Research On Electrical Conduction Pathway Of Locally Transplanted Neural Stem Cells For Brain Damage Repair

Background:Traumatic Brain Injury(TBI)refers to a disease caused by external mechanical forces directly or indirectly acting on the head resulting in the defect of brain tissue and neural functional disorder,which has a high disability rate and mortality all over the world.It brings a huge burden to families and social economy.Due to the complexity and fragility of brain tissue structure,TBI often causes irreversible damage.Furthermore,the Central Nervous System(CNS)lacks the ability to repair itself completely.Despite the continuous development of medical emergency,intensive care,medical imaging and rehabilitation medicine,there is not an exact clinical treatment strategy to completely reverse the pathological damage of TBI or improve the neurological dysfunction caused by TBI,seriously affecting the quality of life of patients in the future.Neural Stem Cells(NSCs)are a type of cell population with self-renewal,highly proliferative and multi-directional differentiation potentials,as well as the ability of neural repair,immune regulation and nourishing nerves,which provide a new idea for the treatment of neurological diseases such as traumatic brain injury.A sufficient number of exogenous neural stem cells transplanted into the brain can secrete exogenous neurotrophic factors,improving the microenvironment surrounding the injury and providing nutritional support for neural tissues,and also be integrated into the central nervous system and participate in the reconstruction of neural tissue structures.It has been proven to effectively make up for the loss of neural stem cells and has broad application prospects.Although many experiments have shown that neural stem cells transplanted into rat brain could survive and differentiate into neurons,and accelerate the improvement of neurological dysfunction through the pathological observation and motor function measure.However,the relationship between the recovery of neural function and the neural network repaired and rebuilt after transplanting exogenous neural stem cells needs to be further explored by neuroelectrophysiological techniques.Objective:In this study,we locally transplanted neural stem cells isolated,cultured and identified in vitro into the injury cavity of TBI rats.Using motor behavior score to evaluate the repair of neurological dysfunction in TBI rats,and detecting the Somatosensory evoked potential(SEP)and motor evoked potential(MEP)to explore the integrity and rehabilitation of function of electrical conduction pathway after locally transplanting neural stem cells for brain damage repair.Methods:Taking 1 to 3 days’ newborn SD mice,mechanically extracting NSCs from the cerebral cortex tissues.After 3 weeks of screening culture,the suspended cells were identified by immunofluorescence staining.The improved Feeney’s method of free-fall impact was applied to build a controlled rat cortical impact model.One week later,NSCs were transplanted into the brain of TBI rats.The modified Neurological Severity Scores(mNSS),Limb use asymmetry test,SEP and MEP were performed at the time of before and 6d after TBI,and 7d,14d,21d post transplantation.Results:1.A large number of cells isolated from the cerebral cortex of newborn rats could be continuously cultured and be aggregated to form stable suspended neurospheres,whose positive rate of Nestin/DAPI immunofluorescence staining was over 90%.2.There was significant difference in mNSS between transplanting group and transplanting control group at 14d,21d post transplantation(P<0.05).There was significant difference in Limb use asymmetry test between transplanting group and transplanting control group at 21d post transplantation(P<0.05).There was significant difference in latency of SEP and MEP between transplanting group and transplanting control group at 14d,21d post transplantation(P<0.05).Conclusion:1.The cerebral cortex of newborn SD rats was rich in neural stem cells.NSCs isolated and cultured in vitro own the ability of continuously proliferation and self-renewal.They could converge to form stable suspended neurospheres and still have good biological characteristics of neural stem cells after subculture.2.According to the assessment of mNSS and Limb use asymmetry test,the neurological dysfunction of TBI rats was improved within 3 weeks after the transplantation of the mixture of NSCs and hydrogel,but the long-term efficacy and the specific treatment mechanism remained to be further studied.3.According to the detection of SEP and MEP,the latency was shorter in the transplanting group compared with that in transplanting control group and simple injury group,suggesting that the transplantation of exogenous NSCs can promote the rehabilitation of electrical conduction pathway after TBI.