Cell Experimental Study On The Effects Of Sostenuto And Intermittent Low Load Vibration On Fracture Healing

Research background and purpose:With the rapid development of the global economy,the number of patients with high energy injury,such as traffic accident injury and fall injury,has increased year by year.In the above injury,limb injury,especially the incidence of limb fractures is very high,about 5%-10% patients will have delayed union or nonunion of bone fracture,a serious impact on the fracture healing process.Therefore,how to speed up the healing of the fracture,effectively prevent the delayed union or nonunion of fracture has become a hot topic.Nearly ten years of research shows that the low load(frequency 32-37 Hz,acceleration 0.2-0.3g(low-magnitude high-frequency vibration)vibration LMHFV)can promote the growth of bone,osteoporosis,fracture healing.However,most of the literatures reported that the effects of vibration on bone and bone cells are sostenuto vibration loading.However,there are few reports on whether there is any difference between bone and bone cells.Therefore this study by applying a sostenuto low vibration load on cultured MC3T3-E1 cells(sostenuto LMHFV s LMHFV)and intermittent low load vibration(intermittent LMHFV i LMHFV)two low load vibration loading patterns,through the study on the cellular level to explore the intermittent low vibration load on fracture healing will produce different effects and mechanism of action.Research method:Using vibration loading equipment,the MC3T3-E1 cell was applied to the low load mechanical vibration with amplitude 35 Hz and strength of 0.25 g.Divided into blank control group,sostenuto vibration 0.5h group,vibration 15 min intermittent 0.5h,1h,3h,6h and then vibrate 15 min group.The proliferative activity of osteoblasts was detected by MTT at 1,3,5 and 7 days after vibration loading.ALP activity was detected by ALP kit at the end of three days of low load vibration loading.Western-blot and RT-q PCR were used to detect the expression levels of ALP,OCN,COL I,OPG,and RANKL in osteoblasts under low load vibration stimulation.ELISA kit was used to detect the RANKL and M-CSF,two kinds of osteoclast stimulating factor secreted by MC3T3-E1 cell.Experimental results:There was no significant difference between the control group and the control group,no matter which day of the test,the proliferation activity of the continuous and intermittent low load vibration group,and there was no significant difference in the proliferative activity of the sustained low load vibration group and the proliferation activity of the intermittent low load vibration group.The expression of ALP,OCN,COL I and OPG/RANKL ratio of MC3T3-E1 cells in all groups were significantly better than those in control group,and the effect of intermittent 0.5h vibration group was better than that of sostenuto vibration group.Low load vibration inhibited the secretion of RANKL and M-CSF factor in MC3T3-E1 cells,and the secretion of RANKL and M-CSF in the two groups of intermittent 0.5h vibration group and intermittent 1H vibration group was more obvious than that of sostenuto vibration group.Conclusion:Low vibration load(35Hz,0.25g)can promote osteoblast differentiation,and can inhibit the secretion of osteoblast osteoclast stimulating factor,thereby inhibiting osteoclast activity;low load vibration interval of 0.5h to promote the effect of bone cell differentiation is better than sostenuto vibration group;low load vibration had no significant effect on bone formation cell proliferation.