| It is said that, in the world wide, the traumatic brain injury has ranked thesecond place in the whole body injury. However, its death rate has reached thefirst place. Most of the traumatic brain injury is caused by the traffic accident,falling down, and body fight. The previous cures to TBI are normallyanti-inflammatory, homeostasis, dehydration, tropic nerve, decompressivecraniectomy, which have little effect. This mainly because the no effectiveresearches like promoting the rebirth of brain cell and the recover of nerves hasbeen made. In addition, the basic reason is that it is of great difficult for therebirth of brain cells. The previous research results show that the neurons are theundifferentiated functioning cells, which have lost the proliferation, making itdifficult to rebirth. The repair of brain tissues and medulla spinalis tissues afterbeing injured mainly depends on the proliferation of neuroglial cells, lacking ofthe rebirth of the corresponding neurons. Therefore this incomplete rebirth hasresulted in the lost of function of nerves, and finally made people into mentallyretarded or being disabled. It is said in one research that the2%(about5.3millions) people in Americans are disabled caused by TBI, making a greatburden for both society and economy. Furthermore, the TBI-based disease is ofsudden attack, quick development and high death rate. Therefore, the diagnoseand cure of TBI is a constantly problem to be solved in need. With the development of iconography and anesthesiology, the cure level of TBI has beenraised greatly. Nevertheless, the high death rate and being disabled rate aftercure of severe brain injury, especially the super severe brain injury is still adifficult problem. It was generally believed that CNS might have experienced aperiod of vulnerability following the injury, during which the neuron could nottolerate a secondary insult. However, amount of experiments shows that there isa window of opportunity to protect the neuron after the TBI, which can decreasethe damage of secondary brain insult. In addition, the brain protection during thebrain protection period would not be stable for many reasons, andelectromagnetic field is served as one of the important factor. With thedevelopment of society and the increasingly use of appliances that emitelectromagnetic radiation, the effects of EMF on humans have already become apublic concern. Preliminary studies have shown that ELFEF could promote thecell proliferation, development and differentiation and it could play theanti-inflammating, easing swelling, alleviating pain, increasing tissueregeneration and decreasing apoptosis roles. Furthermore, EMF can shift thedirection of ion flow and the rheological properties of the blood, as well asexpand blood vessels and accelerate blood flow, thus, they can promote systemiccirculation and improve local microcirculation. Based on the above said biologicaland physical properties of ELFEF, conclusions could be made that the ELFEF couldbe applied to promote the blood circulation, microenvironment, to restrain theneuron apoptosis, and it could make great contribution to the recover of neurontissues following TBI. The following research has been conducted on this basis.Part1The neuroprotective effects of extremely low frequencyelectromagnetic fields on behavior after traumatic brain injuryin ratsObjective: This research aims at the neuroprotective effects of extremely low frequency electromagnetic fields on behavior after traumatic brain injury inrats. Methods: The LFP model has been established. The rats were put in theelectromagnetic field with the15Hz frequency, and were equally divided intofour groups which were subjected to N-EMF, EMF-1G, EMF-3G or EMF-5G,respectively. Afterward, the rats in each group were equally re-divided into7sub-groups, and the rats in each sub-group were exposed to EMF for0.5h,1h,6h,12h,18h,24h or30h, respectively. After the EMF exposure, the animalswere subjected to inject KA to induce apoptosis.24hours after the injection ofKA, the rats were taken into water maze test,beam walking test and open fieldtest to testify the ability of learning and memory. Results: In water maze test,there was no significant difference in the time to find the platform after KAinjection at0.5h post-LFP in within groups. And, the times to find the platformat1h and6h post-LFP were155.45±5.37s and145.36±4.28s, respectively,which were much lower than those at the other time points in the control(non-electromagnetic field) group (P<0.05). In the ELFEF groups, the times tofind the platform at1h,6h and12h post-LFP are likewise much lower thanthose at other time points. With KA injection at1h,6h and12h post-LFP, theplatform finding times were much lower in the ELFEF groups than those in thecontrol group (P<0.05). Among the three ELFEF group, the5G group were ofthe shortest time with no meaning in statistics. The results of beam walking testand open field test were consistent with water maze test. Conclusion: can bedrawn that ELFEF significantly prolongs the window of opportunity for brainprotection to speed up the recover of brain tissues in terms of behavior. Inaddition, the more powerful the strength of electromagnetic field is, the moresignificant the effect is. Part2The neuroprotective effects of extremely low frequencyelectromagnetic fields on morphology after traumatic braininjury in ratsObjective: This research objective at the neuroprotective effects ofextremely low frequency electromagnetic fields on morphology after traumaticbrain injury in rats. Methods: The LFP model has been established. The ratswere put in the electromagnetic field with the15Hz frequency, and were equallydivided into four groups which were subjected to N-EMF, EMF-1G, EMF-3G orEMF-5G, respectively. Afterward, the rats in each group were equally re-dividedinto7sub-groups, and the rats in each sub-group were exposed to EMF for0.5h,1h,6h,12h,18h,24h or30h, respectively. After the EMF exposure, theanimals were subjected to inject KA to induce apoptosis.24hours after theinjection of KA, the rats were deeply anaesthetized and sacrificed. And theimmunohistochemistry, TUNEL, EB extravasation, and Brain water contentwere tested. Results: The EB extravasation results show that in the N-EMFgroup, the EB extravasation levels at1h and6h were dramatically reducedcompared with those at the other time points. In addition, similar effects wereobtained for EB extravasation levels in the ELFEF groups at1h,6h,12h and18h. The three electromagnetic field groups at every point of time weresignificantly lower than the N-EMF correspondingly. Theinmmunohistochemistry, TUNEL, EB extravasation, and brain water contenttests show that in N-EMF group, the results at1h and6h were dramaticallyreduced relative to the other time points. The three electromagnetic field groupsat every point of time were significantly lower than the N-EMF correspondingly.Conclusion: can be drawn that morphologically considered, ELFEFsignificantly strengthen the brain protection after injury in morphological aspect.In addition, the more powerful the strength of electromagnetic field is, the moresignificant the effect is. Part3The neuroprotective effects of extremely low frequencyelectromagnetic fields on molecular biology after traumaticbrain injury in ratsObjective: This research aims at the neuroprotective effects of extremely lowfrequency electromagnetic fields on molecular biology after traumatic brain injuryin rats. Methods: The LFP model has been established. The rats were put in theelectromagnetic field with the15Hz frequency, and are equally divided into fourgroups which were subjected to N-EMF, EMF-1G, EMF-3G or EMF-5G,respectively. Afterward, the rats in each group were equally re-divided into7sub-groups, and the rats in each sub-group were exposed to EMF for0.5h,1h,6h,12h,18h,24h or30h, respectively. After the EMF exposure, the animals weresubjected to inject KA to induce apoptosis.24hours after the injection of KA, therats were deeply anaesthetized and sacrificed.And, the real-time PCR, Western blot,and ELISA tests were introduced respectively to observe the content of HIF-1αandVEGF. Results: In N-EMF group, the HIF-1αand VEGF protein levels at1h and6h were dramatically reduced compared with those at the other time points. The threeelectromagnetic field groups at1h,6h,12h,and18h were significantly lower than it isat other points. However, the results at12h,18h, and24h were of statisticimportance. Conclusion: can be drawn that ELFEF significantly prolongs thewindow of opportunity for brain protection and put it into retardation. In addition,the more powerful the strength of electromagnetic field is, the more significant theeffect is. |
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