五味子乙素抑制M146L细胞Aβ42生成的机制研究

目的研究五味子乙素抑制M146L细胞Aβ₄₂生成的机制。方法体外培养高效表达Aβ42的M146L细胞株，分别加入不同浓度的五味子乙素(1.67，5.00和15.00 μg·mL^-1)、 β分泌酶抑制剂(S4562，100.00 μg·mL^-1)和γ分泌酶抑制剂(S2188，13.68 μg·mL^-1)。用CCK-8(cell counting kit-8)比色法检测不同处理对M146L细胞活性的影响；用ELISA法测定M146L细胞所分泌的Aβ₄₂的变化；用Western blotting检测APP的β分泌酶剪切产物C99蛋白的含量变化，结合用β和γ分泌酶活性试剂盒，检测五味子乙素对这两种酶活性的影响。结果不同处理因素对M146L细胞的存活率均无影响，不具有细胞毒作用。中、高剂量的五味子乙素均不同程度地抑制M146L细胞分泌Aβ₄₂及γ分泌酶的活性，但都不改变M146L细胞C99蛋白的含量及β分泌酶的活性。结论五味子乙素可抑制γ分泌酶活性，其降低Aβ₄₂生成是通过抑制γ分泌酶的活性来实现的。

γ-Schisandrin inhibits production of amyloid β-protein 42 in M146L cells

AimTo investigate the inhibition of amyloid β-protein 42 (Aβ₄₂) production in M146L cells by γ-schisandrin. MethodsM146L cells which can produce considerable Aβ₄₂in vitro were treated with ₄₂-schisandrin (1.67, 5.00 and 15.00 μg·mL^-1), β-secretase inhibitor (S4562, 100.00 μg·mL^-1) and ₄₂-secretase inhibitor (S2188, 13.68 μg·mL^-1), separately. Cell counting kit-8 (CCK-8) was used to assess cell viability. Enzyme-linked immunosorbent assay (ELISA) was carried out to determine the amount of Aβ₄₂. Western blotting was used to examine C99, an intermediary product of APP cleaved by β-secretase. β-Secretase and ₄₂-secretase activities were assayed by commercial kits. Results The CCK-8 assay indicated that different concentrations of γ-schisandrin had no neurotoxicity on the cultured M146L. And the ELISA test showed that the amount of Aβ₄₂secreted by M146L cells treated with γ-schisandrin (5.00 and 15.00 μg·mL^-1) decreased obviously as compared with solvent control. The results of Western blotting test indicated that there was no change of C99 contents and β-secretase activity in γ-schisandrin treated cells, while γ-secretase activity decreased obviously. Conclusionγ-Schisandrin inhibited production of Aβ₄₂ in M146L cells through inhibiting γ-secretase.