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 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.

BACKGROUND:Fluid shear stress plays an important role in osteoblast proliferation and apoptosis.However,whether Caveolin-1 is involved in the process of fluid shear stress-induced proliferation and apoptosis in osteoblasts is unknown. OBJECTIVE:To explore the role of Caveolin-1 in fluid shear stress-regulated osteoblast proliferation and apoptosis. METHODS:The MC3T3-E1 osteoblasts in good growth status were selected and loaded with fluid shear stress at an intensity of 1.2 Pa for different times(0,30,60,90 minutes).The expression of Caveolin-1 protein was observed and conditions with a time of 60 minutes were screened for the experiment.MC3T3-E1 cells were divided into control group,fluid shear stress group,fluid shear stress+pcDNA 3.1 group(control),fluid shear stress+pcDNA Cav-1 group(plasmid overexpression),and intervened with fluid shear stress and overexpression of Cav-1,respectively.The expression of molecules related to proliferation and apoptosis in MC3T3-E1 cells was detected by qRT-PCR and western blot.In addition,the proliferative activity of MC3T3-E1 cells was detected by cell counting kit-8 and EdU assay;and cell apoptosis was detected by Hoechst 33258 and flow cytometry. RESULTS AND CONCLUSION:The expression of Caveolin-1 in MC3T3-E1 cells was significantly down-regulated after loading fluid shear stress,and the expression level was lowest after 60 minutes.Overexpression of Caveolin-1 attenuated the proliferation-promoting and apoptosis-suppressing effects of fluid shear stress in MC3T3-E1 cells.In conclusion,Caveolin-1 has a vital role in fluid shear stress-regulated osteoblast proliferation and apoptosis,which may offer a potential therapeutic strategy for osteoporosis.

OBJECTIVE: To review the research progress of Schöttle's method in medial patellofemoral ligament reconstruction (MPFLR), and provide the latest knowledge and suggestions for surgical treatment. METHODS: The studies on Schöttle's method at home and abroad in recent years were extensively collected, then summarized the problems affecting the accuracy of Schöttle's method and the new ideas to improve the accuracy of localization. RESULTS: It's vital to accurately locate the femoral tunnel during MPFLR. Malposition of the femoral tunnel is the main cause of postoperative complications and surgical failure. Schöttle's method is the most well studied and most reproducible method for femoral tunnel localization, which is widely used as the "gold standard". However, there are still problems that affect the accuracy of Schöttle's method, including the impact of the internal/external rotation and varus/valgus of the knee on localization accuracy, unclear requirements for X-ray imaging and anatomical landmark reference line drawing standards, no suitable for patients with anatomical variations, and lack of further research on pediatric patients. In recent years, some new ideas are proposed to improve the Schöttle's method to improve the localization accuracy. CONCLUSION Future research should combine new technologies such as three-dimensional (3D) printing and intraoperative navigation to develop personalized and intelligent Schöttle's method, further improving their localization accuracy.
Humans ; Femur/surgery* ; Plastic Surgery Procedures/methods* ; Patellofemoral Joint/surgery* ; Patellar Ligament/surgery* ; Postoperative Complications ; Knee Joint/surgery* ; Ligaments, Articular/surgery* ; Tomography, X-Ray Computed/methods*

Osteosarcoma （OS） is the most common primary malignant bone tumor originating from mesenchymal stem cells， which features high degree of malignancy， strong invasiveness， easy early metastasis， and high recurrence rate. The clinical manifestations of OS are pain， local mass， limited movement， and pathological fracture. OS mainly occurs in children， adolescents， and the elderly， seriously threatening physical and mental health of patients， as well as their quality of life. The currently available therapies for OS are surgery， chemoradiotherapy， and the combination of the two. Although the therapeutic effect has been improved， tumor recurrence and metastasis and multidrug resistance still occur. Thus， the therapeutic effect is not satisfactory， especially in improving the overall survival rate of patients with metastatic OS. As a result， clinicians and researchers have been making efforts to find an effective therapy. In recent years， the mechanism of curcumin （CUR） against OS has attracted wide attention. CUR， a pigment extracted from the rhizomes or tubers of many plants， such as Curcuma longa， C. rcenyujin， and C. phaeocaulis， has a variety of pharmacological effects. Scholars have found that CUR has the effects of inhibiting proliferation， inducing apoptosis， and reversing multidrug resistance （MDR） of tumor cells， but also it has poor water solubility and low bioavailability， which limit the clinical application. This paper mainly discusses the mechanism of CUR against OS， the existing problems， new treatment methods， and future research directions， which is expected to provide new ideas for scientific researchers and provide a reference for the development and utilization of CUR in the future.

Post-traumatic osteoarthritis (PTOA) refers to the degeneration and destruction of cartilage after trauma to joints and surrounding tissues, along with the damage of subchondral bone, synovium, capsule, muscles and ligaments, finally resulting in osteoarthritis and dysfunction. PTOA of the knee mainly manifests as pain, stiffness and impairment of motion capacity. Management of PTOA includes physical therapy, medication and surgical intervention. Despite the pain was temporarily relieved, the long-term prognosis is still not satisfactory after medication and physical therapy. Surgical intervention is strongly recommended for the moderate and advanced stages of PTOA, which includes arthroscopic debridement, repair of cartilage, osteotomy and arthrodesis. For terminal PTOA, total knee arthroplasty (TKA) is necessary. However, TKA in the treatment of PTOA is challenging, especially for patients with surgical history, poor soft tissue conditions, abnormal alignment, multiple complications, as well as individual variation. Up to now, there is still a lack of standards and consensus for TKA in the treatment of PTOA. Accordingly, the author discusses the issues related to TKA in the treatment of PTOA, aiming to provide a reference for the treatment of PTOA of the knee.

