β-淀粉样蛋白诱导大鼠海马神经元凋亡及海马亲环素A表达的变化

Amyioid beta-protein induces apoptosis of neurons in rat hippocampus and expression changes of cyclophilin A in these neurons

目的探讨Aβ25-35对大鼠海马神经元的损伤及对亲环素A（CyPA）表达的影响。方法健康Wister大鼠60只按照随机数字表法分为实验组（n=30）和对照组（n=30），实验组大鼠采用Aβ25-35注射人双侧海马制造阿尔茨海默病的动物模型，对照组大鼠同样位置注射人等量生理盐水。HE染色观察2组大鼠海马CA1区神经元形态，TUNEL染色检测细胞凋亡，RT—PCR检测CVPAmRNA的表达，Westernblotting检测CvPA蛋白的表达。结果实验组大鼠海马CA1区神经元遭到破坏，细胞凋亡增加，数量减少，且随时间延长细胞凋亡情况进一步加重，造模后1d、7d、14d较对照组比较差异均有统计学意义（P〈0．05）。实验组大鼠海马组织CVPAmRNA和CVPA蛋白表达量随时间呈现出先增长后降低的趋势，1d、7d时明显高于对照组，差异均有统计学意义（P〈0．051。14d时明显低于对照组大鼠，其中CyPA蛋白的差异具有统计学意义（P〈0．05）。结论Aβ25-35通过加重大鼠海马神经元凋亡诱发神经毒性作用，CyPA表达的增加可能是一种内源性保护因素。

Objective To explore the neuron injury in rat hippocampus induced by Aβ25-35 and the cyclophilin A （CyPA） expression changes in these neurons. Methods Sixty healthy Wister rats were equally randomized into experimental group and control group （n=30）; AD rat models in the experimental group were established by injection of Aβ25-35 into the bilateral hippocampus of rats, and rats of the control group were received NS injection. The morphological features of neurons in the CA1 area of hippocampus were observed by HE staining; the neuron apoptosis was determined with TUNEL staining; the mRNA and protein expressions of CyPA were detected by PT-PCR and Western blotting, respectively. Results Aβ25-35 caused damage and apoptosis of neurons in the CA1 area of hippocampus; with time being prolonged, the cell injury aggravated and apoptosis increased in the CA1 area of hippocampus; significant differences were noted as compared with those in control group 1, 7 and 14 d after the inducement （P〈0.05）. After injection ofAβ25-35 into the hippocampus of rat, the mRNA and protein expressions of CyPA were obviously changed： in early stage, the expressions increased, and then, the expressions decreased gradually; significant differences were noted as compared with those in control group 1 and 7 d after the inducement （P〈0.05）; the protein expression of CyPA in the experimental group 14 d after the inducement was significantly decreased as compared with that in the control group （P〈 0.05）. Conclusion Aβ25-35 plays a neurotoxicity role through aggravating the apoptosis of neurons; and the increment of CyPA expressions maybe play an endogenously protective role in these damage.