| Traumatic brain injury, also called brain injury, is damaged brain structure and function by trauma, always develops in traffic accidents, fall, firearm injury accidents and natural disasters, etc. Such high disabling and fatality rate bring huge economic burden and medical care to the society and families. Brain injury is not only a single brain tissue damage, but also includes the primary central nervous system damage, which caused by direct forces. Inflammatory response which afterwards injury and pathological physiology change and bleeding produced secondary damage. Secondary brain injury is the main reason of neurons death and neural dysfunction. It could lead to learning, memory and movement disorders. It is a big problem that treating the brain injury and promoting the recovery of neural function from brain trauma sequela, which has already become a hot research topic. At present, the cerebral edema prevention, intracranial pressure control and mild hypothermia therapy had used in clinical. However, the effect of central nervous system recover is not satisfied. Early intervention of rehabilitation therapy has paid attention by the general medical personnel, and has achieved obvious curative effect. The methods of promoting the neural functional recovery has become a research focus in the rehabilitation medicine, and it also has considerable social significance and the considerable economic value. Physical agent therapy is one of the most important means of rehabilitation therapy. Infrasound is belong to physical agent therapy, and it has barely used at present. Infrasound which exists in environment widely defined as mechanical vibration wave with frequency 0.0001 Hz-20 Hz. Infrasound has low frequency and long wavelength. Therefore, it is not easy to be absorbed by the medium in the process of transmission. Infrasound also has a strong penetrating power, small attenuation and far transmission in the atmosphere. Biological effects of infrasound are relative to intension. Researches have proved that when the sound pressure is more than 90 db, infrasound will damage the organism; when it less than 90 db (which called low sound pressure infrasound), infrasound will protect brain and promot the nerve regeneration. Physiological studies demonstrate that organs have its fixed frequency as 8-12 HZ for head,4-6 HZ for chest,6-9 HZ for abdomen,6 HZ for pelvic cavity and 5 HZ for heart. The fixed frequency is within the range of low sound pressure infrasound. In recent years, some scholars found that the low sound pressure infrasound can produce slight resonance with organisms, which produces the mechanical, thermal, optical, electrical and other physical effect slowly and gently. The low sound pressure infrasound not only doesn’t create damage, but also produce deep massage to biosome. When under the influence of the weaker infrasound, infrasound can strengthen the activation of enzyme which impact body’s antioxidant system, and it can also increase compensatory response. Because of infrasound has low frequency and long wavelengths, the infrasound is not easy to be absorbed and blocked. So it can well spread in the body, through the pathological tissue (cells) easily, reopened the pathological vascular occlusion in organizations, improve the blood circulation of the pathological tissues, provides favorable conditions to promote oxygen, phagocytes, immune globulin and other substances to diseased tissue. Our previous study proved that intervention of low sound pressure infrasound could promote the proliferation and inhibit the apoptosis of BMSCs by unregulated the expression of survivin in 60min. Animal experiments found that low sound pressure infrasound can stimulate the secretion of IGF-1, improve the expression of astrocytes around the ischemic tissue, narrow the infarction area of rat and improve neurologic symptoms significantly. Then we speculate that infrasound could also have therapeutic effect on brain injury. This research choose infrasound intervention for 7 days which had been proved that we can achieve better treatment effect with intervention for 7 days in our previous study. Different length of time ave different results, therefore, this experiment mainly studied the infrasound in 60 min,90 min,120 min intervention time effect on brain trauma.After craniocerebral trauma, brain neuronal markers will be changed, we can evaluate the extent of the repair after craniocerebral trauma by observing the change of these markers. GFAP is the middle of the silk protein and maker of astrocyte, it participate in neurological damage repair and regeneration, and expression in astrocytes richly and specificity. GFAP is the objective marker protein of astrocytes activation, it can maintain the stability of astrocyte morphology, and determines the astrocytes response to nerve injury. Astrocytes can secrete various neurotrophic factors, such as nerve growth factor, brain derived neurotrophic factor, vascular endothelial growth factor, basic fibroblast