ABSTRACT
Neuroplastin 65 (Np65) is an immunoglobulin superfamily cell adhesion molecule involved in synaptic formation and plasticity. Our recent study showed that Np65-knockout (KO) mice exhibit abnormal cognition and emotional disorders. However, the underlying mechanisms remain unclear. In this study, we found 588 differentially-expressed genes in Np65-KO mice by microarray analysis. RT-PCR analysis also revealed the altered expression of genes associated with development and synaptic structure, such as Cdh1, Htr3a, and Kcnj9. In addition, the expression of Wnt-3, a Wnt protein involved in development, was decreased in Np65-KO mice as evidenced by western blotting. Surprisingly, MRI and DAPI staining showed a significant reduction in the lateral ventricular volume of Np65-KO mice. Together, these findings suggest that ablation of Np65 influences gene expression, which may contribute to abnormal brain development. These results provide clues to the mechanisms underlying the altered brain functions of Np65-deficient mice.
Subject(s)
Animals , Affective Symptoms , Metabolism , Brain , Diagnostic Imaging , Metabolism , Pathology , Cognition Disorders , Metabolism , Gene Expression , Magnetic Resonance Imaging , Membrane Glycoproteins , Genetics , Physiology , Mice, Knockout , Microarray Analysis , Organ Size , Real-Time Polymerase Chain Reaction , Wnt3 Protein , MetabolismABSTRACT
BACKGROUND:Previous studies have demonstrated that cell transplantation has neuroprotective effect on intracerebral hemorrhage,and some researches have indicated that transplantation of bone marrow stromal cells(BMSCs)can promote neural function recovery after cerebral infarction.OBJECTIVE:To explore whether transplantation of BMSCs-modified by gtial cell line-dedved neurotrophic factor gene(GDNF)gene provides a better therapeutic effect than native BMSCs after stroke.METHODS:Totally 36 SD rats were induced intracerabral hemorrhage models by injecting autologous arterial blood,and then divided into 3 groups(n=6).each group was assigned into 2 sub-groups Rabbits in each group were stereotaxically grafted with 20 μL GDNF/BMSCs,BMSCs or saline respectively.The rats were executed at 1 and 2 weeks after operation,and immunohistochemistry was used to observe the expressions of synaptophysin(Syn)and growth associated protein-43(GAP-43)in the margin of the hemorrhagic focus.RESULTS AND CONCLUSlON:Compared with the BMSCs and control groups.both Syn-immunoreactive and GAP-43-immunoreactive products were significantly increased in the GDNF/BMSCs group(P＜0.05).Present results demonstrate that transplantation of GDNF gene-modified BMSCs provides better neuroprotection than native BMSCs delivery for stroke.
ABSTRACT
BACKGROUND: There is few studies addressing the long-playing dynamic observation of cysteinyl aspartate specific protease 3 (Caspase-3) expression following cerebral ischemia/reperfusion.OBJECTIVE: To investigate the effect of transplantation of the neural stem cells (NSCs) modified with gene of glial cell line-derived neurotrophic factor (GDNF) on expression of Caspase-3 in adult Sprague Dawley rats with transient cerebral ischemia.DESING: Randomized controlled animal study.MATERIALS: Sixty Sprague Dawley rats were divided randomly into normal control group (N, n =5), ischemia/reperfusion group (IR, n=5), neural stem cell group (NSCs, n=25) and NSCs modified with gene of GDNF group (GDNF/NSCs, n =25). Several clean neonatal Sprague-Dawley rats were selected to harvest NSCs.METHODS: With the exception of normal control group, models of transient cerebral ischemia were created by modified suture method in other groups. At day 3 following reperfusion, 20 μL NSC suspension containing (4.0-5.0)×10~5 NSCs was infused into rats of the NSC group via right lateral ventricle. An equal volume of GDNF-modified NSC suspension was injected into rats of the GDNF/NSC group. 20 μL saline was infused into the rats of the ischemia/reperfusion group. Animals were anesthetized and sacrificed at week 1 following ischemia/reperfusion in the normal control and ischemia/reperfusion groups. Animals were anesthetized and sacrificed at weeks 1, 2, 3, 5, 7 following ischemia/reperfusion in the NSC and GDNF/NSC groups, 5 rats in each time point.MAIN OUTCOME MEASURES: The strept avidin-biotin immunostaining method was used to observe the distributive characteristics of Caspase-3 in the hippocampus and frontal parietal cortex.RESULTS: Immunohistochemical method (SP) showed that positive capase-3 products expressed in nucleus, cytoplasm and partial neurite. In hippocampus, number of Caspase-3-positive cells was decreased in NSC and GDNF/NSC groups. With the exception of at 1-week reperfusion, number of Caspase-3-positive cells was significantly lessened in the GDNF/NSC group compared with the NSC group at other time points (P < 0.05). In frontoparietal cortex, number of Caspase-3-positive cells was reduced in the NSC and GDNF/NSC groups over time. Except 1 and 2 weeks following ischemia/reperfusion, number of Caspase-3-positive cells was significantly lessened in the GDNF/NSC group compared with the NSC group (P < 0.05).CONCLUSION: Transplanting NSCs modified with gene of GDNF can improve remarkably neural function by deceasing Caspase-3 expression and reducing the nervous cell apoptosis. The transplantation of NSCs modified with gene of GDNF obtained better outcomes compared with NSC transplantation.
