A Preliminary Study On The Effects Of Brain-Derived Mitochondria On The Function Of Neurons And Vascular Endothelial Cells After Traumatic Brain Injury

Objective: along with the development of large transportation tools,the incidence of Traumatic brain injury(TBI)is increasing year by year,which has a serious impact on people’s work and life,and the social impact is huge.To accelerate and deepen the degree of recovery after traumatic brain injury is the direction of clinical work of neurosurgery.Therefore,the mechanism of repairing the vascular nerve after brain injury has been a serious problem in the study of brain injury.Recently,researchers have found that neurons can release and transfer damaged mitochondria to the surrounding astrocytes,which are further processed.It is also suggested that astrocytes can release vesicles containing functional mitochondria into damaged neurons and promote repair of neurons.As the researchers described above,the study does not confirm whether mitochondria themselves at work,so we design this topic to study purified mitochondria which can be absorb using again by cells,so as to improve the function of receptor cells,and thus we speculated that the exchange ability of mitocho ndrial may represent a variety of central nervous system cells of the energy transfer between a potential model.In turn,it provides a new idea for the repair of nerve vessels after traumatic brain injury.Methods:(1)we adopted the international and stable glioblastoma cell line(C6)to obtain the vesicles containing mitochondria,and to determine its size function and quantity by flow cytometry.(2)using mouse isolated brain tissue to extract ultra-pure mitochondria,the mitochondrial morphological characteristics and surface specific protein molecules were detected by scanning electron microscopy and flow cytometry.The function and activity of purified mitochondria were determined by O2 K and mitochondrial membrane potential detector.(3)the low-oxygen hypoglycemic injury model of neurons and endothelial cells was established by using low-oxygen culture box,and compared the activity of the two cells before and after the mitochondrial intervention,and the oxygen consumption ability and other related indicators.(4)using the cerebral cortex in jury instrument(CCI)to prepare the model of craniocerebral trauma mice,and purified mitochondria through the tail vein of the mouse,and then the leakage of Evans blue of the blood-brain barrier was detected.Immunofluorescence and western blot were used to detect the changes of closely related proteins in the endothelial cells of the wound lesions in brain trauma mice.The Long-Term Depression(LTD)of CCI mice was enhanced,and the cognitive function of mice after traumatic brain injury was improved.Results: with the method of in vitro cultured cells to obtain purified mitochondrial scheme,due to the low yield,mass culture cell experiment too trival,we adopt mitochondria in vitro isolation and purification of brain tissue.And the successful application of percoll density gradient centrifugation method to obtain ultra-pure mitochondria successfully measured mitochondrial size and concentration.The mitochondria were isolated by transmission electron microscopy and western blot.Using fluorescent dye metotraker to mark the mitochondria,it proved that neurons and endothelial cells could eat free mitochondria.In vitro experiments have established that fresh purification mitochondria increased neuronal activity and the mitochondria can promote both high expression of synapto physinⅠ,GAP and increase endothelial cells ZO-1,OCLN expression increased.The experimental results showed that the fresh purified mitochondria could reduce the permeability of blood brain barrier after CCI.Western blot technology confirmed that the expression of zo-1and OCLN expression increased.In vivo experiments show that fresh purified mitochondria can reduce the blue permeability of the blood-brain barrier after traumatic brainl injury.Animal experiments further confirmed that the improvement rate of exogenous brain-derived active mitochondria after CCI significantly increased cognitive function.Conclusion: the mechanism of energy transfer can be achieved by transferring mitochondria between the inner cells of the central nervous system.We adopt fresh purification mitochondria can improve neurons after TBI and endothelial cell energy metabolism,improve the synaptic plasticity of neurons,improve the cognitive function of mice after traumatic brain injury.Because the mitochondria are relatively easy to obtain and safe,it is believed that further basic and clinical research can open a new door to the rehabilitation of brain trauma.