目的 考察小檗碱对Aβ_25-35损伤的神经元的保护作用，并初步探讨其机制。方法 40 μg/mL Aβ_25-35作用原代培养大鼠脑皮层神经元36 h，复制阿尔茨海默病（Alzheimer’s disease，AD）细胞模型，同时加入小檗碱进行干预，实验分为对照组、模型组、0.5 μmol/L小檗碱组，2 μmol/L小檗碱组。通过Hoechst33258染色观察神经元凋亡形态；Annexin V-FITC/PI双标流式细胞术检测早期凋亡情况；Western blotting检测活化的Caspase-3蛋白表达，实时荧光定量RT-PCR检测型雷帕霉素靶（target of rapamycin，mTOR）相关基因表达。结果 与对照组比较，AD细胞模型神经元凋亡明显增加。2 μmol/L小檗碱能显著减少Aβ损伤神经元早期凋亡（P＜0.05），0.5、2 μmol/L小檗碱均能抑制异常活化的Caspase-3蛋白表达。0.5、2 μmol/L小檗碱显著下调了AD模型异常活化的mTOR mRNA和下游底物核糖体S6蛋白激酶（S6kinase，S6K）P70S6K mRNA的表达（P＜0.05、0.01），同时显著上调了AD细胞模型真核细胞始动因子4E结合蛋白1（4E binding protein，4EBP1）mRNA的表达（P＜0.01）。结论 小檗碱对Aβ_25-35损伤的原代培养大鼠皮层神经元具有一定神经保护作用，其保护作用可能是通过抑制mTOR途径实现的。

Objective To observe the protective effect of berberin on the cortical neurons of rat injured by Aβ_25-35 and investigate its mechamism. Methods Aβ_25-35 was used to treat the cortical neurons of primary culture rat, at the final concentration of 40 μg/mL for 36 h, Alzheimer’s disease (AD) model was reproduced, and then interferred with berberin together. The experiments were divided into control, model, 0.5 μmol/L berberin, and 2 μmol/L berberin groups. Hoechst33258 stain assay was used to observe the morphological change, Annexin V-FITC/PI double stain flow cytometry assay was used to examine the early neural apoptisis; Western blotting assay was used to observe the activated Caspase-3 protien expression; and RT-PCR assay was used to investigate the mRNA expression of target of Rapamycin (mTOR) related genes. Results Neural apoptosis of AD model significantly increased when treated with 40 μg/mL Aβ_25-35 for 36 h compared with the control group (P<0.01). Following 2 μmol/L berberin treatment, the percentage of Aβ_25-35-induced cell apoptosis significantly decreased (P<0.05) compared with the model group. Berberin (0.5 and 2 μmol/mL) inhibited Aβ_25-35-induced abnormal activated Caspase-3 expression, down-regulated the expression of abnormal activated mTOR mRNA and S6kinase P70S6K mRNA (P<0.05, 0.01), and up-regulated the expression of 4E binding protein (4EBP1) mRNA of AD model (P<0.01). Conclusion Berberin exhibits the protective effects against Aβ_25-35-induced toxicity in cortical neurons of primary cultured rat, which maybe relates with the inhibition of mTOR signal pathway.

教育部科学技术研究重点项目（208009）；高等学校博士学科点专项科研基金（20101210110001）