FMO5 and endothelial dysfunction: The present study demonstrated that tempol, a radical scavenger improved the reduced FMD (Figure 2), and that the expression of NADPH oxidase subunit p47phox was increased in femoral artery (Figure 3A) as well as apocynin significantly decreased high glucose-induced ROS production in HCAECs (Figure 4H), indicating that the endothelial dysfunction in STZ rats was caused by the increased oxidative stress produced by NADPH oxidase.