Objective: To investigate the effects of lipoic acid (LA) on the release of TNF-α, IL-1β, IL-6, IL-10 and the expressions of chemokines in astrocytes stimulated with lipopolysaccharide (LPS).
Methods: Astrocytes were separated from the cerebral cortex of newly-born C57BL/6 mice (within 48 h after birth). After identification and purification, the second-generation astrocytes were stimulated with LPS (1 μg/mL), and then treated with LA (100 μg/mL). The production of nitric oxide (NO) was assayed by Griess assay. The levels of TNF-α, IL-1β, IL-6 and IL-10 in supernatants were quantified by ELISA. The expressions of CC chemokine ligand-20 (CCL20), monocyte chemoattractive protein 1 (MCP-1) and macrophage inflammatory protein-1α (MIP-1α) mRNAs were detected using reverse transcription-PCR.
Results: Compared with PBS control, LPS significantly increased the production of TNF-α, IL-1β and IL-6, but decreased the level of IL-10 in cultured astrocytes (P<0.05). LA treatment inhibited LPS-induced NO, TNF-α, IL-1β and IL-6 production, and enhanced IL-10 secretion, and compared with LPS stimulation alone, the differences were statistically significant (P<0.05). In addition, LA treatment also suppressed the expressions of CCL20, MCP-1 and MIP-1α mRNA in astrocytes stimulated with LPS.
Conclusion: LA inhibits neuroinflammatory response in LPS-activated astrocytes. The neuroprotection of LA is partly due to the inhibition of pro-inflammatory cytokines and chemokines derived from astrocytes.