β淀粉样蛋白和Tau蛋白在血管性痴呆发病机制中的作用

EFFECT OF β-AMYLOID PROTEIN AND TAU PROTEIN ON THE MECHANISM OF VASCULAR DEMENTIA

目的:观察β淀粉样蛋白和Tau蛋白在血管性痴呆(VD)大鼠发生、发展中的作用。方法:采用永久性结扎双侧颈总动脉方法建立VD模型。40只SD大鼠随机分为假手术组(10只)、模型组(30只)。模型组按手术时间又分为4,6,8周组,每组n=10只。应用Morris水迷宫检测大鼠的学习、记忆能力;免疫组化染色方法检测大鼠海马CA1区β淀粉样蛋白和Tau蛋白的表达;用HE染色观察各组大鼠海马CA1区神经元数目的变化。结果:与假手术组比较,模型组大鼠术后4,6,8周学习记忆能力明显下降(P<0.05)。海马CA1区细胞排列疏松,数目减少,细胞形态异常。模型组大鼠海马CA1区β淀粉样蛋白和Tau蛋白的表达于缺血4周时表达最明显,6周和8周表达缓慢下降,但与假手术组比较仍处于较高水平(P<0.05)。结论:VD大鼠认知功能、记忆功能减退与Aβ和Tau蛋白表达增加有关,并可能参与缺血后海马神经元的损害,是构成VD的机制之一。

Objective：To investigate the effect of β-amyloid protein and Tau protein in the development of vascular dementia（VD） of rats.Methods：The VD model was established by occlusion of the bilateral common carotid arteries.Fourty SD rats were randomly divided into sham operation（n=10） and VD model groups（n=30）,and the latter group was equally divided into three subgroups according to the operation time：subgroup 4-,6-,and 8-week.The water maze test was performed to examine the ability of learning and memory of the rats.The number of neuron in CA1 region of hippocampus in each group was observed with HE stain.Immunohistochemistry staining was used to obverse the expression of Tau protein and β-amyloid protein in CA1 subfield of hippocampus.Results：The ability of learning and memory of VD rats decreased as compared to the sham operation rats（P0.05）.HE stain of operation group showed that 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 β-amyloid protein and Tau protein in hippocampal CA1 region was the most obvious at 4-week,and then declined progressively but was still higher than the normal level（P0.05）.Conclusion：It suggests that the decline of cognition and memory function is related to the increasing of β-amyloid protein and Tau protein expression in neuron of hippocampus in VD rats.Tau protein and β-amyloid protein may be related to the injury of hippocampus neuronal cells in vascular dementia.It might be one of the reasons causing vascular dementia.