白细胞介素-1对β淀粉样蛋白胞毒及基因表达的调节作用

Relationship between interleukin-1 and β-amyloid protein in the brain tissue of patients with Alzheimer's disease

目的:研究β淀粉样蛋白(β-amyloidprotein,Aβ)的神经元毒性作用及白细胞介素1(interleukin-1β,IL-1β)对神经细胞β淀粉样蛋白前体(β-amyloidprecursorprotein,APP)基因表达以及对Aβ细胞毒性的调节作用。方法:以PC12细胞作为体外神经细胞模型,应用四唑盐(MTT)法检测Aβ,IL-1β对细胞活性的影响,应用RT-PCR法半定量分析IL-1β对APP基因表达的影响。结果:Aβ具有直接的神经细胞毒作用,与浓度以及聚集状态相关,以20μmol/L孵育3h毒性最大(q=5.62,P<0.01),而孵育7d者几乎没有毒性。IL-1β(浓度为20μg/L)与Aβ25-35(浓度为20μmol/L孵育3h)共同作用于细胞时,Aβ25-35的细胞毒作用被扩大,细胞活性从36.7%降到了13.2%(q=3.8,P<0.05);当IL-1β(浓度为20μg/L)与Aβ25-35(20μmol/L孵育7d)共同作用时,细胞活性迅速下降,从93%降到了7.7%(q=4.83,P<0.01)。IL-1β可以刺激PC12细胞APP751、770mRNA表达增加,与对照组相比,20μg/L组APPmRNA表达增加约为2倍(q=4.76,P<0.01),此后增加不明显;APPmRNA的表达在IL-1β(20μg/L)刺激6h达高峰,约为对照组的2倍(q=4.92,P<0.01)。结论:Aβ具有直接细胞毒作用,与浓度以及聚集状态相关。IL-1β可以扩大Aβ的细胞毒性作用。IL-1β可以刺激PC12细胞APPmRNA表达增加。

AIM:To study the neurotoxic effect of amyloid β peptide(Aβ) and the acccomodation of interleukin 1β(IL 1β) on the gene expression of β amyloid precursor protein(APP) and Aβcytotoxicity. METHODS:PC12 cells were taken as the nerve cell models in vitro.The effect of Aβand IL 1βon cytoactive was assessed by MTT assay,the effect of IL 1βon the APP gene expression was analyzed semi quantitatively by RT PCR. RESULTS:Aβhad a direct neurotoxic effect,and was correlated with the concentration and aggregation,the maximum cytotoxic effect was found with 3 h incubation in water(20 μmol/L)(q=5.62,P< 0.01),while there was no cytotoxicity when the peptide was incubated for 7 days.The cytotoxicity of Aβ25-35 was expanded and the cytoactivity reduced from 36.7%to 13.2%under the combined effect of IL 1β(20 μg/L) and Aβ25-35 (20 μmol/L,3 h incubation)(q=3.8,P< 0.05).The cytoactivity reduced instantly from 93%to 7.7%under the combined effect of IL 1β(20 μg/L) and Aβ25-35(20 μmol/L,7 d incubation)(q=4.83,P< 0.01).IL 1βcan increase APP751 and mRNA expression,the APP mRNA expression in the 20 μg/L group increased nearly twice as that in the control group(q=4.76,P< 0.01),the increase was not obvious after that;the APP mRNA expression in IL 1β(20 μg/L)reached the peak after 6 h,which was twice as that in the control group(q=4.92,P< 0.01). CONCLUSION:Aβhas a direct neurotoxic effect,and is correlated with the concentration and aggregation.The cytotoxicity can be expanded by IL 1β,it can increase in APP mRNA expression of PC12 cell,and it is dosage and time dependent.