Effect Of NGF On The Proliferation And Differentiation To Astrocyte Of Neural Stem Cells In Wistar Rat Brain With EAE

ObjectiveAcute disseminated encephalomyelitis(ADEM)is a inflammatory demyelinating disease of the central nervous system(CNS).Experimental autoimmune encephalomyelitis(EAE)is T cell mediated demyelinating disease of the central nervous system and serve as a well-established animal model for ADEM.Neural stem cells(NSCs),a type of stem cells,is capable of self-renewal which may be maintained for life-long,proliferation and differentiation like all other stem cells.Accumulating evidence suggests that NSCs is characteristic to differentiate into three main kinds of central nervous system cells:neurons,astrocytes and oligodendrocytes.It has vast clinical application foreground for it's ability of renew and differentiation.Nerve growth factor(NGF),the first target-derived neurotrophic factor to be discovered,is one of the most important biological activity molecules in nervous system.It is necessary for nervous system to maintain the normal growth and function.NGF can promote the transfer and development of embryo neural crest sensory neuron.And participate in the nerve rebirth and the function repairs of the harm,to support the balance between nerve,immunity and the endocrine system.The aim of the present research is to investigate the effects of NGF treatment on the proliferation,differentiation and expression level of NSCs.Methods 1.Choosing the 6～8 weeks Wistar rats were employed.Wistar rats were inoculated intradermal injection with the emulsion homogenate contained spinal cord of guinea pig and complete Freund's adjuvant in feet.2.Immunohistochemical staining was performed to examine the expression of Brdu and BrdU/GFAP in the normal rat brain and the variation law of Brdu and BrdU/GFAP after immuned at different time points including control,7th day after immuned,3th day,7th day,14th day,21st day after onset.3.After the EAE rats were treated with NGF,the proliferative and differentiate effects of nervous stem cells were detected,BrdU and BrdU/GFAP were used to identify proliferative faculty of nervous stem cells and its differentiated potentiality to astrocyte.Results1.The animal got the clinical symptom of EAE at 12th day after immuned;the characteristic light microscopical findings:perivascular inflammatory infiltration,inflammatory cuffs of small blood vessels were evident.2.The Brdu-positive cells were mainly located in subventricular zone of lateral wall and subgranular zone of dentate gyrus in control group.BrdU expressed unequally in different time points,The Brdu-positive cells increased at first,reached a peak at the 3th day after onset,then decreased and back to normal level at the 21st day after onset. Expression of immuno-positive cells of BrdU in treatment group was significantly stronger than EAE group specially at at the 7th day,the 14th day and the 21st day after onset.3.BrdU~+/GFAP~+ expressed unequally in different time points.The BrdU~+/GFAP~+ -positive cells increased at first,reached a peak at the 3th day after onset, then decreased slowly.Expression of immuno-positive cells of BrdU~+/GFAP~+ in treatment group was significantly stronger than EAE group specially at at 7th day,the 14th day and the 21st day after onset,but there were no different at the 7th day after onset and the 14st day after onset.Conclution1.The modeling of EAE is a stable and reliable method.2.Experimental allergic encephalomyelitis can promote the proliferation of NSCs and differentiation to astrocyte.3.Treat with NGF can promote the proliferation of NSCs and differentiation to astrocyte after EAE.