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Objective:To investigate the blocking effect of non-competitive N-methyl-D-aspartic acid(NMDA) receptor antagonist Memantine on glutamate abnormal signal transmission in immature white matter induced by ischemia in vitro and in vivo. Methods:The oligodendrocyte (OL) precursor oxygen glucose deprivation (OGD) cell models of 2-day-old newborn rats were prepared and divided into the normal control group, the OGD group and the Memantine group.The extracellular glutamate level of the OL precursor was measured by high performance liquid chromatography, while the concentration of intracellular calcium and the apoptosis rate of OL precursor were detected by flow cytometry.The animal models of ischemic periventricular leukomalacia (PVL) were established and divided into the sham group, the PVL group and the Memantine group.The pathological evaluation of white matter was performed under light microscope.The positive OL expression rate of myelin basic protein(MBP) was detected by immunohistoche-mistry.The myelination of white matter was evaluated under electron microscope.Results:Compared with the normal control group in vitro, the OGD group had a higher extracellular glutamate level of the OL precursor [(24.60±2.42) μmol/L vs.(9.49±1.08) μmol/L, t=9.28, P<0.01], a higher intracellular calcium concentration [(32.9±6.9)% vs.(6.9±3.5)%, t=4.41, P<0.01], a higher apoptosis rate of the OL precursor [(24.77±2.05)% vs.(6.65±1.39)%, t=15.01, P<0.01]. After treatment with Memantine, the extracellular glutamate level [(14.70±1.70) μmol/L, t=5.68, P<0.01], the intracellular calcium concentration [(23.1±2.0)%, t=6.13, P<0.01], and the apoptosis rate of the OL precursor [(11.80±2.06)%, t=5.18, P<0.01] decreased significantly.Compared with the sham group in vivo, the white matter of the PVL group showed mild or severe pathological changes, and the PVL group had a lower MBP-positive OL expression rate in the white matter [(5.94±1.37)% vs.(15.40±3.22)%, t=4.63, P<0.01]less myelin sheaths (4.00±1.00 vs.14.67±2.70, t=6.11, P<0.01) and thinner myelin sheaths [(33.83±3.21) nm vs.(79.67±6.45) nm , t=10.43, P<0.01]. After the treatment with Memantine, the number of myelin sheaths (10.30±1.50, t=6.01, P<0.01), the thickness of myelin sheaths [(57.21±4.05) nm, t=7.47, P<0.01], and the pathological changes in the white matter of newborn rats ( Z=88.479, P<0.01) all improved markedly, and the MBP positive OL expression rate in the cerebral white matter [(11.02±1.35)%, t=4.40, P<0.05] also increased significantly. Conclusions:Ischemia-induced abnormal signal transmission of glutamate in immature white matter is the important pathway leading to ischemic PVL.Memantine can effectively block the abnormal signal transmission and thus may probably provide a new approach for the effective prevention and treatment of PVL in premature infants.
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Objective To study the protective effect of curcumin on precurosor oligodendrocytes (preOLs) damage induced by hydrogen peroxide (H2O2),and explore its mechanism.Methods (1) In vitro primary culture ofpreOLs was performed; and 0 (normal controls),100,250 and 500 μmol/L H2O2 were added for 30 min; the apoptosis and death of preOLs were observed by Hoechst33342/PI double staining.(2) The preOLs were divided into normal control group,model group,and 5,10 and 20 μmol/L curcumin treatment groups; cells the later three groups were given 5,10 and 20 μmol/L curcumin for one h,and the later four groups were given 100 μmol/L H2O2 for 30 min; MTT assay was,then,employed to detect the cell viability.(3) The preOLs were divided into normal control group,model group,and 10 μmol/L curcumin treatment group; the apoptosis ofpreOLs was detected by Annexin V/FITC flow cytometry; Western blotting was used to detect the protein expressions of B cell lymphoma/leukemia-2 (Bcl2),Bcl-2 associated X protein (Bax) and cleaved caspase-3 and caspase-9; activities of total superoxide dismutase (T-SOD),glutathione peroxidase (GPx) and catalase (CAT) and malondialdehyde (MDA) were detected by spectrophotometry.Results (1) As compared with those in the normal control group,significantly decreased number of normal healthy cells and statistically increased apoptotic and necrotic cells in the 100,250 and 500 μmol/L H2O2 treatment groups were noted (P＜0.05); 100 μmol/L H2O2 treatment group had larger number of apoptotic cells than that of necrotic cells,while 250 and 500 μmol/L H2O2 treatment groups had larger number of necrotic cells than that of apoptotic cells.(2) Cells from 5,10 and 20 μmol/L curcumin treatment groups had significantly higher preOLs viability than those from model group,and 10 and 20 μmol/L curcumin treatment groups had significantly higher preOLs viability than those from 5 μmol/L curcumin treatment group (P＜0.05).(3) As compared with the model group,the 10 μmol/L curcumin treatment group had obviously decreased apoptotic and necrotic cells,increased activities of T-SOD,GPx and CAT,increased GSH level and decreased MDA concentration,up-regulated Bcl-2 expression,and inhibited Bax,caspase-3 and caspase-9 expressions,with significant differences (P＜0.05).Conclusion Curcumin has protective effect on preOLs against oxidative injury through effectively reducing lipid peroxidation,regulating Bcl-2/Bax expression and suppressing caspase-3 and caspase-9 activation.
