Activation of α7 nAChR promotes the expression of SYN in Aβ oligomer-treated neurons. (A) Hippocampus cells isolated from WT mice (control), (B) control treated with PNU (PNU), (C) control treated with Aβ (Aβ) and (D) control treated with PNU and Aβ (PNU+Aβ). (E) The IOD of SYN in the hippocampus neurons. (F) The IOD of Aβ in the hippocampus neurons. SYN, Aβ oligomers and the nuclei were labeled green, red and blue, respectively. Magnification, x200. Compared with the (A) control group, the expression level of SYN (green) was significantly decreased in the (C) Aβ oligomer group, (D) and this decreasing was partially reversed by PNU treatment. Data are presented as the mean ± standard deviation. *P<0.05, **P<0.01 vs. control group; #P<0.05, ##P<0.01 vs. Aβ group.