The main function of anterior cruciate ligament (ACL) is to maintain stability of the knee joint and prevent anterior displacement of the tibial plateau. ACL injury accounts for more than 50% of the knee joint injuries. If not timely handled, it will increase the risk of secondary injuries to structures such as the meniscus and cartilage, causing chronic pain and degeneration of the knee joint. Although most ACL injuries can be determined by their direct signs on MRI, the identification of complex situations and partial tears of ACL are still not satisfactory, which subsequently affects treatment strategies. After ACL injury, changes in anatomical relationship of the knee joint can also lead to morphological changes in other structures such as the posterior cruciate ligament (PCL) on MRI, and these indirect signs can assist in the diagnosis of ACL injury. The authors reviewed the application of MRI-related indicators of PCL in diagnosing ACL injury, hoping to provide references and new ideas for clinical decision-making.

Objective To explore the role of miR-199a-3p in osteoblast proliferation induced by fluid shear stress (FSS) and the potential molecular mechanism. Methods Osteoblast MC3T3-E1 was treated with 1. 2 Pa FSS with time gradients of 0, 15, 30, 45, 60, 75 and 90 min, respectively. MC3T3-E1 cells were transfected with miR-199a-3p mimic or miR-199a-3p inhibitor. MC3T3-E1 cells were transfected with miR-199a-3p mimic and itsnegative control and then treated with 1. 2 Pa FSS for 45 min. The pc DNA NC, pc DNA-CABLES -1, si RNA NC and si RNA CABLES-1 were transfected into MC3T3-E1 cells. The pc DNA-CABLES-1 and mir-199a-3p mimic and SI NA-cables-1 and miR-199a-3p inhibitor were co-transfected, respectively. Cell activity was detected by CCK-8 assay. Real-time quantitative PCR (RT-qPCR) was used to detect expression levels of CABLES-1, miR-199a-3p, CDK 6, Cyclin D1 and PCNA. Luciferase reporting assay was used to detect targeting relationship between CABLES-1 and miR-199a-3p. Immunofluorescence was used to detect protein expression of CABLES-1.Western blot was used to detect protein expression of CABLES-1, CDK 6, PCNA and Cyclin D1. Results Mir- 199a-3p in MC3T3-E1 cells was significantly down-regulated by FSS. Over-expressed miR-199a-3p inhibitedosteoblast proliferation, and down-regulated miR-199a-3p expression promoted osteoblast proliferation. miR-199a- 3p could reverse the FSS-induced proliferation in osteoblasts. Dual luciferase assay showed that miR-199a-3p targeted to CABLES-1 and over-expressed miR-199a-3p inhibited expression of CBALES-1 protein. CABLES-1 could promote proliferation of osteoblasts. miR-199a-3p inhibited osteoblast proliferation induced by FSS through CABLES-1. Conclusions FSS-induced osteoblast proliferation can be realized by down-regulated miR-199a-3p expression via targeting CABLES-1. The findings in this study provide new direction for researches on mechanism of FSS-induced osteoblast proliferation, as well as new ideas for future research on clinical application of mechanical loading in the treatment of bone and joint diseases.

Objective:To carry out a scoping review on feeding decision aids in patients with advanced dementia, clarify the characteristics, functions, and application effects of the tools, so as to provide reference for further clinical research.Methods:The research on feeding decision aids for patients with advanced dementia was systematically searched on China National Knowledge Infrastructure (CNKI) , VIP, WanFang Data, and the China Biomedical Literature Library, PubMed, Web of Science, Embase, and Cochrane Library. The search period was from database establishment to August 2022. Two researchers independently selected literature based on inclusion and exclusion criteria, extracted, summarized and analyzed data from the included literature.Results:A total of 8 decision aids were included. The main types included web-based decision aids, paper text decision support manuals, audio manual form decision aids, and a combination of various forms of decision aids. Decision aids provided dementia feeding related information to patients and surrogate decision-makers, analyzed the advantages and disadvantages of different feeding methods, helped clarify their value preferences, and assisted them in making feeding decisions. The evaluation of application effectiveness mainly included outcome indicators such as knowledge, decision conflict, decision regret, decision satisfaction, frequency of doctor-patient communication, and acceptability and effectiveness of decision aids.Conclusions:Decision aids have played a positive role in selecting feeding methods for dementia patients and surrogate decision-makers. Under the background of "Internet + nursing service", we can learn from the experience of foreign research and make full use of artificial intelligence technology to explore scientific and feasible personalized decision aids, so as to provide demand based decision support for patients and their surrogate decision-makers and improve the quality of decisions.

Posterior cruciate ligament (PCL) injury is common in sports medicine. Arthroscopic reconstruction of PCL has become a routine procedure to stabilize the knee joint after PCL injury. The location of tibial tunnel during operation is crucial to a successful surgery. This article reviews the current studies on transtibial PCL reconstruction from the aspects of the anatomy related to the tibial tunnel, the anteromedial and anterolateral tibial tunnels, the maximum angle and optimal angle of tibial tunnel, and the anatomical and non-anatomical tibial tunnels, hoping to provide helpful references for the treatment of PCL injury.