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

Area of Science:

• Neuroscience
• Immunology
• Endocrinology

Background:

• Hyperglycemia is a hallmark of diabetes and is associated with chronic inflammation.
• Microglia, the resident immune cells of the brain, play a critical role in neuroinflammation.
• The precise mechanisms by which high glucose induces microglial activation remain incompletely understood.

Purpose of the Study:

• To investigate the effect of high glucose on the expression of inflammatory cytokines in primary rat microglia.
• To elucidate the underlying molecular mechanisms, including the roles of reactive oxygen species (ROS) and nuclear factor kappa B (NF-κB) signaling.

Main Methods:

• Primary rat microglia were cultured and treated with varying glucose concentrations.
• Enzyme-linked immunosorbent assay (ELISA) and real-time PCR were used to quantify cytokine expression (TNFα, MCP-1, IL-1β, IL-6).
• Chemiluminescence assays measured reactive oxygen species (ROS) production.
• Specific inhibitors and scavengers (NAC, MG132, PDTC) were used to investigate signaling pathways.

Main Results:

• High glucose (35 mmol/L) significantly increased the secretion and mRNA expression of TNFα and MCP-1 in a time-dependent manner.
• Interleukin-1β and IL-6 expression were not significantly affected by high glucose.
• High glucose stimulated ROS production, which was attenuated by the ROS scavenger N-acetylcysteine (NAC).
• Inhibition of NF-κB signaling completely blocked high glucose-induced TNFα and MCP-1 secretion.

Conclusions:

• High glucose induces the secretion and mRNA expression of TNFα and MCP-1 in rat microglia.
• This pro-inflammatory effect is mediated by ROS generation and activation of the NF-κB pathway.
• Findings highlight potential therapeutic targets for managing high glucose-induced neuroinflammation.