DPP4 and type 2 diabetes mellitus: In order to preliminarily explore whether miR-548ag inhibitor has a role in improving T2DM phenotype, in this study, after intraperitoneal injection of miR-548ag inhibitor adenoviral vector for 6 weeks, glucose tolerance and insulin sensitivity of the db/db mice were significantly improved, and a single tail vein injection of the miR-548ag inhibitor was as effective as 12 gavages of the DPP4 inhibitor, which suggest that miR-548ag inhibitor may become a novel DPP4 inhibitor and a novel therapeutic agent against T2DM.