Trametinib attenuates LPS-induced microglial activation. A. Cultured microglia was treated with 100 ng/ml LPS supplemented or not with 5 or 10 nM trametinib for 6 h. Subsequently, the mRNA expression levels of NOS2, TNF-α, IL-1β, Arg1, VEGF and IL-10 were determined by qPCR, using β-actin as a house-keeping gene. The results were normalized to the control group. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001. B. Cultured microglia were pre-treated with or without 5 or 10 nM trametinib for 2 h and subsequently stimulated with 100 ng/ml LPS for 24 h. Supernatant was collected and the secreting levels of IL-1β, TNF-α, NOS2 and GM-CSF were detected via ELISA. *P<0.05. LPS, lipopolysaccharide; TM, trametinib; Arg1, arginase 1; VEGF, vascular endothelial growth factor.