Study On Correlation Between VEGF And SYP In Hippocampus Following Cerebra Ischemic Reperfusion In Rats

Objective: To observe the expressions of vacular endotheliar growth factor (VEGF) and synaptophysin (SYP) in Hippocampus after rat cerebullar ischemia-and-reperfusion and to investigate vascular neogenesis, synaptic neogenesis, neuronic neogenesis and the correlation among them.Methods: Rat model of cerebullar ischemia-and-reperfusion was made by using bulldog clamp incarcerating common carotid artery.1. Rats were divided into 6 groups at random: immediate execution group, post-ischemia-and-reperfusion 24h group, post-ischemia-and-reperfusion 48h group , post-ischemia-and-reperfusion 3d group, post- ischemia-and-reperfusion 7d group and control group. The expressions of VEGF and SYP were detected in CA1 zone, CA3 zone and DG zone of Hippocampus by immunohistochemical method.2. To observe morphological diversity of neurons in CAl zone, CA3 zone and DG zone of rat Hippocampus and to count the amount of neurons by light microscope.Results:1. The gray scales of the expression of VEGF were increased in immediate execution group, post-ischemia-and-reperfusion 24h group, post-ischemia-and-reperfusion 48h group, post- ischemia-and-reperfusion 3d group, post- ischemia-and-reperfusion 7d group than in control group (P < 0.05). The expression of VEGF reached the peak level in post-ischemia-and-reperfusion 48h group.2. The gray scales of the expression of VEGF were decreased in immediate executiongroup and post-ischemia-and-reperfusion 24h group than control group (P < 0.05). The gray scales of the expression of VEGF were increased in post-ischemia-and-reperfusion 48h group, post- ischemia-and-reperfusion 3d group, post- ischemia-and-reperfusion 7d group The expression of VEGF reached the peak level in post-ischemia-and-reperfusion 48h group. The expression of VEGF tended to decrease in post-ischemia-and-reperfusion 3d group, post- ischemia-and-reperfusion 7d group and had no significant difference with control group (P > 0.05).3. To choose the same sites of the differenet slices in the scope of 50 X 500 (um2) unit area by 100 X 10 light microscope and to count the amount of neurons in DG zone by single blind method: the amount of neurons is higher in various model groups than in control group and reached the peak level in post-ischemia-and-reperfusion 48h group (P < 0.05).4. Neuronic structure changed significantly in the different zones of Hippocampus by light microscope, especially neuronic injury in CA1 zone is most serious.Conclusions:1. The high expressions of VEGF and SYP on earlier period are beneficial to protect the half dark band of ischemia.2. Vascular neogenesis, synaptic neogenesis and neuronic neogenesis is concordant in Hippocampus after cerebullar ischemia.3. There are the different reactions in the various zones of Hippocampus after ischemia. The neuron is most sensitive to ischemia in CA1 zone and the death of the tardive neuron is more extensive. DG zone is the active zone of neuronic neogenesis proliferation.4. The above changes after ischemia have time course, especially the changes is mostobvious on 48 hours.