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.

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 application effect of target management combined with intelligent display system on apheresis platelet donor recruitment. 【Methods】 Control group: 317 apheresis platelet donors were recruited according to the conventional appointment mode of intelligent display system from October 2020 to March 2021, with a total of 1 073 donations. Experimental group: 404 apheresis platelet donors were recruited using quantitative target management plus the intelligent display system from April 2021 to September 2021, with a total of 1 308 donations. The number of first-time donors, repeated donors, recalled donors after first-time donation, and their corresponding donations, as well as the double-dose collection rate, and the transfer-in/-out of platelet product were analyzed and compared. 【Results】 The number of first-time donors increased from 89 (28.08%) to 179 (44.31%) while repeated donors decreased from 228 (71.92%) to 225 (55.69%), all P<0.05. The number of recalled donors after first-time donation increased from 42 (45.19%) to 82 (47.81%), P>0.05.The cumulative number of first-time and repeated platelet donors increased from 149 (13.89%) to 331 (25.31%), and 924 (86.11%) to 977 (74.69%), respectively(all P<0.05). The recalled donors after first-time donation increased from 60 (40.26%) to 152 (45.92%)(P>0.05). The double-dose collection rate decreased from 24.70% (265/1 073) to 13.46% (176/1 308)(P<0.05). The proportion of transfer-in platelets decreased from 3.64% (48/1 317) to 1.52% (22/1 452), while transfer-out platelet increased from 0.23% (3/1 317) to 2.34% (34/1 452)(all P<0.05). 【Conclusion】 The intelligent display system is conducive to facilitate the development of platelet donor recruitment and ensure the clinical supply of apheresis platelets.

Background and Objectives: The application of adipose derived stem cells (ADSCs) in skin repair has attracted much attention nowadays. Epidermal growth factor (EGF) participates in the progress of skin proliferation, differentiation and so forth. We aimed to explore the role of EGF in the proliferation, invasion, migration and transdifferentiation into epidermal cell phenotypes of ADSCs. Methods: and Results: ADSCs were extracted from adipose tissues from patient. Immunophenotyping was determined by flow cytometry. Overexpressed EGF or siEGF was transfected by lentiviruses. EGF was determined by enzyme linked immunosorbent assay (ELISA) or western blot. ADSCs and HaCaT cells were co-cultured by Transwell chambers. Conditioned medium (CM) was obtained from cultured HaCaT cells and used for the culturing of ADSCs. Cell viability was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Invasion rate was measured by Transwell invasion assay and migration rate by wound healing test. mRNA and protein levels were measured by qPCR and western blot respectively. The extracted cells from adipose tissues were identified as ADSCs by morphology and immunophenotyping. The expression of EGF was up or down regulated constantly in HaCaT cell line after transfection. EGF overexpression upregulated the proliferation, migration and invasion rates of ADSCs, and EGF expression regulated the expression of cytokeratin-19 (CK19) and integrin-β as well. Conclusions EGF could be served as a stimulus to promote the proliferation, migration, and invasion as well as the transdifferentiation into epidermal stem cell immunophenotyping of ADSCs. The results showed that EGF had a promising effect on the repair of skin wound.

Taking the course's characteristics and advantages into account, this study explores the systematic implementation of standardized teaching rounds in the clinical probation sessions of the Dermatology and Venereology course , and evaluates its effect by analyzing the cases of 125 medical students from grade 2015 of Sun Yat-sen University . The results showed that the implementation of standardized teaching rounds has positive effect on the course.

Single arm trial (SAT) was widely used for new drug application (NDA) of novel anti-cancer drugs in recent years. The listing time was greatly shortened by SAT while comparing with randomized controlled trials (RCT). Thus, the companies intended to get NDA through SAT. To encourage innovation and accelerate the developments of anti-cancer agents, we summarize the background and key issues of SAT, discuss the conditions of accepting SAT for NDA, and systematically elaborate the design and principles of SAT in this review.

Single arm trial ( SAT) was widely used for new drug application ( NDA) of novel anti?cancer drugs in recent years. The listing time was greatly shortened by SAT while comparing with randomized controlled trials ( RCT) . Thus, the companies intended to get NDA through SAT. To encourage innovation and accelerate the developments of anti?cancer agents, we summarize the background and key issues of SAT, discuss the conditions of accepting SAT for NDA, and systematically elaborate the design and principles of SAT in this review.

Single arm trial ( SAT) was widely used for new drug application ( NDA) of novel anti?cancer drugs in recent years. The listing time was greatly shortened by SAT while comparing with randomized controlled trials ( RCT) . Thus, the companies intended to get NDA through SAT. To encourage innovation and accelerate the developments of anti?cancer agents, we summarize the background and key issues of SAT, discuss the conditions of accepting SAT for NDA, and systematically elaborate the design and principles of SAT in this review.