胰岛素样生长因子1对β样淀粉蛋白引起的神经元凋亡和tau蛋白磷酸化的作用(英文)  

EFFECTS OF INSULIN-LIKE GROWTH FACTOR 1 ON β-AMYLOID INDUCED NEURON APOPTOSIS AND TAU PHOSPHORYLATION

作　　者：邢长虹[1] 彭英[2] 谢佐平[1] 

机构地区：[1]清华大学生物科学与技术系,北京100084 [2]中国医学科学院与北京协和医科大学药物研究所,北京100050

出　　处：《神经解剖学杂志》2005年第6期569-575,共7页Chinese Journal of Neuroanatomy

摘　　要：本研究的目的是阐明胰岛素样生长因子1(IGF-1)对β样淀粉蛋白(Aβ)引起的神经元凋亡的保护作用,以及tau蛋白磷酸化的作用。用MTT(四甲基偶氮唑盐)方法检测细胞活性,用流式细胞学结合Annexin V-FITC和PI(碘化丙锭)双染的方法检测早期凋亡和晚期凋亡/坏死,用Hoechst 33342染色观察凋亡细胞形态学,用免疫细胞化学的方法检测tau蛋白磷酸化。IGF-1阻止了Aβ25-35引起的培养的大鼠海马神经元的毒性,MTT值显著增加,从54.51%增至61.8%,Hoechst 33342阳性细胞的百分比从30.77%减少到22.81%。Aβ25-35孵育使Annexin V单标记细胞(Annexin V+/PI-)以及Annexin V/PI双标记细胞(An-nexin V+/PI +)的百分比显著增加(分别为3.41%和19.47%),应用100 ng/ml的IGF-1可显著减少Annexin V单标记细胞和Annexin V/PI双标记细胞的百分比分别至2.98%和15.16%。Aβ25-35可增加tau蛋白磷酸化,AT8阳性细胞占41.84%,而IGF-1则可抑制这一效应。我们的结果表明IGF-1可保护神经元,降低Aβ的细胞毒性,减少早期和晚期凋亡/坏死细胞的比例,抑制tau蛋白磷酸化,这可能是IGF-1神经保护作用的细胞机制。The aim of this study is to elucidate the protective and anti-apoptotic effects of insulin-like growth factor 1 （ IGF-1） against β-amyloid （Aβ） and investigate the effect of IGF-1 on Aβ-indueed tau phosphorylation. Cell viahility was measured using the MTF （3-（4, 5-dimethyhhiazolyl-2）-2,5-diphenyhetrazolium bromide） assay, early apoptosis anti late apoptosis/necrosis were analyzed by flow eylometry. using Annexin V-FITC anti propidium iodide （PI） double staining, and morphology was examined by Hoeehst 33342 staining. Tau phosphorylation was detected using AT8 inmunostaining. Preincubation of euhured rat hippocampal neurons with IGF-1 for 24 h prevented cytotoxicity induced by Aβ25-35 for 48 h. The MTF value significantly increased from 54.51% to 61.8% of the control group, and the percentage of Hoechst 33342-positive cells decreased from 30.77% to 22.81%. Incubation with Aβ25-35 for 48 h caused a marked increase in the percentages of Aonexin V-FITC single-labeled cells （ Annexin V ＋/PI-） and Annexin V/PI double-stained cells （Annexin V ＋/PI ＋ ） （3.41% and 19.47% , respectively） , which were significantly decreased by pretreatment with 100ng/ml of IGF-1 for 24 h （ to 2.98% and 15. 16% , respectively）. Aβ25-35 treatment increased tau phosphorylation and AT8 positive cells were 41.84%. This effecl could be inhihited hy different concetrations of IGF-1. Our findings showed that IGF-1 protected against Aβ-induced cytotoxicity, decreased the percentage of early and late apoptosis/necrosis cells, and inhibited tau phosphorylation, which may he the cellular mechanisms for its neuroprotective action.

关 键 词：胰岛素样生长因子1 β样淀粉蛋白 细胞凋亡Tau 流式细胞 ALZHEIMER病 

分 类 号：R749.16[医药卫生—神经病学与精神病学]