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Infrasound is the frequency within the range of 0.0001 ~ 20Hz sound waves, which are widely present in the human living environment, penetrating ability, attenuation characteristics. Infrasound on the body's primary mechanism of action is bio-resonance, a large number of studies show that the effects of infrasound on humans and animals can produce a range of biological effects, including central nervous nervous system is sensitive parts of infrasound. Previous studies have found that certain parameters infrasound can cause animal learning and memory function decline may be related to injury of hippocampal neurons, with the extension of time, the intensity increases, the damage gradually increased, but the effect after a certain time, the damage will be reduced , indicating brain tissue infrasound generated adaptability, and infrasound stopping after each damage index with time gradually recovered, indicating different parameters (8Hz/16Hz ,90-130dB) of infrasound certain time caused by the body's damage is reversible, about infrasound brain injury in rat brain tissue self-repair function studies at home and abroad has not been reported. Neural stem cells (neural stem cells, NSCs) refers to the central nervous system with self-renewal capacity and the ability to differentiate to produce the mature brain cells (including neurons, astrocytes and oligodendrocytes) pluripotent cells. Adult mammalian central nervous system, there are two NSCs enclave: the lateral ventricle subventricular zone (Subventricular zone, SVZ) and hippocampal dentate gyrus granule lower (Subgranular zone, SGZ). A variety of brain injury including cerebral ischemia can activate the brain \neurological defects. So we think that infrasound can cause brain damage in neural stem cell proliferation and migration enhance its ability to repair damaged nerves involved, resulting infrasound with time after the animal brain tissue injury decreased. Nestin (Nestin) belong to the first category Ⅵ intermediate filament protein, mammalian nervous system progenitor cells is one of the major cytoskeletal proteins, mainly in the embryonic neural precursor cells and neural stem cells a transient expression. Nestin expression temporal order of terminal differentiation of precursor cells toward the direction of the process to develop into mature cells match; cerebral ischemia, trauma, and physical damage caused by such factors can induce re-expression. Identification of neural stem cells is an important indicator of protein, has been widely used to label neural stem cells. And nestin can be used as the central nervous system injury early, sensitive marker for rapid response may be related to nerve cell repair. Neural cell adhesion molecule (neural cell adhesion molecule, NCAM) is a type of regulating cell-cell, cell-extracellular matrix adhesion between the surface of the membrane glycoproteins, poly sialic acid (polysialic acid, PSA) specificity with NCAM combined, regulating cell-cell interactions. Increase in PSA can reduce the adhesion between cells, to facilitate the growth of nerve and structural remodeling. Experiments confirmed, as well as damage to the nerve growth stage, the brain has a lot of PSA-NCAM expression, suggesting their involvement in the development and nerve repair after injury. And a large number of studies have shown that, PSA-NCAM in NSCs migration plays an important role, directly reflects the migration of NSCs. In this study, the Fourth Military Medical University, Institute of Acoustics, Chinese Academy of Sciences and Aerospace Industry Corporation No. 41 built under the guidance and coordination of the sound source for electric pressure positions the speaker system and infrasound detection systems. Output parameter is 16Hz, 90dB/130dB, rats were exposed to infrasound every position 2h, respectively, the role of 1,7,14,21 d, at different times after the end of infrasound the brain for immunohistochemistry (avidin - biotin - peroxidase complex method, ABC) staining was observed in hippocampus of rats nest of proteins and poly-sialic acid neural cell adhesion molecule expression, and to explore the role of infrasound on rat hippocampal neural stem cell proliferation and migration effects. The results showed that: (1) 168 SD rats were randomly divided into 16Hz, 130dB infrasound group (n = 120), 16Hz, 90dB infrasound group (n = 24) and control group (n = 24). Infrasound rats exposed to 16Hz, 130dB and 90dB of infrasound, 2h / d, respectively, the role of 1,7,14 and 21d. 16Hz, 130dB sound effect in the second group after the end into the end of the day to restore 7d, 14d, 21d and 28d after the group carried out the brain nestin (Nestin) Immunohistochemical staining showed that: ① 130dB group from a role 1d begun rat hippocampus Nestin positive cells began to increase, with the effect increased with increasing frequency, 14d peaked, 21d decreased, but still higher; 90dB rats at each time point Nestin expression weaker than 130dB group. ② After stopping infrasound, 130dB Nestin expression in hippocampal restore 7d peaked and subsequently decreased expression, 28d and reached the lowest values. (2) 96 SD rats were randomly divided into 16Hz, 130dB infrasound and control groups, the infrasound rats exposed to 16Hz, 130dB of infrasound, 2h / d, respectively, and the role of 1,7,14 21d, immunohistochemical staining was observed infrasound and at different time points after exposure today, 7 d and 14 d rat hippocampal PSA-NCAM expression. Study found that: 1 d from infrasound start hippocampal PSA-NCAM staining began to increase, peak continuous role 14d, 21d decreased, but still higher, infrasound stopped functioning after PSA-NCAM expression in the hippocampus gradually decreased, 14d after reached the lowest value, but still higher. These results suggest that, 16Hz, 90dB/130dB infrasound can cause hippocampal Nestin and PSA-NCAM expression is increased, and with the second sound intensity increases, the role of the increase in the number of rat hippocampal expression of Nestin and PSA-NCAM has gradually increased, to 14d peak. Because neural stem cells will migrate to the site of injury to differentiate into new neurons, partial replacement and repair damaged neurons, maintain nerve function, then the damage caused by the proliferation of a large increase in the number of neural stem cells. 14d after Nestin, PSA-NCAM expression began to decrease, probably due to the latter part of infrasound 14d neural stem cells to form new neurons to repair damaged nerves, thus reducing brain injury infrasound levels, resulting in proliferation and migration of nerve also greatly reduce the number of stem cells, which may be caused by experimental animal brain tissue infrasound generated multiple action adaptation of the reasons. After stopping infrasound, over time, gradually reduce the extent of the damage, Nestin and PSA-NCAM expression gradually decreased, neural stem cell proliferation and migration is gradually decreased, indicating their participation in the infrasound brain damage repair mechanisms. This experiment describes infrasound repair mechanisms after injury, better protection for the future subsonic provides a new way of thinking.
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