BDH1 and diabetes mellitus: To further determine whether the decrease in fumarate-mediated Bdh1 reduction-induced aggravation of glucotoxicity and lipotoxicity, we established a glucotoxicity and lipotoxicity cell model using Bdh1 siRNA-transfected HK-2 cells in vitro and a streptozotocin (STZ)-induced diabetes mouse model using Bdh1 knockout mice in vivo, and treated them with dimethyl fumarate (DM-Fumarate).