AD模型小鼠海马和小脑Aβ的沉积与相关miRNAs表达的变化

β-amyloid peptide deposition and expression of related miRNAs in the cerebellum of a mouse model of Alzheimer's disease

目的通过对比观察AD模型小鼠海马与小脑Aβ沉积和相关miRNAs表达的变化,探讨AD模型小鼠小脑是否存在Aβ沉积和相关miRNAs的差异表达。方法选择12月龄大小的APPswe/PS△E9双转基因AD小鼠作为实验组(EG),同月龄的同种系的野生型小鼠C57为对照组(CG),每组各12只。将小鼠脑组织分为左右两部分,右侧脑组织行刚果红染色检测淀粉样物质在海马及小脑的沉积;左侧脑组织分别用于提取海马及小脑的miRNA,应用实时荧光定量PCR方法分别检测两组小鼠海马及小脑组织的miRNA-135a-5p、miRNA-298-5p、miRNA-466b-3p和miR-669f-3p的表达情况。结果刚果红染色:实验组小鼠海马及小脑均可见橘红色的Aβ沉积,对照组小鼠海马及小脑均未见橘红色的Aβ沉积。实时荧光定量PCR:四种miRNAs在实验组海马的表达均低于对照组(P<0.05);miRNA-135a-5p、miRNA-298-5p和miR-669f-3p在实验组小脑的表达低于对照组(P<0.05);miRNA-298-5p和miR-669f-3p在实验组海马的表达低于小脑(P<0.05)。结论 APPswe/PS△E9双转基因AD小鼠小脑中也存在Aβ沉积,其形成可能与miRNA-135a-5p、miRNA-298-5p和miR-669f-3p的表达下调有关。

Objective To investigate the presence of β-amyloid peptide （Aβ） deposition in the cerebellum and the expression of related miRNAs in the cerebellum of a mouse model of Alzheimer disease. Methods Twelve 12-month-old APPswe/PS△E9 double transgenic mice and 12 wild-type C57 mice were sacrificed and the brain tissues were taken for examination. The right hemisphere was stained with Congo red to observe the deposition of amyloid substances, and from the left hemisphere, the hippocampus and the cerebellum were dissected for detecting the expression of miRNA-135a-5p, miRNA-298-5p, miRNA-466b-3p and miR-669f-3p using real-time PCR. Results Congo red staining revealed the presence of Aβdeposition in both the hippocampus and the cerebellum of the transgenic mice but not in the control mice. Real-time PCR showed a significantly lower expression of the 4 miRNAs in the hippocampus in the transgenic mice than in the control mice （P＆lt;0.05）. The expression of miRNA-135a-5p, miRNA-298-5p, and miR-669f-3p in the cerebellum was significantly lower in the transgenic mice than in the control mice （P＆lt;0.05）. The expression of miRNA-298-5p and miR-669f-3p in the hippocampus was significantly lower than that in the cerebellum of the transgenic mice （P＆lt;0.05）. Conclusion Aβdeposition also occurs in the cerebellum of APPswe/PS△E9 double transgenic mice, and its formation might be related to the down-regulation of miRNA-135a-5p, miRNA-298-5p, and miR-669f-3p.