaling protein,thereby promoting osteoblast proliferation and up-regulating the osteoprotegerin/RANKL ratio.All these results indicate that resveratrol can promote the proliferation of MC3T3-E1 cells and up-regulate the osteoprotegerin/RANKL ratio by activating the ERK5 signaling protein.

BACKGROUND:The absence of blood vessels in tendon tissue makes tendon repair challenging.Therefore,improving tendon healing and raising the efficacy of stem cell and other therapeutic cell transplantation after tendon damage have become hotspots for research in both clinical and scientific contexts. OBJECTIVE:The stem cells and gelatin microcarrier scaffold were joined to form tissue engineered stem cells.Human umbilical cord mesenchymal stem cells cultured in gelatin microcarriers were used to investigate the therapeutic impact and mode of action on tendinopathy healing in rats in vitro and In vivo. METHODS:(1)In vitro cell experiments:After seeding human umbilical cord mesenchymal stem cells with three-dimensional gelatin microcarriers,the cell vitality and survival were assessed.Human umbilical cord mesenchymal stem cells conventionally cultured were cultured as controls.(2)In vivo experiment:Adult SD rats were randomly assigned to normal group,tendinopathy group,2D group(tendinopathy+conventional culture of human umbilical cord mesenchymal stem cells),and 3D group(tendinopathy+gelatin microcarrier three-dimensional culture of human umbilical cord mesenchymal stem cells),with 6 rats in each group.Four weeks after therapy,animal behavior tests and histopathologic morphology of the Achilles tendon was examined. RESULTS AND CONCLUSION:(1)In vitro cell experiments:the seeded human umbilical cord mesenchymal stem cells on gelatin microcarriers showed high viability and as time went on,the stem cell proliferation level grew.Compared with the control group,3D stem cell culture preserved cell viability.(2)In vivo experiment:Following a 4-week treatment,the 3D stem cell culture group showed a significant improvement in both functional recovery of the lower limbs and histopathological scores when compared to the tendinopathy group.The 2D stem cell culture group also showed improvement in tendinopathy injury,but its effect is not as much as the 3D stem cell culture group.(3)The outcomes demonstrate that human umbilical cord mesenchymal stem cells cultured with three-dimensional gelatin microcarrier can promote the repair and regeneration of tendon injury tissue,and the repair effect is better than that of conventional human umbilical cord mesenchymal stem cells.

BACKGROUND:Endometrial receptivity is a key factor in embryo implantation in northwest Tibetan cashmere goats,and the expression of genes related to endometrial receptivity and their variable splicing are still unclear. OBJECTIVE:To analyze and explore genes and variable splicing events related to endometrial receptivity in northwest Tibetan cashmere goats. METHODS:On days 5 and 15 of pregnancy(representing pre receptive endometrium group and receptive endometrium group),three northwest Tibetan cashmere goats were randomly selected.Endometrial tissue was collected and stained with hematoxylin and eosin to observe tissue morphology.Immunohistochemical staining was used to detect the expression of endometrial receptive marker proteins leukemia inhibitory factor and vascular endothelial growth factor.After the total RNA was extracted and the quality test was qualified,transcriptome sequencing was performed to search differentially expressed mRNAs,lncRNAs,circRNAs,and miRNAs,perform functional prediction,and analyze alternative splicing mRNAs and lncRNAs related to endometrial receptivity. RESULTS AND CONCLUSION:(1)Compared with the pre receptive endometrium group,the expression levels of leukemia inhibitory factor and vascular endothelial growth factor proteins in the endometrial tissue of the receptive endometrium group were significantly increased.(2)The sequencing results showed that the differentially expressed genes were mostly mRNA and lncRNA genes,including 250 upregulated mRNAs,193 upregulated lncRNAs,135 downregulated mRNAs,and 123 downregulated lncRNAs,which were significantly enriched in the Wnt,Hedgehog,and Hippo signaling pathways.(3)Alternative splicing event analysis uncovered 8 differentially expressed variable splicing transcripts,which were all mRNA transcripts,including 2 downregulated and 6 upregulated,and were significantly associated with vascular endothelial growth factor receptor signaling,cell motility,and embryonic development.

