Effect of nicorandil on ROS production induced by high-glucose treatment in HCAECs. HCAECs were exposed to high glucose (35.6 mM) for 24 h, and nicorandil (100 µM) for the same period. Representative images show DCF fluorescence in control (A), high-glucose treatment (B) and high-glucose + nicorandil (C). High-glucose treatment increased ROS production, which was prevented by nicorandil (D). *p < 0.05 vs control, #p < 0.05 vs high-glucose (20 cells/dish from 3 dishes). Scale bar = 100 µm.