Expression Significance Of Aβ And Tau In Hippocampal CA1Area Of Rats With Vascular Dementia

Objective:①To establish vascular dementia model by ligating the bilateral common carotid arteries in rats.②To observe the behavior and pathological change of brain at different period of cerebral ischemia.③To study the expression of β-amyloid peptide(Aβ)and phosphorylated Tau protein at different period of cerebral ischemia, and explore the relationship between ischemia cerebrovascular disease and VD. To explore the role of Aβ and Tau protein in development of vascular dementia(VD) of rats.Methods:The VD model was established by occlusion of the bilateral common carotid arteries.40SD rats were randomly divided into sham operation group (n=10) and the VD model group (n=30), and the latter group was equally divided into three groups according to the operation time:4,6and8weeks group.The water maze test was performed to examine the ability of learning and memory of the rats.The number of neuron in CA1region of hippocampus in each group was observed with HE stain.Immunohistochemistry staining was used to obverse Tau protein and Aβ in CA1subfield of hippocampus.Results:The ability of learning and memory of VD rats decreased significantly compared to the sham operation rats (P<0.05). The ability of learning and memory in model rats was getting worse with the duration of ischemia, which was the most prominent at the time of four weeks after2VO. The HE stain of operation group showed the pyramidal cells were lost, degenerative and necrotic in quantity, some nuclei were stained deeply and pynotic, and the dendrite of the top was prolonged.In VD group, the expression of Aβ and Tau protein in hippocampal CA1region were the most obvious at4w, and then declined progressively but still above the normal level(P<0.05). Cerebral ischemic injury can lead to brain tissue Aβ protein content and Tau protein hyperphosphorylation, suggesting that cerebral ischemic injury has led to the VD pathological basis.Conclusions:The method of2VO in rats call decrease the ability of learning and memory evidently, which Can be used as a model of vascular dementia. It suggests that the decline of cognition and memory function is related to the increasing of Aβ and Tau protein expression in neuron of hippocampus in VD rats. Aβ and Tau protein may be related to the injury of hippocampus neuronal cells in vascular dementia. It might be one of the reasons causing vascular dementia.