BACKGROUND:Various proteins,signaling pathways,and inflammatory mediators are involved in the pathophysiological process of osteoarthritis.The development of small molecule drugs targeting these proteins,signaling pathways,and inflammatory mediators can effectively delay the progression of osteoarthritis and ameliorate its clinical manifestations. OBJECTIVE:To review the research progress of small molecule drugs in the treatment of osteoarthritis based on the pathogenesis of osteoarthritis. METHODS:PubMed,CNKI,and WanFang databases were searched with English search terms"osteoarthritis,arthritis,osteoarthrosis,degenerative,arthritides,deformans,small molecule drugs,small molecule inhibitors,small molecule agents"and Chinese search terms"osteoarthritis,small molecule drugs,small molecule inhibitors."A total of 68 articles were included for review according to the inclusion and exclusion criteria. RESULTS AND CONCLUSION:(1)Currently,studies concerning the pathogenesis of osteoarthritis remain unclear.The occurrence and development of osteoarthritis are strongly associated with proteins,cytokines,and signal transduction pathways,so its therapeutic mechanism is relatively complex.Currently,targeting proteins,cytokines,and signal transduction pathways related to osteoarthritis with small molecule drugs has become a major research focus.(2)Small molecule drugs frequently possess visible intracellular or extracellular targets and efficacy,containing enhancing cartilage repair,resisting joint degradation,attenuating inflammation,and relieving pain.Other anti-osteoarthritis small molecule drugs have shown promise in promoting stem cell chondrogenic differentiation and cartilage matrix reconstruction.(3)At present,small molecule drugs targeting the pathophysiological process of osteoarthritis to delay the progression of osteoarthritis are still in the experimental stage,but most of these small molecule drugs have shown the expected results in the experimental process,and there are no relevant studies to illustrate the efficacy of small molecule drugs in the treatment of osteoarthritis.(4)Small molecule drugs for the treatment of osteoarthritis have reached the expected experimental results in the basic experimental stage.Numerous studies have exhibited that small molecule drugs can target the suppression of specific proteins,cytokines,and signal transduction pathways that cause osteoarthritis,so as to treat osteoarthritis.Nevertheless,its safety and effectiveness still need to be identified by further basic and clinical studies.This process needs to be investigated and studied by more scholars.(5)At present,many scholars in and outside China have made contributions to the treatment of osteoarthritis.Compared with traditional treatment methods,small molecule drugs reveal better efficacy and safety in the basic experimental stage,and it is expected to become an emerging method for the treatment of osteoarthritis in the future to rid patients of pain.

BACKGROUND:Socket-shield technique can effectively maintain labial soft and hard tissues,but the incidence of postoperative complications such as exposure and displacement of root shield is relatively high.It is speculated that the root shield may be exposed and displaced due to excessive load after long-term function of dental implants. OBJECTIVE:Through three-dimensional finite element analysis,we aim to study the influence of varying root shield thicknesses on the stress distribution,equivalent stress peaks,and displacement in the root shield,periodontal ligaments,implant,and surrounding alveolar bone under normal occlusal loading.We also attempt to analyze the correlation between the thickness of the root shield and occurrence of mechanical events such as root shield exposure,displacement,and fracture. METHODS:Cone-beam CT data of a patient who met the indication standard of socket-shield technique for maxillary central incisor were retrieved from database.Reverse engineering techniques were used to build models of the maxillary bone and root shield,while forward engineering was used to create models for the implant components based on their parameters.Models depicting various root shield thicknesses(0.5,1.0,1.5,and 2.0 mm)were created using Solidworks 2022 software.ANSYS Workbench 2021 software was then used to simulate and analyze the effects of varying root shield thicknesses on stress distribution,equivalent stress peaks,and displacement of the root shields,periodontal ligaments,implants,and surrounding alveolar bone under normal occlusion. RESULTS AND CONCLUSION:(1)In all root shield models,the stress was concentrated on the palatal cervical side,both sides of the edges and the lower edge of the labial side.As the thickness of the root shield increased,the equivalent stress peak and displacement showed a decreasing trend.The 0.5 mm thickness model produced a stress concentration of 176.20 MPa,which exceeded the yield strength(150 MPa)of tooth tissue.(2)The periodontal ligament stress in each group was concentrated in the neck margin and upper region.With the increase of root shield thickness,the equivalent stress peak and displacement of periodontal ligament showed a decreasing trend.(3)Implant stress in all models was concentrated in the neck of the implant and the joint of the implant-repair abutment,and the labial side was more concentrated than the palatal side.With the increase of root shield thickness,the equivalent stress peak of the implant in the model showed an increasing trend.(4)In each group of models,stress of cortical bone concentrated around the neck of the implant and the periphery of the root shield,and the labial side was more concentrated than the palatal side.With the increase of the thickness of the root shield,the equivalent stress peak around the root shield decreased;the peak value of the equivalent stress of the bone around the neck of the implant showed an increasing trend.In the model,the stress of cancellous bone was mainly concentrated around the neck of the lip of the implant,the top of the thread,the root tip and the lower margin of the root shield,and the labial side was more concentrated than the palatal side.With the increase of the thickness of the root shield,the peak value of the equivalent stress of the bone around the root shield in the model showed a decreasing trend.The minimum principal stress of cortical bone in each group of models was concentrated around the neck of the implant,exhibiting a fan-shaped distribution.As the thickness of the root shield increased,the minimum principal stress of cortical bone showed an increasing trend.(5)These results indicate that different thicknesses of the root shield have different biomechanical effects.The root shield with a thickness of 0.5 mm is easy to fracture.For patients with sufficient bone width,the root shield with a thickness of 2.0 mm is an option to reduce the risk of complications such as root shield exposure,fracture,and displacement.Meanwhile,it should be taken into account to protect the periodontal ligament in the preparation process,and rounding treatments ought to be carried out on both sides and the lower edge of the root shield.

