Migration And Differentiation Of The Neural Stem Cells Transplanted Into The Rat Hippocampus Damaged By Kainic Acid

BackgroundNeural stem cell is one kind of neural precursor cells that has the features of self-renewal and being induced to differentiate into the three major CNS cell types: neurons, astrocytes and oligodendrocytes.It has been proved that neural stem cells can be found in the majority of fetal cerebra.In the adult mammals, they were found in the subependymal zone of the lateral ventricle and in the dentate gyrus of hippocampus. Depend on the induction of mitogens(bFGF or EGF), neural stem cells can be cultured and expanded in vitro. The neural stem cells transplanted into rat brain can survive, migrate and differentiate into newborn neurons and glials. For the clinical transplanted therapy, people hope to transplant neural stem cells into injured or degenerated brains to rescue the function and even treat some neurodegenerative diseases.We damaged the pyramid cells of CA1 of adult male rat hippocampus by kainic acid, a kind of excitatory amino acid. The neural stem cells derived from the fetal rat hippocampus were then transplanted into the damaged area one week later. We investigated the survival, migration and differentiation of the transplanted cells.Objective1. To study the characteristics of isolation, culturing, proliferation and differentiation of neural stem cells derived from hippocalmpus of embryonic rats.2. To investigate the survival, migration and differentiation of the neural stem cells (NSCs) transplanted into the hippocampus of adult rat damaged by kainic acid.Methods1. Serum-free culture and the techniques of cloning culturing and immunocytochemistry were used to observe the proliferation anddifferention of the neural stem cells derived from hippocalmpus in vitro and to identify differentiated neural cells.2. Loss of hippocampal CA1 pyramid neurons by kainic acid.3. One week later, NSCs labled by Hoechst33342 were transplanted into the damaged hippocampus. The rats were sacrified at 1,2,4 and 8 weeks, and the brains were examined by immunohistochemical analysis.Result1. The neural stem cell isolated from hippocalmpus of embryonic rats had the proliferative ability and alternating generations.Nestin positive cells can be found in the daughter clones.Induced by the 1 % serum, they can attach themselves to wall of culture flask and differentiate into MAP2,GFAP positive cells.2. Kainic acid has distinctive leision to the pyramid neurons of hippocampus CA1.3. Transplanted neural stem cells migrate in the mode of chain in pyramid layer of hippocampus. Most of them express the astrocytic marker of GFAP, others express the neuronal marker of MAP2.Conclusion1. The neural stem cells derived from hippocalmpus of embryonic rats have the ability of proliferation and multipotentiality.2. Kainic acid has some distimctive lesion to the pyramid cell of hippocampus without affecting the input and pass by fibres.3. Transplanted neural stem cells migrate in the mode of chain in pyramid layer of hippocampus.Most of them differentiate into astrocytes, others differentiate into neurons.