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Previous experiments has shown that Ginsenoside Rb1 (GRb1), which is one of the most important active ingredients in ginseng (Panax ginseng C.A. Meyer), reduced infarct and neurologic deficit followed by the transient cerebral ischemia in rats. The mechanism of this neuroprotective function is unclear. In this study, we tested whether the neuroprotective effect of GRb1 is achieved through preventing the neuronal apoptosis and modulating expression of neuronal apoptosis inhibitory protein (NAIP). Focal cerebral ischemia was induced by the middle cerebral artery occlusion (MCAO) in Wistar rats. GRb1 (40 mg/kg, i.p.) was administered immediately after the onset of reperfusion. The rats with neurological deficits were randomly divided into 2 groups: the ischemia and the GRb1 group. Each group was again divided into subgroups according to the various reperfusion time (3 h, 12 h, 1, 2, 3, 5, 10 days, n=4 per time point). Apoptotic cells were analyzed using TUNEL. Immunohistochemical method was used to assess expression of NAIP. This results showed that the number of apoptotic cells elevated at 3 h of reperfusion, and peaked at 24 h, then declined, but the number of apoptotic cells at 10 d after ischemia was significantly more than those of control groups (P＜0.01). Compared with ischemia group, the apoptotic cells decreased at all subgroups of GRb1; however, the significant differences were only found from 12 h to 3 d of reperfusion. In normal and sham groups, NAIP weak immunostaining was diffusely present in the neurons of parenchyma. The number of NAIP-positive cells started to increase in ischemic regions at 3 h after ischemia, peaked at 12 h and declined up to 5 d of reperfusion. At 5 d after ischemia, the number of NAIP-positive cells was less than that of control group (P＜0.05). A few astrocytes strongly expressed NAIP in the ischemic area. In the GRb1 group, the number of NAIP-positive cells from 12 h to 10 d after ischemia was evidently higher than in the ischemia group. Thus, these results suggest that GRb1 has potential ability to prevent apoptosis, the mechanism of which is related to induce expression of NAIP.
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BACKGROUND: In the central nervous system(CNS) of normal adults there are neural stem cells or neural progenitor cells, which are capable of self-renewing and multiple differentiating. In normal physiological conditions, intrinsic neural stem cells are in a resting state. What state will they be in during cerebral ischemia?OBJECTIVE: To observe the distribution, proliferation and differentiation of intrinsic neural stem cells in focal transient ischemia in rats.DESIGN: A randomized controlled exploratory trial based on the rats.SETTING: Neurobiological department, histological and embryological department of a medical college.MATERIALS: The experiment was conducted in the Neurobiological Department of Luzhou Medical College from July 2001 to July 2002. Altogether 41 healthy adult SD rats of either gender, weighting 250 g - 300 g, were selected.INTERVENTIONS: The focal ischemia model was made by blocking middle cerebral artery(MCA) and reperfusing for 0.5 hour, 3 hours, 6 hours, 12 hours, 1 day, 2 days, 3 days, 5 days and 10 days. Sham-operation group was treated by the same method, but the filament was not long enough to block MCA, and normal rats served as control group. The rats were sacrificed at given time points, and their brains were made into cerebral slices. The single-and double-labeled immunohistochemical staining was employed to detect the proliferation, distribution and differentiation of intrinsic neural stem cells.MAIN OUTCOME MEASURES: The distribution, proliferation and differentiation of intrinsic neural stem cells.RESULTS: Immunoreactivity of proliferating cell nuclear antigen(PCNA)was present in most ependymal cells in ventricular zone(VZ), and PCNA-positive cells were sparsely distributed in the parenchyma in normal and sham-operation groups. At 3 hours of reperfusion, PCNA-labeled cells were first detected in rostral subventricular zone. At 12 hours of reperfusion and onward, PCNA-positive cells appeared in some choroid plexus cells in bilateral lateral VZ. At day 3 to day 10 of reperfusion, PCNA-labeled cells significantly increased in infarct boundary in preoptic area, striatum and deep layer of frontoparietal cortex. PCNA-labeled cells were first detected in subgranular zone of dentate gyrus 3 days after reperfusion, and increased with time. A very small number of double-positive cells expressed with PCNA and glial fibrillary acidic protein(GFAP) were first detected in infract boundary in preoptic area on day 3 and onward. No double-PCNA and NF-positive cells were detected within 10 days of reperfusion.CONCLUSION: Focal cerebral ischemia activates intrinsic neural stem cells, which proliferate and differentiate, and migrate toward ischemic striatum and frontoparietal cortex. This may help clarify the mechanism of functional recovery after ischemia.
