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褪黑素对异丙肾上腺素诱导大鼠tau蛋白过度磷酸化的预防作用

王小川, 张菁, 余娴, 韩柳, 周震涛, 张瑶, 王建枝

华中科技大学同济医学院病理生理系.湖北，武汉 430030

摘要

异常过度磷酸化的微管相关蛋白tau是阿尔茨海默病(AD)患者大脑中神经原纤维缠结的主要组成部分。迄今为止，尚无有效的措施阻止tau蛋白的过度磷酸化。为探讨褪黑素（melatonin，Mel）对AD样tau蛋白过度磷酸化的预防作用，我们以β受体激动剂异丙肾上腺素（isoproterenol，IP）来复制AD样tau蛋白过度磷酸化的动物模型，并以褪黑素作为保护组药物，在大鼠双侧海马注射IP 前，于腹腔连续注射5天。应用磷酸化位点特异性抗体(PHF-1和Tau-1)作免疫印迹和免疫组织化学检测tau蛋白的磷酸化水平，并用非磷酸化依赖的总tau蛋白抗体(111e)进行标准化。免疫印迹结果显示：在IP注射48小时后，tau蛋白在PHF-1表位的免疫反应显著增强，在Tau -1表位显著减弱，表明tau蛋白在Ser396/Ser404 (PHF-1)和 Ser199/Ser202 (Tau-1)位点有过度磷酸化。免疫组织化学染色结果与免疫印迹结果相似，主要检测到在大鼠海马CA3区的神经纤维有tau蛋白过度磷酸化。褪黑素预处理大鼠可有效地阻止由IP诱导tau蛋白在Tau-1和PHF-1位点的过度磷酸化。该结果提示：褪黑素可预防大鼠脑组织中由异丙肾上腺素引起的AD样tau蛋白的过度磷酸化。

关键词： 阿尔茨海默病; 褪黑素; 反式异丙肾上腺素; tau 蛋白; 异常磷酸化

Prevention of isoproterenol-induced tau hyperphosphorylation by melatonin in the rat

Wang Xiaochuan, Zhang Jing, Yu Xian, Han Liu, Zhou Zhentao, Zhang Yao, Wang Jianzhi

Department of Pathophysiology, Tongji Medical College, Huazhong University of Science and Technology.Wuhan 430030,Hubei

Abstract

Hyperphosphorylated microtubule-associated protein tau is the major protein component of neurofibrillary tangles in the brain of patients with Alzheimer disease (AD). Until now, there is no effective cure to arrest this hyperphosphorylation. The present study was designed to explore the in vivo preventive effect of melatonin on Alzheimer-like tau hyperphosphorylation. Isoproterenol, a β-receptor agonist, was used to induce tau hyperphosphorylation, and for preventive effect of melatonin, the rats were injected intraperitoneally with melatonin for 5 days before hippocampi infusion of isoproterenol. The level of tau phosphorylation was detected by Western blot and immunohistochemistry using sites specific antibodies (PHF-1 and Tau-1), and it was normalized by non-phosphorylation dependent total tau antibody (111e). The results by Western blot showed that the immunoreaction of tau at PHF-1 epitope was enhanced, and the reaction at Tau-1 epitope was weakened significantly at 48 h after injection of isoproterenol, suggesting hyperphosphorylation of tau at Ser396/Ser404 (PHF-1) and Ser199/Ser202 (Tau-1) sites. Similar results were observed by immunohistochemistry staining, in which hyperphosphorylated tau was mainly detected in mossy fibers of hippocampal CA3 region. Pre-injection of rats with melatonin intraperitoneally arrested effectively the isoproterenol-induced tau hyperphosphorylation at both Tau-1 and PHF-1 sites, implying the preventive effect of melatonin in Alzheimer-like tau hyperphosphorylation.

Key words: Alzheimer disease's;Melatonin;Isoproterenol;Tau;Hyperphosphorylation

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引用本文：

王小川, 张菁, 余娴, 韩柳, 周震涛, 张瑶, 王建枝. 褪黑素对异丙肾上腺素诱导大鼠tau蛋白过度磷酸化的预防作用[J]. 生理学报 2005; 57 (1): .

Wang Xiaochuan, Zhang Jing, Yu Xian, Han Liu, Zhou Zhentao, Zhang Yao, Wang Jianzhi. Prevention of isoproterenol-induced tau hyperphosphorylation by melatonin in the rat. Acta Physiol Sin 2005; 57 (1): (in Chinese with English abstract).