AIM: To observe the effect of salvianolic acid-B (SalB)on amyloid beta-protein (A-beta) fibril formation and its toxicity towards PC12 cells. METHODS: A-beta (1 -40) was incubated with or without SalB at 25 ℃ for 30h, 48 h, and 100 h. Fibril formation was then viewed under an electron microscope. Toxicity of the A-beta (1rn?40) towards PC12 cells was measured with 3-[ 4, 5-dimethylthiazol-2-yl ]-2,5-diphenyltetrazolium bromide (MTT). A-beta (25 - 35) was aged by incubating at 25? for 7 d, then the peptide was incubated with PC12cells with or without SalB. Toxicity of A-beta (25 -35) towards PC12 cells was observed with MTT. RESULTS: Following incubation at 25 ? for 30 h, A-beta (1 -40) (100 mg/L) aggregated and formed fibrils.SalB 10 - 100 nmol/L completely prevented the fibril formation within 30 h. Extension of amyloid fibrils increased with prolonging the incubation time. SalB inhibited the fibril formation process during this period. In the MTT assay A-beta (1 -40) incubated with SalB manifested significantly lower toxicity to PC12 cells compared with that without SalB. Besides, SalB 1 祄ol/Lsignificantly attenuated the toxicity of aged A-bera (25-35) to PC12 cells. CONCLUSION: SalB could inhibit A-beta aggregation and fibril formation, as well as directly inhibit the cellular toxicity of aged A-beta towards PC12 cells.%目的：观察丹酚酸B对淀粉样β蛋白的纤维形成及其细胞毒作用的影响.方法：将不同浓度丹酚酸B与淀粉样β蛋白(1-4)在25℃共同孵育，于不同时间取样品电镜观察纤维形成.用MTT法观察此不同时间点淀粉样β蛋白(1-40)对PC12细胞的毒性作用.另将淀粉样β蛋白(25-35)预先老化7 d，用rnrnMTT法观察此老化蛋白对PC12细胞的毒性及丹酚酸B的作用.结果：丹酚酸B 10-100 nmol/L可以完全抑制淀粉样β蛋白(1-40)25℃放置30 h的纤维形成，对淀粉样β蛋白(1-40)25℃放置48及100 h的纤维形成也有明显抑制作用.MTT法显示，经与丹酚酸B共同孵育的淀粉样β蛋白(1-40)明显较未与丹酚酸B孵育的淀粉样β蛋白对PC12细胞的毒性小.丹酚酸B 1 μmol/L可明显抑制预先老化的淀粉样β蛋白(25-35)对PC12细胞的毒性作用.结论：丹酚酸B可抑制淀粉样β蛋白的老化及纤维形成，同时可直接抑制老化淀粉样β蛋白对PC12细胞的毒性作用.
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