| BACKGROUD: After cerebral ischemia/reperfusion,the changes of second second messenger systems including Ca2+, c-AMP in neurons activate signal transductions of cells, make CREB phosphorylated and start up gene transcriptions of c-fos,Bcl-2,BDNF,NGF, which take part in neurons regeneration and repair following injury.The activation of astrocytes help ischemic brain repair and prevent from injury.To discuss mechanism of cerebral ischemia/reperfusion and effect of neuroprotective medications, to study the neuroprotection and therapeutic time windows of nimodipine for different degrees focal cerebral ischemia,and to establish experiment base for application of nimodipine clinically, MCAO rats models were made , immunohistochemical expressions of CREB phosphorylation. c-Fos and GFAP were observed between cerebral ischemia-reperfusion rats and medication intervation ones,combining with neurologic deficit score,HE staining for examining morphologic changes after ischemia and brain infarct volumes stereotically measured.The experiments were totally divide into four parts as following:EXPERIMENT 1: AIM To provide reasonable and practicable animalmodels for clinical cerebral ischemia research.METHODS Middle Cerebral Artery Occlusion (MCAO) were carried out on 30 male S-D rats by suture occlusion via intra artery methods.The animals were divided into 5 groups randomly and equally (n=6):group A with 60-min MCAO, group B with 90-min MCAO,group C with 120-min MCAO, group D with 180-min MCAO, group D with sham operation. The neurological outcomes were evaluated at 24 h after the reperfusion.After 72h of reperfusion the brain infarct volumes were measured and HE staining performed respectively on 15 rats. RESULTS HE staining showed penumbra neuron damages aggravated in turns from A to D.Neurological dysfuctions and brain infarct volumes gradually increased from A to D,but there was no significance in brain infarct volume between group B and C. CONCLUSION 90-min-MCAO rats were perfect cerebral ischemia models.EXPERIMENT 2: AIM To investigate c-Fos and GFAP expression following focal cerebral ischemia/reperfusion, To study the suitable neuro-protective time of nimodipine for FCI. METHODS MCAO model was carried out for 90 min by suture occlusion with 60-min BCCAL. 18 male S-D rats were allocated to 6 groups randomly and equally (n=3):control group, ischemia/ reperfusion (I-R) group, preventive group, ischemia treatment group, I-R treatment group and post-reperfusion treatment group.Nimodipine was injected by an intracarotid route. The neurological outcomes and the brain infarct volumes were evaluated respectively at 24h and 72h after the reperfusion. HE staining, c-Fos and GFAP immonohistochemical staining were performed simultaneously. Another 18 same models were equally divided into two groups ,I-R and I-R treatment groups ,each group with 3 subdivions. At 2h (groupAl), 24h (groupA2) and 48h (groupA3) after reperfusion, rats (n=3) were killed and above stainingswere performed. RESULTS HE staining showed penumbra neuron damages alleviated in preventive group,I-R treatment one and post-reperfusion treatment one compared with those in I-R group. Neurological dysfuctions took turns as following after 24 h of reperfusion: ischemia treatment group I-R group> post-reperfusion treatment group > prevention group > I-R treatment group > control group.Infarct volume of each treatment group except that of ischemia treatment one notably decreased (p<0.05) compared with that of I-R group, while increased compared with that of control group. There were significantly differences among those volumes. After therapies, GFAP positive cells in cortex penumbra and CA1 region more reduced than those of I-R group (p<0.05) ,but there were gently reductions of those cells in dentate gyrus. C-Fos expressions of same regions had significant decrease after treatment. Following reperfusion, GFAP clearly expressed at 2h,peaked at 48h and persisted at 72h,while c-Fos reactived strongest at 2h, keep increased till 24h and obviously decreased a...
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