甘草苷对原代海马神经细胞的保护和营养作用

目的:研究甘草苷(liquiritin,LQ)对β-淀粉样蛋白(Aβ_25～35)所致大鼠原代神经细胞损伤的保护作用和营养作用。方法:采用大鼠原代海马神经元Aβ_25～35损伤模型,四甲基偶氮唑盐(MTT)法测定细胞活力、流式细胞术检测神经细胞凋亡、荧光探针法检测细胞内钙离子浓度,考察LQ神经保护作用;通过考察LQ诱导海马神经元轴突延长的作用和流式细胞术检测其对海马神经干细胞分化为胆碱能神经元作用观察其神经营养作用。结果:10μmol.L^-1Aβ_25～35显著降低细胞的存活率;明显升高细胞内钙离子水平;诱导细胞凋亡发生,凋亡率达28%。预先给预0.1,1,10μmol.L^-1浓度的LQ处理细胞6 h,可显著抑制Aβ_25～35导致的细胞死亡,能够明显降低Aβ_25～35导致的细胞内钙离子浓度升高,流式细胞检测凋亡率分别降低到10%,15%,22%,提示LQ能够拮抗Aβ_25～35导致的细胞凋亡。LQ能够显著增加神经生长因子(NGF)介导的海马神经元轴突延长,特异性的促分裂原活化蛋白激酶(MAPK)抑制剂能够部分阻断该作用。另外,LQ可以诱导神经干细胞体外定向分化为胆碱能神经元。结论:甘草苷对Aβ_25～35导致的大鼠原代神经细胞损伤具有神经保护作用,同时甘草苷对原代海马神经元有营养作用。

Neuroprotection and neurontrophism effects of liquiritin on primary cultured hippocampal cells

OBJECTIVE: To observe the neuroprotective and neurotrophic effects ofliquiritin (LQ) on rats primary cultured hippocampal neuronal damage induced by Abeta25-35. METHOD: The 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. RESULT: Treatment 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. CONCLUSION: These 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.