Effect Of Mechanical Vibration On Neuroactive Substances In Fracture Healing Of Ovariectomized Rats After Osteoporosis

Objective : To explore the regulation effect of mechanical vibration intervention on neurological factors in fracture healing of ovariectomized rats.Methods: 1.Osteoporosis: After a week of adaptive feeding,the 45 3-month-old female Wistar rats were Conducted osteoporosis modeling,Intraperitoneal injection of 10% chloral hydrate(0.3ml / 100g)in rats,removal both ovaries of the rats through the back side bilateral incision into the abdominal cavity.2.Fracture modeling: At the fifth month after Rat model of osteoporosis,45 rats were anesthetized with chloral hydrate,cutting off the middle of the femur with a scalpel,and then using Kirschner wire(diameter 1mm)retrograde intramedullary fixation.3.Vibration training intervention: Wistar rats were randomly divided into 15sham-ovarian fracture control groups(Sham),15 ovariectomized fracture model groups(OVX)and 15 ovariectomized fractures(OVX-V).In the OVX-V group,the whole body vibration with a frequency of 35 Hz,a vibration amplitude of 2 mm and an acceleration of 0.5g was performed 5 days after the fracture operation of the rat.Each vibration time was 20 minutes,and the vibration was performed for 5 days per week.The Sham group and the OVX group were placed on a vibratory table for 5 minutes after surgery for 5 minutes without vibration.Real-time-PCR was used to detect the expression of CGRP and SP in fractured end.Western blot was used to detect the expression of sema3 a and FGF23 in the fractured end of rat.Results: 1.Changes in rat fracture site callus structureThe fracture healing rate of the 3 groups sham-operated group(Sham),ovariectomized group(OVX)and ovariectomized vibration group(OVX-V)were compared to each other.X-ray examination showed that the healing rate of the vibration group was better than the control group or the sham group.The healing rate of the Sham group was better compared with the control group.2.The Expression of Neuropeptide CGRP in the Fractures of RatsAfter 2 weeks of fracture in all rats,CGRP in the OVX group was significantly lower than that in the Sham group(P<0.01).Compared with OVX group,CGRP content in bone tissue of OVX-V group was significantly higher(P<0.01),but it was still lower than Sham group.This shows that early intervention in mechanical vibration rehabilitation after osteoporotic fracture can promote the healing of osteoporotic fractures.After 4 and 6 weeks of fracture in all rats,as shown in Table 1 and Figure 5 below,we can easily find that CGRPIV content in bone tissue of OVX-V rats continues to rise and is significantly higher than that of OVX group,and there is a very significant difference.(P<0.01).3.Expression of Neuropeptide SP in Fractures of RatsAfter 2 weeks of fracture in the rat,SP in the OVX group was significantly lower than that in the Sham group(P<0.01).Compared with OVX group,SP content in bone tissue of OVX-V group increased significantly(P<0.01),but was still lower than Sham group.After 4weeks and 6 weeks of fracture in all rats,compared with OVX group,the SP content in bone tissue of OVX-V group continued to increase and was significantly higher than that of OVX group(P<0.01).4.Expression of sema3 a protein at the fracture end of ratAccording to the time trend observation,the sema3 a content in the Sham group showed a gradually increasing trend,while the OVX group and the OVX-V group increased first and then decreased.According to observation at each time period,the expression of sema3 a in bone tissue of OVX rats was significantly lower than that of Sham group after 2 weeks of fracture(P<0.01).The sema3 a content in the OVX-V group was also lower than that in the OVX group(P<0.01).After 4 weeks of fracture in rats,the expression of sema3 a in OVX-V group increased and surpassed that of OVX group(P<0.01).After 6 weeks of fracture in rats,sema3 a in OVX group showed a downward trend,OVX-V group sema3 a.Still higher than OVX but less than Sham.5.Expression of FGF23 protein at the fracture end of ratThe OVX group was significantly higher than the Sham group(P<0.01)in all time periods and showed an upward trend in time.The OVX-V group had significantly lower FGF23 content in the various time periods after the intervention than in the OVX group(P<0.05).<0.01),showing a declining trend over time.This shows that mechanical vibration can reduce the expression of FGF23 in the bone tissue of ovariectomized rats.Conclusion:1.Mechanical vibration can increase the expression of CGRP in the bone tissue,increase the activity of osteoblasts and promote bone formation.2.Mechanical vibration can increase the concentration of neuropeptide SP in the bone tissue,so that the differentiation ability of osteoblasts can enhance the apoptotic capacity,thereby promoting fracture healing.3.Mechanical vibration can upregulate the concentration of sema3 a in bone tissue,so that osteoblast activity enhances the activity of osteoclasts to weaken,so that bone formation is greater than bone resorption and promotes fracture healing.4.Mechanical vibration can reduce the expression of FGF23 in bone tissue,promoteosteoblast differentiation and promote fracture healing.5.Mechanical vibration may promote fracture healing after osteoporosis by regulating neuroendocrine immune network mechanism.