Aβ1-42诱导下大鼠海马细胞胰岛素受体表达的变化

Abnormal expression of insulin receptor induced by Aβ1-42 in rat hippocampus neuron

目的 检测大鼠海马细胞在Aβ1-42诱导下胰岛素受体表达水平的变化,从而在受体水平探讨中枢胰岛素信号紊乩及阿尔茨海默病发病的分子机制.方法 体外培养原代海马神经细胞,经不同浓度Aβ1-42处理,流式细胞术检测细胞凋亡,实时定量PCR和Western印迹法检测胰岛素受体的表达.结果 原代培养的细胞在第7天时发育成熟,鉴定为海马神经细胞;经Aβ1-42（0～150μmol/L）处理后,30 μmol/L以上处理组的早期凋亡率（32.4%,36.1%,51.0%,53.6%）较对照组（13.4%）呈浓度依赖型增高.PCR结果显示,30 μmol/L（2.56±0.19）和60 μmol/L（3.44±0.23）处理组的胰岛素受体水平较对照组（设为1）明显增高（P＜0.01）,100 μmol/L组（0.74±0.15）则较对照组降低（P＜0.01）.Western结果与PCR结果趋势相同,30和60 μmol/L处理组的蛋白水平为1.27±0.13,1.82±0.10（P＜0.01）,100 μmol/L组为0.82±0.08（P＜0.05）.结论 Aβ1-42诱导大鼠海马细胞胰岛素受体的表达发生改变,致使其出现功能缺陷,提示可能为中枢胰岛素抵抗的原因.关键词：阿尔茨海默病;海马;胰岛素受体;

Objective To detect the expression change of insulin receptor under the induction of Aβ1-42 in rat hippocampus neuron and thus from the receptor level explore the disorder of central nervous insulin signaling and molecular mechanism of Alzheimer＇s disease. Methods Cultured primary hippocampus neuron was treated with different concentrations of Aβ1-42. Apoptosis was detected by flow cytometry. And real-time quantitative PCR（polymerase chain reaction）and Western blot were used to detect the expression of insulin receptor. Results Primary cultured cells, mature at Day 7, were identified as hippocampal cells.After the treatment with different concentrations of Aβ1-42（0 - 150 μmol/L）, the ≥ 30 μmol/L treatment groups had greater early apoptosis rates（32.4 %, 36.1%, 51.0%, 53.6%）than that in the control group （13.4%）in a concentration - dependent fashion. The PCR results showed that the levels of insulin receptor gene were significantly higher in 30（2.56 ± 0. 19）and 60 μmol/L（3.44 ± 0.23）treatment groups than that the control group（regarded as 1）（P 〈 0. 01）while the 100μmol/L group（0.74 ± 0. 15）was significantly lower than the control group（P 〈 0. 01）. And the results of Western blot had the same trend with those of PCR. The 30 and 60 μmol/L protein level of the treatment groups were 1.27 ±0. 13, 1.82 ± 0.10（P〈0.01）and 100μmol/L group was 0.82 ±0.08（P〈0.05）. Conclusions Aβ1-42 induces an altered expression of insulin receptors in rat hippocampus cells and results in its functional defects. It may cause insulin resistance in center nervous system.