OBJECTIVETo observe the neuroprotective and neurotrophic effects ofliquiritin (LQ) on rats primary cultured hippocampal neuronal damage induced by Abeta25-35.

METHODThe rats hippocampal neuronal damage model by Abeta25-35 was established. The protective effects of LQ to the cells were observed through the MTU assay. The apoptosis of neurons was detected by flow cytometer and the concentration of intracellular calcium by fluorescence probe dying. LQ' s neurotrophic effects were observed through measuring the neurite outgrowth induced by LQ in primary cultured hippocampal neurons and the differentiation of LQ on hippocampal stem cells to cholinergic neurons was assayed by flow cytometry.

RESULTTreatment of the cells with 10 micromol x L(-1) Abeta25-35 could induce a significant decrease of cell viability, enhance the level of intracellular [Ca2+] and increase the percentage of apoptosis to 28%. However, pretreatment with LQ (0.1, 1, and 10 micromol x L(-1)) for 6 hours exhibited cytoprotective effects, inhibited the cells' s death induced by Abeta25-35, prevented the accumulation of [Ca2+], and decreased the apoptosis neurons significantly to 10%, 15% and 9%, which meaned that LQ could antagonize Abeta25-35 induced apoptosis. LQ together with NGF had a dramatic prolonged effect on the neurite of the primary cultured hippocampal neurons, which was blocked by a specific MAPK kinase inhibitor to some extent. In addition, LQ could induce the differentiation of hippocampal stem cells to cholinergic neurons in vitro.

CONCLUSIONThese results demonstrate that LQ has the neuroprotective capacity to cell damage iduced by Abeta25-35 in primary cultured hippocampal neurons, and also has the neurotrophic effects.