| Research background and purpose:Bone plays a supporting role in the human body.With the improvement of people’s living standard and the development of medical level,the life span of the patients is generally prolonged.The number of patients with osteoporosis and various causes of fracture is increasing year by year.The delayed union of fracture and the nonunion of fracture are an important issue for doctors in Department of orthopedics.Studies have shown that the probability of osteoporotic fracture in old fracture is 69.4%.Most of the clinical treatment of osteoporosis and fracture is the use of drugs and surgical treatment,although it has a certain effect,but it also brings a lot of side effects.In recent years,research has found that appropriate stress stimulation can promote bone formation,but different stress intensity and frequency affect the effect of bone formation.In recent years,experimental research has proved that continuous and intermittent low load mechanical vibration(frequency 32-37 Hz,acceleration 0.2-0.3g)can promote bone growth,promote fracture healing,and combat osteoporosis.Our research group has been studied for years in the low load mechanical vibration promotes the growth of bone,osteoporosis,this subject is mainly in the intermittent low load mechanical vibration loading conditions,the specific Wnt/-catenin signaling pathway,beta blocker Dkk1,cell skeleton and other aspects of the intermittent low load vibration to promote bone mechanism on MC3T3-E1 cells.It provides a new treatment idea and theoretical support for the treatment of osteoporosis and the promotion of fracture healing in the future clinical work.Experimental methods:1.The regulation of Wnt/ beta-catenin signaling pathway and Runx2 factor in MC3T3-E1 cells by continuous and intermittent low load mechanical vibrationMethods: basic control group(Control): blank control group,loading vibration daily.Daily vibration 30min(SV0.5h): the daily implementation of the continuous 30 min vibration loading.Daily vibration 15 min * 230 min interval(IV0.5h): two times the daily implementation of 15 min vibration loading during intermittent 30 min.RT-q PCR and Western blot were used to detect the expression of beta-catenin m RNA,Runx2 m RNA,and beta-catenin protein in cells.2.The regulation of Wnt/ beta-catenin pathway on MC3T3-E1 osteogenesis effect under continuous and intermittent low load mechanical vibrationMethods: the experiment was divided into four groups,control group(Control),two times the daily implementation of 15 min during intermittent vibration loading,group 30min(IV0.5h)+DKK1(0.2mg/m L)group,DKK1(0.2mg/m L)treatment group,daily two times each 15 min during intermittent vibration loading,30 min group(IV0.5h group).About when cell wall growth to 70%,a blocker group and antagonist DKK1(0.2mg/m L),without blocking agent group with the same dose of PBS was placed in the incubator for 48 hours,then load vibration group began applying intermittent low load mechanical vibration,vibration loading is not the same regardless of group environment but not applying the intermittent low load mechanical vibration.Conclusion:1.Both continuous and intermittent low load mechanical vibration can promote the osteogenic effect of the cells,and the mechanical vibration of intermittent low load is more effective.2,during the intermittent low load mechanical vibration,the expression of beta-catenin protein,Runx2 gene and protein increased,indicating that intermittent low load mechanical vibration can promote osteogenic effect of MC3T3E1 cells and activate Wnt/ beta-catenin signaling pathway.3,both continuous and intermittent low load mechanical vibration loading or not,a specific inhibitor of Dkk1,Wnt/ beta-catenin signaling pathway activity was inhibited,the expression of Runx2 gene and protein level decreased,proved that the intermittent low load mechanical vibration of the up regulation of Runx2 gene to promote osteogenic effect of Wnt/ beta-catenin signaling pathway is involved in the role. |
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