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Objectives To explore the effect of application of uridine diphosphate-glucose (UDP-glucose) on self-repairment potentiality of immature white matter (WM) in vivo. Methods Five-day-old rats were randomly divided into sham, periventricular leukomalacia (PVL) and UDP-glucose groups. The PVL model was constructed in the PVL and UDP groups, and UDP-glucose (2000mg/kg) was induced by an intraperitoneal injection at once to the rats of UDP group. PVL in-duced proliferation and differentiation of WM-glial progenitor cells invivo were detected by using the three-label lfuorescent immunoanalysis, the apopotosis in WM cell was observed by TUNEL test, and the pathology of WM and myelination were evaluated by light and electron microscopy at day 7 and day 21 after PVL model construction. Results The numbers of new WM-progenitors (NG2+), oligodendrocytes (OLs) progenitor marker (O4+), OL precursors, cyclic nucleotide phosphodiesterase (CNPase+), immature OLs and myelin basic protein (MBP+), and mature OLs in the UDP-glucose group are signiifcantly grea-ter than those in the PVL group at each time interval after induction of PVL (P<0.05). The numbers of the apoptotic cells in UDP-glucose group are less than those in the PVL groups. Under light and electron microscopy, the white matter pathological changes and myelination were found to be better than those in the PVL group (P<0.05). Conclusion The application of UDP-glucose can induce the WM-progenitors to activate, proliferate and differentiate into immature and mature OLs. UDP-glucose can also signiifcantly reduce the apoptotic rate of the WM-new glia cells;improve the white matter pathological changes and the myelin formation.
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BACKGROUND: Periventricular leukomalacia is a major syndrome of premature infant brain injury, which has been not prevented and cured yet. Theoretically, neural stem cells which were transplanted into white matter with an absence of oligodendroglial cells might be an ideal method to cure periventricular leukomalacia. OBJECTIVE: To prepare the multi-lineage potential of neural stem cells for the use of intraventricular transplantation. METHODS: Cerebral cortex was obtained from 12-14-day fetal rats and sectioned into 1.0-mm~3 sections. The single cell suspension was separated and purified. The neurospheres were incubated with DMEM/F12 culture medium containing fetal bovine serum to observe primary and passage culture of neural stem cells. The differentiation of neural stem cells was determined using immunohistochemical method. RESULTS AND CONCLUSION: The viability of cultured neural stem cells was (94.3±2.2)%. The neurosphere was formed at day 3 after primary culture. The proliferation of neurosphere slowed down after 10-passage culture, and some cells became old. All neurospheres were positively Nestin-staining, thus they were considered as neural stem cells. A further incubation of 4-passage neurospheres, immunohistochemical method indicated that the neurosphere was positively GFAP, β-tublin, and O4 staining, respectively. This suggested that cultured neural stem cells are able to self-renew, proliferate, and differentiate into neurons, astrocytes and oligodendroglial cells.
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<p><b>OBJECTIVE</b>To evaluate the neuroprotective effect of memantine, a non-competitive antagonist at the N-methyl-D-aspartate receptor, against hypoxic ischemia (HI) by exploring its regulation on the expression and synthesis of heat shock protein 70 (HSP70) gene in neonatal rat models with cerebral HI.</p><p><b>METHODS</b>Memantine was intraperitoneally injected at a dose of 20 mg/kg in neonatal rat models either before (PRE group) or after (POST group) induction of HI. The expression and synthesis of the HSP70 gene and its corresponding product were determined by rapid competitive PCR and immunohistochemistry, respectively.</p><p><b>RESULTS</b>There was an increase in the expression of HSP70 mRNA two hours after induction of HI, which reached its peak at 48 hours, then decreased gradually. The same expression occurred at relatively low levels in the control group. Also, HSP70 synthesis was detected as early as 2h after HI, reached its peak between 48 and 72 hours, then declined over time. After memantine administration, the expression of the gene and its synthesis of the corresponding product decreased significantly during the time intervals 24 - 72 h for the gene and 48 - 72 h for the product compared to the HI group.</p><p><b>CONCLUSION</b>It was shown that HI is very sensitive to the expression of the HSP70 gene and synthesis of its corresponding product, which could be regulated by memantine. The latter may have the ability to reduce brain damage; thus decreased HSP70 mRNA expression could be a marker for HI. It is suggested that memantine can be a promising agent for neuroprotection against HI, although an overall and objective assessment of memantine is required to see if it can be used on neonates clinically later on.</p>
Subject(s)
Animals , Female , Male , Rats , Gene Expression Regulation , HSP70 Heat-Shock Proteins , Genetics , Hypoxia-Ischemia, Brain , Drug Therapy , Metabolism , Memantine , Pharmacology , Neuroprotective Agents , Pharmacology , Rats, Sprague-DawleyABSTRACT
Objective To investigate the regulatory effects of bombesin on the gastrointestinal morphology and proliferation of mucosa cells in neonatal rabbits. Methods Twenty four neonatal rabbits were divided into big,small dose experimental group and control group. The gastrointestinal morphology in neonatal rabbits was observed by using Video Image Digtal Analysis System and electron microscopy, and the proliferative rate of gastrointestinal epithelium cells was detected by using immunohistochemical assay. Results The villous height of duodenum were (520?76),(513?31),(379?44) ?m in three groups respectively. That in experimental group with big or small dose were significantly higher than that in control group( P
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Objective: To investigate the effects of NO on cholestasis caused by TPN. Methods: 24 newborn rabbits were divided into 3 groups: control group, TPN for 1week group and TPN for 2weeks group. After 7 or 14 days, serum liver function test was determined using automatic biochemical analyzer, NO levels in serum and liver, liver NOS activity and iNOSmRNA expression were determined respectively by the Griess method, spectrophotometric analysis and in situ hybridization. Results: After having received TPN administration for 7 or 14 days, the NO levels of serum and liver, liver NOS activity and iNOSmRNA expression increased significantly than those in control group(P