Objective: To analyze the brain imaging features of tree shrews in Alzheimer's disease (AD) model.
Method: Aβ1-40 was injected into the upper cerebral ventricle of the stereotaxic instrument to establish an AD animal model. After visual-spatial behavioral testing confirmed the success of the model, MRI was used for coronal T2-weighted imaging (T2WI) and diffusion tensor imaging (DTI) analysis.
Results: The reference memory errors (3 weeks, 4 weeks) and working memory errors (2 weeks, 3 weeks, 4 weeks) of the model group in the model group were significantly more than those in the control group (P<0.05). The time for the model group to complete the task (2 weeks, 3 weeks) was significantly longer than that of the control group (P<0.05). From 3 weeks, the tree shrews in the model group decreased in unilateral or bilateral hippocampus, and the corresponding lateral or bilateral ventricles increased. At 12 weeks, the width of the bilateral temporal horns of the tree shrews in the model group was significantly larger than that of the control and treatment groups (P<0.01). The diffusion tensor imaging scan showed that the bilateral apparent diffusion coefficient (ACD) of the tree shrew hippocampus in the model group was greater than that in the control group (P<0.01). The corpus callosum fiber bundles in the model group were severely missing.
Conclusion: Injection of Aβ1-40 into the lateral ventricle can cause learning and memory disorders in tree shrews. MRI can show the characteristic changes of AD tree shrew brain. The width of the temporal horn, the ADC value of the hippocampus, and the damage of the corpus callosum fibers have reference value for the diagnosis of dementia.