INS and type 2 diabetes mellitus: Recent data have showed that in obese animals, proinflammatory mediators (namely TNF-α, IL-6, and IL-1β) can damage the pancreatic β cells insulin secretion function in autocrine and paracrine manners, and down-regulate insulin sensitivity in liver and skeletal muscle, jointly inducing the occurrence of IR that is closely related to the development of T2DM (126–128).