Study of subependymal ventricular zone and white matter as an endogenous source of cells for white matter repair in neonatal rats with periventricular leukomalacia in vitro

Objective To explore an endogenous self-repair potentiality for injured cerebral white matter from both of subependymal ventricular zone and white matter cell cultures in neonatal rats with oxygen glucose deprivation (OGD) in vitro. Methods The white matter and subependymal ventricular zone tissues from the neonatal rats within 5 days old were separately used to prepare primary glia-derived cell cultures, and these cell cultures were randomly divi-ded into the control group and the OGD group.The double-label fluorescent immunoanalysis was used to observe the proliferation and differentiation of the glia-derived cells came from both of subependymal ventricular zone and white matter activated by OGD.The Hoechst33342/propidium iodide(PI) staining and the flow cytometry technology were used to assess the apoptotic rates of the newborn cells. Results More apoptotic and necrotic cells appeared in the OGD group than those in the control group both in subependymal ventricular zone and white matter cell cultures in the flow cytometry test and Hoechst33342/PI staining at 24 h, 48 h, 72 h, 7 d and 14 d after OGD (all P<0.01). Furthermore, fluorescence microscope showed that the number of the NG2+ progenitor cells, the O4+ oligodendrocyte precursor cells in the OGD group were all significantly more than those in the control group during 72 h after OGD (all P<0.05, 0.01), while the number of the immature and mature oligodendrocytes in the OGD group decreased significantly compared with those in the control group on 7 d and 14 d after OGD (all P<0.05, 0.01). Conclusions OGD may activate 2 endogenous self-repair pathways from subependymal ventricular zone and white matter in vitro.The activated subependymal ventricular zone and white matter-glial progenitor cells appear to proliferate markedly, and differentiate along an oligodendroglial pathway.However, only a few newly generated precursor cells can be differentiated into the immature or mature oligodendrocytes and OGD may induce the newborn cells to appear apoptotic and necrotic. Key words: Periventricular leukomalacia; Oxygen glucose deprivation; Subependymal ventricular zone; White matter; Rat