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Objective To study the transcription level of exogenetic glial cell line-derived neurotrophic factor(GDNF)in rat bone marrow mesenchymal stem cells(BMSCs).Methods The rat BMSCs were isolated and cultured in vitro,and randomly divided into three groups:GDNF-transfected group,blank plasmid-transfected group and non-transfected group.GDNF-transfected group and blank plasmid-transfected group were infected by the recombinant adenovirus of GDNF gene and blank plasmid,respectively.Each of the groups was divided again into 4 subgroups according to the cultured time(3d,6d,9d and 12d)after infection.The transcription level of GDNF gene in BMSCs was tested by quantitative real-time PCR.Results Blank plasmid-transfected group and non-transfected group had no expression of GDNF mRNA,and the relative level of GDNF mRNA transcription was 0.00751?0.00067 in GDNF-transfected group during the following 3~12 days after transfection.Conclusion Gene transfection technoqie mediated by adenoviral vector can transfect GDNF gene into BMSCs with the expression of exogenetic GDNF mRNA.BMSCs transfected with GDNF gene will be used for further research on therapy for the disease of central nervous system.
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The involvement of astrocytes and correlation between neuronal injury and astrocyte response were studied. Blockingmiddle cerebral artery and reperfusing o. 5～48 h, H-E staining, immunoccytochemistry single-and double-labeling, dotble label-ing combined with TUNEL and GFAP immunocytochemistry were used to investigate neuronal injury and astrocyte response.The is chemic area peaked at 24 h of reperfusion. The neurons presented irreversible degeneration at 6 h of reperfusion. At24 h,ischemic area in the preoptic area developed into infarcted area; astrocytes exhibited differential morphological features: reactive,malnourished and degenerative changes. At 48 h of reperfusion, the number of astrocytes began to go up. The astrocytes in is-chemic area didn't proliferate within 48 h. By contrast, a few astrocytes underwent apoptosis. In conclusion, these data indicatethat the reaction of astrocytes is closely connected with the extent of neuronal injuries. The reactive astrocytes imply that astro-cytes positively respond to the neuronal injuries, which might play a role in promoting neuronal survival.
ABSTRACT
Objective To observe the distributive characteristics of glial cell line-derived neurotrophic factor(GDNF)in brain tissue during cerebral ischemia-reperfusion in rats,and its role in ischemic brain damage.Methods The model of focal cerebral ischemia was made by occluding middle cerebral artery(MCA) for 2 h and reperfusion for 0.5～48 h, HE Staining was used to investigate the histological features of ischemic cerebral damage,the immunohistochemical method was used to observe the distributive characteristics of GDNF in brain tissue in rats. Results The focal ischemic areas (including preoptic area, striatum and cortex) presented at 0.5 h of reperfusion and peaked at 24 h. The neurons presented irreversible degeneration at 6 h of reperfusion. At 24 h, the ischemic area in the preoptic area developed into infarct form. At 0.5 h of reperfusion, neurons in ischemic cortex showed GDNF weak positive, neurons in peri-ischemic regions showed GDNF moderate positive. During reperfusion 3～48 h, neurons in ischemic regions showed GDNF negative. Up to 48 h of reperfusion, the active microglias or macroglias in periinfart area strongly expressed GDNF.The number of GDNF positive cells in all groups decreased (P