BACKGROUND:The imbalance between bone resorption and bone formation in microgravity environments leads to significant bone loss in astronauts.Current research indicates that bone loss under microgravity conditions is the result of the combined effects of various cells,tissues,and systems. OBJECTIVE:To review different biological effects of microgravity on various cells,tissues,or systems,and summarize the mechanisms by which microgravity leads to the development of osteoporosis. METHODS:Databases such as PubMed,Web of Science,and the Cochrane Database were searched for relevant literature from 2000 to 2023.The inclusion criteria were all articles related to tissue engineering studies and basic research on osteoporosis caused by microgravity.Ultimately,85 articles were included for review. RESULTS AND CONCLUSION:(1)In microgravity environment,bone marrow mesenchymal stem cells tend to differentiate more into adipocytes rather than osteoblasts,and hematopoietic stem cells in this environment are more inclined to differentiate into osteoclasts,reducing differentiation into the erythroid lineage.At the same time,microgravity inhibits the proliferation and differentiation of osteoblasts,promotes apoptosis of osteoblasts,alters cell morphology,and reduces the mineralization capacity of osteoblasts.Microgravity significantly increases the number and activity of osteoclasts.Microgravity also hinders the differentiation of osteoblasts into osteocytes and promotes the apoptosis of osteocytes.(2)In a microgravity environment,the body experiences changes such as skeletal muscle atrophy,microvascular remodeling,bone microcirculation disorders,and endocrine disruption.These changes lead to mechanical unloading in the bone microenvironment,insufficient blood perfusion,and calcium cycle disorders,which significantly impact the development of osteoporosis.(3)At present,the mechanism by which microgravity causes osteoporosis is relatively complex.A deeper study of these physiological mechanisms is crucial to ensuring the health of astronauts during long-term space missions,and provides a theoretical basis for the prevention and treatment of osteoporosis.

Objective: To explore the plasma metabonomic characteristics of patients with type 2 diabetes mellitus and turbid toxin accumulation syndrome. Methods: One hundred and three patients with type 2 diabetes mellitus and turbid toxin accumulation syndrome were enrolled from November 2023 to February 2024 in the First Teaching Hospital of Tianjin University of Traditional Chinese Medicine and 54 healthy individuals were recruited. The general data of the two groups were analyzed, and the plasma metabolite content was detected using ultra-high performance liquid chromatography-Orbitrap mass spectrometry. Construct an orthogonal partial least squares discriminant analysis model to screen metabolites with significant intergroup changes. The variable importance in projection≥ 1, |log2FC|>1, and P<0.05 were used as the criteria for the screening of differential metabolites. Annotate differential metabolites using internal databases and the human metabolome database, and perform pathway analysis using MetaboAnalyst website. Results: There was no statistically significant difference in gender and age between the two groups.Seventeen potential differential metabolites were identified. The D-4′-phosphopantothenate, 2, 6-dichloroindophenol, 4-methylphenol, hypoxanthine, 11, 12-epoxyeicosatrienoic acids, oleamide, 3-phenyllactic acid contents were higher in patients with type 2 diabetes mellitus and turbid toxin accumulation syndrome than in healthy individuals(P<0.05); 3-anisic acid, 3-iodo-octadecanoic acid, mebendazole, β-alanine, citric acid, trans-aconitic acid, geranyl diphosphate, lysophosphatidylcholine(18∶2), phosphatidylethanolamine(18∶1), and caprolactam contents were lower in patients with type 2 diabetes mellitus and turbid toxin accumulation syndrome than in healthy individuals(P<0.05). Ten metabolic pathways were identified, including the key metabolic pantothenate and coenzyme A biosynthesis pathways. Conclusion Metabolic differences were observed between patients with type 2 diabetes mellitus and turbid toxin accumulation syndrome and healthy individuals, and the underlying mechanism may involve the pantothenate and coenzyme A biosynthesis pathways, jointly mediated by D-4′-phosphopantothenate and β-alanine.

