Neuroprotective effects of Lycium barbarum polysaccharides in lipopolysaccharide-induced BV2 microglial cells

Polysaccharides extracted from Lycium barbarum (LBPs) possess a wide variety of biological activities. However, their neuroprotective effects have not yet been fully elucidated. The aim of the present study was to investigate the inhibitory effects of LBPs on the production of lipopolysaccharide (LPS)-induced proinflammatory mediators in BV2 microglia. BV2 mouse microglial cells were cultured and an MTT assay was performed to determine whether LBPs had an effect on the apoptosis of LPS-stimulated BV2 cells. Our data showed that LPS induced the activation of nuclear factor-kappa B (NF-kappa B) and its upstream protein caspase 3, upregulated the expression of an additional apoptosis-inducing factor, heat shock protein 60 (HSP60), in BV2 microglial cells and increased the release of TNF-alpha and HSP60 in the culture media. Following treatment with LBPs, the activated NF-kappa B and caspase 3 were significantly suppressed. Furthermore, the enhanced expression of HSP60 was reduced and the LPS-induced release of TNF-alpha and HSP60 were inhibited. These results suggest that LBPs may have therapeutic potential for the treatment of neurodegenerative diseases that are accompanied by microglial activation.