Abstract 2523: Isolation And Characterization Of Neural Stem/progenitor Cells From Infarct Area In Neonatal Rat Brains

Abstract

Background and purpose In adult brain, it has been reported newly generated neural stem / progenitor cells survived and differentiated to mature neurons in the severely damaged area after stroke. In neonatal brain, however, it was demonstrated that neurogenesis was stimulated after hypoxia ischemia (HI) and provided neuronal progenitors to the infarct area, but only few new neurons could survive under an unfavorable microenvironment and lack of appropriate trophic support. Recently, neural stem / progenitor cells were isolated from the infarct area in adult mouse brain and elucidated its character as a neural stem / progenitor cell. However, it is still unclear whether the infarct area in neonatal brain has neural stem / progenitor cells as same feature as adult brain. Therefore, the present study was conducted to investigate whether neural stem / progenitor cells could be isolated from infarct area in neonatal rat brain, and to clear its feature. Methods HI brain injury was induced in 7-days-old rat pups by the left common carotid artery occlusion followed by 120 minutes exposure to 8% oxygen. Three days after HI, the brain is removed and sliced at 2 mm thickness, and then six columns are punched out from various infarct areas for cell culture using neurosphere method. The cell clusters are analyzed by immunocytochemistry and mRNA expression for neuron, astrocyte and oligodendrocyte. Also, the cell clusters are investigated the ability of induction for neuron, astrocyte and oligodendrocyte. Results The numbers of neurospere-like cell clusters from infarct areas at 3 days after HI are dramatically increased compared with those from sham control animals. Four and 30 days incubation of the cell clusters provided various types of cells positive for BrdU, Nestin, NG2, β III tubulin, GFAP, O4, Vimentin or Iba1. These cell clusters expressed mRNA such as Nanog, Sox2, Oct3/4 and Rex1 as same as ES cell. Also these cell clusters could be differentiated into neurons, astrocytes or oligodendrocytes, and expressed mRNA such as Nestin, βIIItubulin, GFAP and MBP. Conclusion We have isolated injury-induced neural stem / progenitor cells form ischemic area after neonatal HI. This cell has a potential to use as a source for new neurons driving CNS repair after neonatal HI.