Figure 4.

Linagliptin reduces Aβ‐induced intracellular ROS accumulation and improves mitochondria dysfunction. (A) Effects of linagliptin (50 μM) in reducing 2.5 μM of Aβ‐induced intracellular ROS accumulation determined by dichlorofluorescin diacetate (DCFH‐DA) staining under microscope. (B) Effects of linagliptin (50 μM), Aβ (2.5 μM), and LY294002 (20 μM) on Thr¹⁷² phosphorylation of AMPK, and the protein levels of AMPK, Sirt1 and SOD1 by immunoblotting. (C) JC‐1 immunofluorescent staining. Green fluorescence represents Aβ‐induced mitochondrial dysfunction by dissipation of mitochondrial membrane potential. Red fluorescence indicates that co‐treatment with linagliptin (50 μM) preserved an intact mitochondrial membrane potential compared with the group treated with Aβ (2.5 μM) alone. LY294002 (20 μM), a specific inhibitor of PI3‐kinase. Scale bar represents 20 μm.