Mechanism of Lycium barbarum polysaccharides on primary cultured rat hippocampal neurons

Lycium barbarum polysaccharides (LBP) have been reported to have a wide range of beneficial effects including neuroprotection, anti-aging and anticancer. However, the anti-inflammation mechanism of LBP on primary cultured rat hippocampal neurons injured by oxygen-glucose deprivation/reperfusion (OGD/RP) is incompletely understood. We investigate the neuroprotective effects of LBP on neonatal rat primary cultured hippocampal neurons injured by OGD/RP with different approaches: MTT assay was used to detect cell viability, lactate dehydrogenase leakage was used to detect neuronal damage, formation of reactive oxygen species was determined by using fluorescent probe DCFH-DA. Hoechst 33,342 staining and TUNEL staining were used to determine the cell apoptosis. JC-1 was used to evaluate loss of mitochondrial membrane potential (MMP). The fluorescence intensity of [Ca2+]i in hippocampal neurons was determined by laser scanning confocal microscopy. The expression of various apoptotic markers such as TLR4, IκB, IL-6 and NF-κB were investigated by RT-PCR and western blot analysis. Results from each approach demonstrated that LBP increased the cell abilities and decreased the cell morphologic impairment. Furthermore, LBP increased MMP but inhibited [Ca2+]i elevation and significantly suppressed overexpression of NF-κB, IL-6 TLR4 and increased IκB expression.