Abstract: Objective To evaluate the effect of permanent hypertension combined with hypoperfusion on the Stroke Prone spontaneously hypertensive rat (SHR/SP) vascular dementia model. Method Male SHR/SP and Wistar rats were randomly divided into SHR/SP sham operation group,SHR/SP model group, Wistar sham operation group and Wistar model group respectively. All rats enrolled in the operation group were undergone a permanent ligation of bilateral carotid artery(2-VO).After the operation, 10 survival rats was available in each group. After 30 days, Morris maze tests were conducted for valuating the learning- memory abilities. Morphological changes of neuron cells and micro-blood vessels was observed. Result In place navigation training, the latency of Wistar sham operation group were less than that of rats in SHR/SP sham operation group, the latency of Wistar model group were less than that of rats in SHR/SP model group, the latency of SHR/SP model group were less than that of rats in Wistar model group (P<0.05). In spatial probe ability test, the trails of rats in SHR/SP and Wistar sham operation groups were concentrated upon platform quadrant, while the those of SHR/SP and Wistar model groups were disorgnized. Neurons loss and micro-blood vessels stenosis of the rats in SHR/SP and Wistar model group groups were severer than that of the rats in SHR/SP and Wistar sham operation groups in the brain region. Conclusion The cognitive function of SHR/SP vascular dementia model was serious than Wistar rat vascular dementia model, both chronic permanent hypoperfusion and hypertension may lead to the loss of neurons and myelin which may result in memory dysfunction. Hypoperfusion is even more harmful than hypertension.

Key words: Dementia, Vascular, SHR/SP, Rats, Morris water maze, Model