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 / 中华实用儿科临床杂志

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 divided 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.

Endogenous self-repair in immature white matter induced by ischemia in neonatal rats / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study in vivo the endogenous self-repair mechanism in immature white matter induced by ischemia in neonatal rats with periventricular leukomalacia (PVL).</p><p><b>METHODS</b>Five-day-old neonatal Sprague-Dawley (SD) rats were randomly divided into sham and PVL groups. Rat model of PVL was prepared by ligation of the right common carotid artery following 2 hours of exposure to 8% oxygen. Pathological changes and myelination in the white matter were assessed under light and electron microscopy at 7 and 21 days after PVL. O4-positive OL precursor cells in the white matter were determined with immunofluorescence staining. Activation, proliferation, migration and differentiation of glial progenitor cells in SVZ were observed using immunofluorescent double labeling of either NG2 (marker of progenitor cells) and 5-bromodeoxyuridine (BrdU), or O4 (marker of OL precursor cells) and BrdU.</p><p><b>RESULTS</b>All rats in the PVL group manifested either mild or severe white matter injury under light microscopy, and had higher pathological scores of white matter compared with the sham group at 7 and 21 days after PVL (P<0.05). Electron microscopy showed that the number and thickness of myelin sheath in the PVL group were significantly reduced compared with the sham group (P<0.01). O4-positive OL precursor cells in the white matter observed under fluorescence microscopy were significantly reduced in the PVL group compared with the sham group (P<0.05). BrdU/NG2-positive cells in the SVZ increased significantly in the PVL group 48 hours after PVL and migrated into the periventricular area, reaching a peak on day 7 after PVL. BrdU/O4-positive newborn cells began to appear in the periventricular area 72 hours after PVL, and the number of BrdU/O4-positive cells in the PVL group was statistically more than in the sham group on day 21 after PVL (P<0.05).</p><p><b>CONCLUSIONS</b>Ischemia may induce brain self-repair in neonatal rats, resulting in activation and proliferation of NG2 glial progenitor cells in the SVZ migration and differentiation into OL precursor cells in periventricular white matter.</p>

Effect of single or combined application of UDP-glucose, GDNF and memantine on improvement of white matter injury in neonatal rats assessed with light and electron microscopy pathologically / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To evaluate pathologically the effect of the single or combined application of UDP-glucose, GDNF and memantine on the improvement of white matter injury in neonatal rats with periventricular leukomalacia (PVL) under light and electron microscopy.</p><p><b>METHODS</b>A five-day-old neonatal rat model for PVL was established by ligation of the lateral common carotid artery following 120-minute hypoxia. Rats were randomly divided into six groups (30 rats in each group): sham-operated, PVL, UDP-glucose (UDP-glucose 2000 mg/kg intraperitoneally after PVL), GDNF (GDNF 100 μg/kg intracerebrally after PVL), tmemantine (memantine 20 mg/kg intraperitoneally after PVL), and a combination administration of three drugs (UDP-glucose, GDNF and memantine). The rats were sacrificed 7 or 21 days after PVL for assessment of pathological changes in the white matter under both light and electron microscopy. The number and thickness of the myelin sheath in the white matter were measured under electron microscopy, and both of pathological grading and scoring were undertaken under light microscopy.</p><p><b>RESULTS</b>There was rare and sparse myelinogenesis with a loose arrangement of nerve fibers in the white matter under electron microscopy in the PVL group at 7 and 21 days after PVL. The number and thickness of the myelin sheath in the PVL group were significantly less than in the sham-operated, UDP-glucose, GDNF, memantine and combination administration groups (P<0.01). The results of pathological grading of white matter under light microscopy showed that all rats in the PVL group manifested either mild injury (38%-50%) or severe injury (50%-62%) at 7 and 21 days after PVL. The majority of rats (50%-88%) in the four drug administration groups had normal white matter at 7 and 21 days after PVL. The pathological scores at 7 and 21 days after PVL in the PVL group were the highest, and they were significantly higher than in the other five groups (P<0.05).</p><p><b>CONCLUSIONS</b>The single or combined application of UDP-glucose, GDNF and memantine may significantly improve pathological changes in the white matter of rats with PVL. The favorable effect is inferred to be closely correlated with the improvement of brain microenvironment and the enhancement of nerve regeneration promoted by the three drugs.</p>