High glucose stimulates TNFα and MCP-1 expression in rat microglia via ROS and NF-κB pathways

Aim: To investigate whether high glucose stimulates the expression of inflammatory cytokines and the possible mechanisms involved. Methods: ELISA and real-time PCR were used to determine the expression of the inflammatory factors, and a chemiluminescence assay was used to measure the production of reactive oxygen species (ROS). Results: Compared to low glucose (10 mmol/L), treatment with high glucose (35 mmol/L) increased the secretion of tumor necrosis factor (TNF)alpha and monocyte chemotactic protein-1 (MCP-1), but not interleukin (IL)-1 beta and IL-6, in a time-dependent manner in primary cultured rat microglia. The mRNA expression of TNF alpha and MCP-1 also increased in response to high glucose. This upregulation was specific to high glucose because it was not observed in the osmotic control. High-glucose treatment stimulated the formation of ROS. Furthermore, treatment with the ROS scavenger NAC significantly reduced the high glucose-induced TNF alpha and MCP-1 secretion. In addition, the nuclear factor kappa B (NF-kappa B) inhibitors MG132 and PDTC completely blocked the high glucose-induced TNF alpha and MCP-1 secretion. Conclusion: We found that high glucose induces TNFa and MCP-1 secretion as well as mRNA expression in rat microglia in vitro, and this effect is mediated by the ROS and NF-kappa B pathways.