| 【Background】Traumatic brain injury is common in clinic and the patients often have sequelaes of aphasia,hemiplegia,personality change and cognitive disorders after TBS. As far as we know, in forensic clinical expertise, the primary methods we use to test the cognitive function are the wechsler adult intelligence scale-revised China (WAIS-RC) and the auditory event-related potentials(AERP) P300. However, we find certain patients can not cooperate with the tester to finish the intelligence scale and the electrophysiology test because of age,education,mental state and other factors in practice, while we can not exclude the disguise of patients. Therefor ,we need to investegate the pathophysiology mechanism of cognitive disorders after traumatic brain injury thoroughly and do more research in the gene level, in order to provide a more reliable and objective testing method and theory evidence for clinical therapy and forensic clinical expertise. Researchs demonstrate that the hippocampus is the important anatomic structure and nerve center of learning as well as the important structure of short-term memory circuit, and it is closely related to the cognitive function. And we can observe the damage of synapse of nerve cell in the hippocampus after traumatic brain injury , such as the change of synapse structure,the alteration of transmission exciation and inhibition and so on. The latest research shows that microRNAs paly an important role in the cell biology process such as the cell differentiation,cell proliferation,cell apotosis,neurogesis,vasculogenesis and so on. Meanwhile , some researches discover the alteration expression of microRNA in hippocampus after traumatic brain injury. However, whether the expression of microRNA regulates the process of cognitive disorders after traumatic brain injury or there is certain correlation between them, nearly no related articles reported.【Objetive】By building up the rat model of traumatic brain injury and detecting the the expression of microRNA in rats'hppocampus, try to investigate the relationship between the microRNA expression profiling in rats'hppocampus and its cognitive disorders after traumatic brain injury.【Method】The rat model of focal brain injury was build up by improved Feeney weight-dropping device, then the auditory event-related potentials(AERP) of control group and injury groups before and after operation was recorded separately in order to reveal the change of rats'cognitive function. The rat of every group was executed and the hppocampus of rat was dissected. After that, the result of histopathological change of rat hippocampus was observed and the expression of microRNA of rat hippocampus was detected by using microarray method.【Results】(1) The histopathological result showed a phenomenon of injury-repair process and neuronophagia in rats'pyramidal cells of hippocampus of the injury group after HE stainning.(2)In injury group, the latency of every compnents of ERP after operation was extened than before operation and the control group, in which the P300 latency was most obvious, while the amplitude had no significant difference. (3) The microarray analysis showed the differential expression microRNAs in rats'hippocampus of injury groups, such as Let -7b,miR-142-3p,miR-22,miR-23a/b,miR-21,miR-132, and so on.【Conclusion】The alteration of rats'P300 after focal brain injury correlate with the up or down regulation of some particular microRNAs in rats'hippocampus, which suggests that the altered expression of microRNA in rats'hippocampus might play an important role in regulating the cognitive disorders after brain injury. |
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