β淀粉样蛋白对神经元上烟碱型乙酰胆碱受体β2亚单位表达的影响

目的观察β淀粉样蛋白25-35片断(A2β5-35)对海马神经元的损伤,及神经元上烟碱型乙酰胆碱受体β2亚单位(β2-nAChR)表达的变化。方法实验组用不同浓度(1、5、10、20μmol/L)的Aβ25-35诱导原代培养的海马神经元损伤,用倒置显微镜及四甲基偶氮唑盐微量酶反应比色法观察各组的神经元形态及存活的变化;用免疫荧光法观察神经元上标记的β2-nAChR的表达的变化,并用激光扫描共聚焦显微镜行半定量。结果各实验组的神经元形态上有不同程度地受损表现;各实验组的吸光度(A)值较不加A2β5-35的对照组减小,神经元上标记的β2-nAChR的平均相对荧光强度较对照组减小。结论A2β5-35可引起海马神经元损伤,并减少海马神经元上β2-nAChR表达量,Aβ25-35浓度越高,β2-nAChR表达量越低。

The effect of beta-amyloid peptide on the expression of beta2-nicotinic acetylcholine receptors in hippocampus neurons

Objective To investigate the impairment of hippocampus neurons induced by beta-amyloid 25-35 fragment(Aβ_(25-35)) and the effect of Aβ_(25-35) on the expression of beta2 nicotinic acetylcholine receptor((β2-nAChRs)).Methods In treated groups,the primary cultured hippocampus neurons were exposed to different concentrations of Aβ_(25-35)(1 μmol/L,5 μmol/L,10 μmol/L and 20 μmol/L).The morphological changes of the impaired neurons were observed by inverted microscopy and MTT assay was used to measure the changes of the cell viability.The β2-nAChRs expression in the impaired neurons was observed by immunofluorescence staining.Confocal laser scanning microscopy(CLSM) was used to measure the fluorescence intensity of β2-nAChRs in the hippocampus neurons.Results The cultured neurons had different degrees of impairment in all treated groups.Exposure of neurons to various concentrations of Aβ_(25-35) evoked a decrease in absorbance(A) value of MTT(P<(0.05)).Immunofluorescence staining indicated that the β2-nAChRs expression in the impaired hippocampus neurons decreased significantly and CLSM indicated that the fluorescence intensity of β2-nAChRs in the neurons exposed to Aβ_(25-35) was lower than that in the control without Aβ_(25-35).Conclusion Aβ_(2535) led to the significant morphological changes of the hippocampus neurons and the expression of β2-nAChRs in the impaired neurons decreased with increasing concentration of Aβ_(25-35).