目的 探讨槲皮黄酮对β-淀粉样蛋白 (Aβ) 诱导小神经胶质细胞 (BV-2) 损伤的保护作用及其作用机制.方法体外培养BV-2 细胞, 利用Aβ 诱导BV-2 细胞发生损伤;将低 (10 μg/mL) 、中 (20 μg/mL) 、高 (40 μg/mL) 3 种浓度槲皮黄酮对细胞进行处理, 共24 h, 采用CCK8 实验对BV-2 细胞的增殖情况进行评价, 应用ELISA 试剂盒对细胞培养基上清中炎症因子IL-6、TNF-α 的表达水平进行分析, 采用免疫印迹技术分析β-分泌酶 (BACE) 、早老素 (PS1) 、呆蛋白 (NCT) 蛋白表达水平, 并对脑啡肽酶 (NEP) 、胰岛素降解酶 (IDE) 表达水平进行检测.结果 采用Aβ 诱导可较好地构建BV-2 细胞损伤模型, 经过低、中、高3 种剂量的槲皮黄酮处理后, BV-2 细胞的相对存活率较模型组显著增加 (P＜0. 05); 药物处理组细胞培养基上清中IL-6、TNF-α 表达水平低于模型组 (P＜0. 05); Western blot 结果显示, 槲皮黄酮组BACE、PS1、NCT 蛋白表达水平较模型组降低 (P ＜0. 05);槲皮黄酮可以促进Aβ 消化酶NEP、IDE 的表达.结论 槲皮黄酮对Aβ 诱导的BV-2 细胞损伤具有保护作用, 其作用机制可能与抑制Aβ 分泌酶表达和激活Aβ 消化酶表达有关.%Objective To investigate the protective effects of quercetin on the microglia injury induced by amyloid β peptide (Aβ). Methods Microglia (BV-2) cells were cultured in vitro and Aβ was used to induce the injury model of BV-2 cells. Low-, medium- and high-dose (10, 20 and 40 μg/mL) quercetin were used to intervene BV-2 cells for 24 h. The proliferation of BV-2 cells was detected by CCK8 kit, and the expression levels of IL-6 and TNF-α were analyzed by ELISA method. The expression levels of β-secretase 1 (BACE), presenilin-1 (PS1), nicastrin (NCT) and Aβ-digesting enzymes, including neprilysin (NEP) and insulin-degrading enzyme (IDE) were analyzed by Western blot method. Results The microglia injury model was induced by Aβ. The relative survival rates of BV-2 cells in quercetin treatment groups were higher than those of model group (P＜0. 05), while the expression levels of inflammatory cytokines IL-6 and TNF-α were lower (P＜0. 05). The results of Western Blot showed that the expression levels of BACE, PS1 and NCT in quercetin treatment groups were lower than those of model group (P＜0. 05). Quercetin could improve the expression levels of NEP and IDE (P＜0. 05). Conclusion Quercetin can inhibit the BV-2 cells injury induced by Aβ via inhibiting the expression of Aβ-secretase and promoting the activation of Aβ-digesting enzymes.
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