growth factor and so on, to protect the damaged neurons, improve the synaptic connections, promote restoration of the nerve and nerve function recovery. Astrocytes can also maintain ion balance; adjust the energy metabolism, against oxidative stress. GAP-43 is an axon membrane protein, and a kind of neural specificity protein,GAP-43 play an important role in the nerve fiber growth, development and regeneration, it maintain synapses function and the release of neurotransmitters. GAP-43 has high level expression in neural development and repair, it can adjust axon extension and change the cell morphology, and play an important role for the growth of axons and synaptic building. It is considered to be the inner decision factors of development and regeneration of neuronsObjectiveTo observe mNSS evaluation of rats and explore the effect of infrasound on the expression of glial fibrillary acidic protein (GFAP) and Growth associated protein-43(GAP-43) after traumatic brain injury with the low sound pressure infrasound in Rats. Subsequently, explored the effect of protection and restoration of nerve tissue with the pathological histology observation, demonstrated the treatment mechanism of low sound pressure infrasound after traumatic brain injury in Rats.Methods1. Animals and grouping30 healthy male Sprague-Dawley rats, weight 200-250g, were maintained at a constant humidity and room temperature with free access to food and water.30 SD rats were randomly divided into 5 groups, for the sham group (n=6), model group (n =6),60 minute infrasound group (n=6),90 minute infrasound group (n=6) and 120 minute infrasound group (n=6).2. Animal modelsThe method of Feeney was employed to produce a free-falling model of brain contusion. The anesthetized rats were injected in the stomach using 1% pentobarbital at the proportion of 30 mg/kg, their heads were secured in a prone position and a sagittal scalp incision was made to expose the left parietal bone, and a hole of 1.5 mm was placed by a drill in front of the lambdoid suture and 2.5 mm to the left of the midline, the bone was expanded by a window of 5x5 mm; the impact force of the falling body was 20x30 g/cm that caused brain injury to the left hemisphere. After stopping the bleeding, bone wax was used to seal the bone window and the scalp was sutured. Except for the brain contusion impact, the same steps were repeated in the sham operation group.3. Inclusion and exclusion criteria30 rats which had screened by Zea Longa standard after operated 2-3h had been analyzed in this study. (Zea Longa standard:no nerve damage, can’t stretch the contralateral forelimb, circling towards outboard, tumbling toward opposite-side and lost stepping ability or unconsciousness was defined from 0-4 points. More than 1 point’s means moldings succeed.)4. Processing methodInfrasound groups treated with infrasound for 60 minutes,90 minutes, and 120 minutes separately,7 days in a row. The model groups were treated in the same way without the power, and the sham groups don’t damage the brain and have not infrasound intervention.Curative effect evaluationModified neurological severity scores were scored after 7 days treatment (before death), brain tissue slices were immunohistochemically stained to observe the expression of GFAP and GAP-43 around the brain tissue damage after7days treatment.Statistical methodsUsing SPSS 13.0 version statistical software analyzes. Each set of data as (x± s), using analysis of variance between groups mNSS score and IOD values, using LSD method between two groups compare,with P< 0.05 as statistically inspection standard.ResultsThe mNSS score are different between the infrasound groups and the model group (P<0.05); There are no difference among the infrasound groups (P>0.05). Immunohistochemical results:① the integral optical density (IOD) of GFAP was significantly different among the five groups (P<0.05); There was significantly different between the infrasound groups and the model group (P<0.05); There was no significant difference within the infrasound groups (P>0.05). ② the integral optical density (IOD) of GAP-43 was significantly different among the five groups (P<0.05); There was significantly different between the infrasound groups and the model group (P<0.05); There was no significant difference within the infrasound groups (P>0.05)Conclusion1, Infrasound treatment can reduce the mNSS assessed total score significantly, and promote the recovery of neurological function.2, The expression of GFAP was over-expressed in infrasound groups3,The expression of GAP43 was over-expressed in infrasound groups4, There was no significant difference within the infrasound groups of the expression of GFAP and GAP-43, we speculate that: ①the rats can produce adaptation phenomenon with low sound pressure level of infrasound more than 60 min every day.5, Low sound pressure level of infrasound has neuroprotective effects on cerebral ischemia and reperfusion in rats. |
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