血管性痴呆大鼠海马突触结构参数的变化

目的观察血管性痴呆大鼠海马突触结构特点,探讨血管性痴呆学习记忆障碍的神经病理机制. 方法采用永久性结扎双侧颈总动脉的方法建立血管性痴呆动物模型,利用 Morris水迷宫和 Y型电迷宫检验大鼠的学习记忆能力,应用透射电镜和形态计量法分析血管性痴呆大鼠海马 Gray Ⅰ型突触结构参数的变化. 结果血管性痴呆大鼠海马 CA1区 Gray Ι型突触的体积密度、面积密度、比表面、面数密度、突触界面曲率、突触间隙宽度和突触后致密物厚度分别为 0.051± 0.016,(0.298± 0.130) μ m2/m3,(5.884± 1.203) μ m2/m3,(3.285± 1.113)个 /85.05 μ m2,1.048± 0.060,(13.97± 0.386) nm和 (33.33± 0.86) nm],比假手术对照组 分别为 0.088± 0.019,(0.712± 0.815) μ m2/m3,(9.020± 1.915) μ m2/m3,(6.330± 1.258) 个 /85.05 μ m2,1.103± 0.268,(25.40± 0.92) nm和 (47.73± 1.15) nm]减小,血管性痴呆大鼠与假手术对照组突触平均面积分别为 (1.573± 0.343) m2和 (1.202± 0.145) m2. 结论永久性结扎双侧颈总动脉使大鼠海马 CA1区 GrayΙ型突触数量减少和形态结构发生显著变化,导致学习记忆障碍.

Structural changes in the hippocampal synapse of rats with vascular dementia

AIM:To explore the neuropathological mechanism of vascular dementia(VD)-related learning and memory disorder by observing the structural changes of hippocampal synapses in VD rat.METHODS:Rat VD models established by permanent occlusion of the bilateral common carotid artery(POBCCA) underwent Morris water maze and Y maze to assess their learning and memory ability.Structural alternations of Gray typeⅠ synapse of the hippocampus in VD rats were analyzed by transmission electron microscopy and morphological measurement. RESULTS:Structural parameters of Gray typeⅠ synapse in hippocampal CA1 region of VD rats were measured,including the volume density,area density,specific surface area,surface density,synaptic interface curvature,intersynaptic space wideness and postsynaptic density thickness0.051± 0.016,(0.298± 0.130) μ m2/m3,(5.884± 1.203) μ m2/m3,(3.285± 1.113)/85.05 μ m2,1.048± 0.060,(13.97± 0.386) nm and (33.33± 0.86) nm respectively],which were significantly reduced as compared with those in sham operation group0.088± 0.019,(0.712± 0.815) μ m2/m3,(9.020± 1.915) μ m2/m3,(6.330± 1.258)/85.05 μ m2,1.103± 0.268,(25.40± 0.92) nm and (47.73± 1.15) nm, respectively].Synaptic average area in the rats in VD group and sham operation group was (1.573± 0.343) μ m2 and (1.202± 0.145) μ m2 respectively.CONCLUSION:Significantly decreased quantity and structural changes of Gray type Ⅰ synapses occur in the hippocampal CA1 region of VD rats after permanent occlusion of the bilateral common carotid arteries,which may induce learning and memory disturbance.