[Verification of a sporadic Alzheimer disease model in SORL1 gene knockout mice]

Abstract

Objective: To compare the behavioral and pathological features of SORL1 gene knockout mice with those of normal mice and APP/PSE1 mice to verify the feasibility of using SORL1 knockout mice as a model of sporadic Alzheimer disease.

Methods: SORL1 gene of fertilized mouse eggs were edited using Crispr/Case9 technique. SORL1^-/- mice were screened and identified by detecting the DNA sequence, and Western blotting was used to detect the expression of SORL1. SORL1^-/- mice, control mice and APP/PSE1 mice all underwent Morris water maze test to assess their learning and memory abilities with positioning navigation and space exploration experiments. The expression of APP and Aβ in the brain of the mice was detected using immunohistochemistry and Western blotting, respectively.

Results: DNA sequencing showed CAAT deletion in SORL1 gene in two chromosomes of SORL1^-/- mice, and the control mice had intact SORL1 gene without the deletion; Western blotting did not detect the expression of the SORL1 in the brain of SORL1^-/- mice. Morris water maze test showed that in positioning navigation experiment, the average avoidance latency was similar between SORL1^-/- mice and APP/PSE1 mice (P>0.05) but increased significantly in both mice as compared with the control group (P<0.05); similar results were obtained in the space exploration experiment. Immunohistochemistry and Western blotting revealed significantly increased APP and Aβ expression in the brain tissue of both SORL1^-/- mice and APP/PSE1 mice compared with the control mice without significant differences between the two transgenic mice.

Conclusion: SORL1^-/- mice exhibit similar behavioral and pathological changes with APP/PSE1 mice and can be used as a model of sporadic Alzheimer's disease.

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对照小鼠、SORL1^-/-小鼠部分DNA测序图 Partial DNA sequencing result of normal mice and SORL1^-/- mice

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各组小鼠脑组织SORL1蛋白的相对表达量 Western blots (A) and quantitative analysis (B) of SORL1 protein in the brain tissue of different mice. ^*P < 0.05 vs control group; ^▲P < 0.05 vs APP/PSE1 group

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各组小鼠平均穿越平台次数比较 Average number of platform crossing of mice in each group. ^*P < 0.05 vs control group; ^▲P>0.05 vs APP/ PSE1 group

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各组小鼠海马组织APP的表达 Expression of APP in the hippocampus of the mice in each group. a (× 100) and d (× 400) are expression of APP in hippocampus in SORL1^-/- group; b (×100) and e (×400) are expression of APP in hippocampus in control group; c(×100) and f (×400) are expression of APP in hippocampus in APP/PSE1 group

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各组小鼠海马组织Aβ的表达 Expression of Aβ in the hippocampus of the mice in each group. a (×100) and d (×400) are expression of Aβ in hippocampus in SORL1^-/- group; b (×100) and e (×400) are expression of Aβ in hippocampus in control group; c (×100) and f (×400) are expression of Aβ in hippocampus in APP/PSE1 group

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各组小鼠脑组织APP、Aβ蛋白相对表达量 Western blots (A) and quantitative analysis (B) of APP and Aβ protein in the brain tissue of different mice. ^*P < 0.05 vs control group; ^▲P>0.05 vs APP/PSE1 group