ATF6 and diabetes mellitus: Biochemical markers (MDA, GSH, SOD), histopathology, and expression of ER stress and apoptotic proteins (ATF6, IRE1, Caspase-3, BCL-2, CREB, TNF-α, and IL-1β) were evaluated.<h4>Results</h4>The DM group exhibited significant increases in MDA, TNF-α, IL-1β, ATF6, and Caspase-3 with reduced GSH, SOD, and BCL-2, indicating oxidative stress, inflammation, apoptosis, and ER stress.