Pancreaticobiliary maljunction （PBM） is a rare congenital developmental defect of the biliary-pancreatic system characterized by a junction of the pancreatic and bile ducts outside the duodenal wall， forming an extended common channel. This anatomical anomaly compromises the normal function of Oddi’s sphincter， weakens defenses against reflux， and thus triggers a series of biliary and pancreatic complications. Although there is a relatively low incidence rate of PBM， its insidious clinical symptoms often lead to delayed diagnosis， which increases the difficulties in treatment and the risk of poor prognosis. For PBM patients with marked bile duct dilatation， surgical intervention， especially cholecystectomy combined with extrahepatic bile duct resection and bile duct-jejunum Roux-en-Y anastomosis， remains the standard treatment at present. For PBM without marked bile duct dilatation， there are still controversies over related treatment strategies， and most experts are in favor of cholecystectomy， while there is still a lack of consensus on the management of extrahepatic bile ducts， which requires further research and exploration. Endoscopic retrograde cholangiopancreatography （ERCP） is currently the gold standard for diagnosing PBM and assessing pancreaticobiliary abnormalities， and it can not only clarify the nature of lesion， but also collect the bile and biliary duct tissue for pathological examination. ERCP also has the function of interventional treatment， such as stenting， expansion， and drainage， thereby bringing benefits to patients comorbid with biliary neoplasms. However， the application of ERCP in screening is limited by its invasiveness， with increases in technique complexity and the risk of complications in the pediatric population. This article summarizes the definition， classification， pathogenesis， and epidemiological features of PBM and the research advances in current diagnosis and treatment strategies， in order to provide guidance for clinical practice.

The pathological changes of myocardial infarction （MI） are mainly characterized by progressive myocardial ischemic necrosis， decline in cardiac diastolic function， thinning of the ventricular wall， and enlargement of the ventricles. The clinical manifestations include myocardial ischemia， heart failure， arrhythmia， shock， and even sudden cardiac death， rendering MI one of the most perilous cardiovascular diseases. Currently， the clinical treatment for MI primarily involves interventional procedures and drug therapy. However， due to their significant side effects and high complication rates associated with these treatments， they fail to ensure a satisfactory quality of life and long-term prognosis for patients. On the other hand， traditional Chinese medicine has demonstrated remarkable potential in improving patient prognosis while reducing side effects. Research has elucidated that various signaling pathways such as nuclear transcription factor-κB （NF-κB）， adenosine 5̒-monophosphate-activated protein kinase （AMPK）， transforming growth factor-β （TGF-β）/Smads， mitogen-activated protein kinase （MAPK）， Wnt/β-catenin （β-catenin）， and phosphatidylinositol 3-kinase （PI3K）/protein kinase B（Akt） play crucial roles in regulating the occurrence and development of MI. Effectively modulating these signaling pathways through its therapeutic interventions， traditional Chinese medicine can enhance MI management by inhibiting apoptosis， providing anti-inflammatory properties， alleviating oxidative stress levels， and resisting myocardial ischemia. Due to its notable efficacy and favorable safety， it has become an area of focus in clinical practice.

ObjectivePhotoacoustic pump-probe imaging can effectively eliminate the interference of blood background signal in traditional photoacoustic imaging, and realize the imaging of weak phosphorescence molecules and their triplet lifetimes in deep tissues. However, background differential noise in photoacoustic pump-probe imaging often leads to large fitting results of phosphorescent molecule concentration and triplet lifetime. Therefore, this paper proposes a novel triplet lifetime fitting method for photoacoustic pump-probe imaging. By extracting the phase of the triplet differential signal and the background noise, the fitting bias caused by the background noise can be effectively corrected. MethodsThe advantages and feasibility of the proposed algorithm are verified by numerical simulation, phantom and in vivo experiments, respectively. ResultsIn the numerical simulation, under the condition of noise intensity being 10% of the signal amplitude, the new method can optimize the fitting deviation from 48.5% to about 5%, and has a higher exclusion coefficient (0.88>0.79), which greatly improves the fitting accuracy. The high specificity imaging ability of photoacoustic pump imaging for phosphorescent molecules has been demonstrated by phantom experiments. In vivo experiments have verified the feasibility of the new fitting method proposed in this paper for fitting phosphoometric lifetime to monitor oxygen partial pressure content during photodynamic therapy of tumors in nude mice. ConclusionThis work will play an important role in promoting the application of photoacoustic pump-probe imaging in biomedicine.