英语科普小知识 减少热量摄入可延缓神经细胞损耗

海量资料下载 免费学习英语 www.englishvip.com/xinlw.htm （申请网址） Activating an enzyme known to play a role in the anti-aging benefits of calorie restriction delays the loss of brain cells and preserves cognitive function in mice, according to a study published in the May 22 issue of The Journal of Neuroscience. The findings could one day guide researchers to discover drug alternatives that slow the progress of age-associated impairments in the brain. Previous studies have shown that reducing calorie consumption extends the lifespan of a variety of species and decreases the brain changes that often accompany aging and neurodegenerative diseases such as Alzheimer's. There is also evidence that caloric restriction activates an enzyme called Sirtuin 1 (SIRT1), which studies suggest offers some protection against age-associated impairments（损害） in the brain.   In the current study, Li-Huei Tsai, PhD, Johannes Gräff, PhD, and others at the Picower Institute For Learning and Memory, Massachusetts Institute of Technology, and Howard Hughes Medical Institute, tested whether reducing caloric intake would delay the onset of nerve cell loss that is common in neurodegenerative disease, and if so, whether SIRT1 activation was driving this effect. The group not only confirmed that caloric restriction delays nerve cell loss, but also found that a drug that activates SIRT1 produces the same effects.   "There has been great interest in finding compounds that mimic the benefits of caloric restriction that could be used to delay the onset of age-associated problems and/or diseases," said Luigi Puglielli, MD, PhD, who studies aging at the University of Wisconsin, Madison, and was not involved in this study. "If proven safe for humans, this study suggests such a drug could be used as a preventive tool to delay the onset of neurodegeneration associated with several diseases that affect the aging brain," Puglielli added.   In the study, Tsai's team first decreased by 30 percent the normal diets of mice genetically engineered to rapidly undergo changes in the brain associated with neurodegeneration. Following three months on the diet, the mice completed several learning and memory tests. "We not only observed a delay in the onset of neurodegeneration in the calorie-restricted mice, but the animals were spared the learning and memory deficits of mice that did not consume reduced-calorie diets," Tsai explained.   Curious if they could recreate the benefits of caloric restriction without changing the animals' diets, the scientists gave a separate group of mice a drug that activates SIRT1. Similar to what the researchers found in the mice exposed to reduced-calorie diets, the mice that received the drug had less cell loss and better cellular connectivity than the mice that did not receive the drug. Additionally, the mice that received the drug treatment performed as well as normal mice in learning and memory tests.   "The question now is whether this type of treatment will work in other animal models, whether it's safe for use over time, and whether it only temporarily slows down the progression of neurodegeneration or stops it altogether," Tsai said. 激活已知的酶发挥作用的热量限制延缓脑细胞损失的抗衰老的好处，并保留小鼠的认知功能，根据5月22日发行的“神经科学杂志发表的一项研究。这一发现可能引导研究人员发现药物的替代品，进度慢的年龄相关的大脑中的障碍。以前的研究已经表明，减少热量消耗，延长寿命的各种物种和减少大脑的变化，往往伴随着衰老和神经退行性疾病，如阿尔茨海默氏症。也有证据表明，限制热量摄入激活酶的Sirtuin 1（SIRT1）的研究表明，在大脑中对年龄相关的减值（损害）提供了一些保护。   在目前的研究中，锂辉仔，博士，约翰内斯·格拉夫博士，和其他皮考尔学习和记忆研究所，麻省理工学院，和霍华德休斯医学研究所，测试，减少热量摄入是否会延缓神经细胞的损失是常见的神经退行性疾病，如果是这样，SIRT1激活是否是驱动这样的效果。组不仅证实，限制热量延迟神经细胞损失，而且还发现，一种药物，激活SIRT1产生同样的效果。   “我们一直在寻找模仿热量限制的好处，可以用来延缓发病年龄相关的问题和/或疾病的化合物的极大兴趣，说：”Luigi Puglielli的，博士，大学研究老化威斯康星大学麦迪逊分校，并没有参与这项研究。如果证明对人类安全，这项研究表明这样的药物可以作为一种预防工具延缓发病的神经退行性疾病相关的一些疾病，影响大脑老化，“Puglielli。   仔的团队在研究中，首先由30％下降遗传工程小鼠的正常饮食与神经退行性疾病相关的大脑迅速发生变化。经过三个月的饮食，小鼠完成一些学习和记忆测试。“我们不仅观察到了在限制热量的老鼠的神经退行性疾病的发病延迟，但小鼠的学习记忆障碍，没有消耗减少热量的饮食，蔡解释说：”动物也难幸免。   好奇，如果他们可以重建而不改变动物的饮食，限制热量的好处，科学家给一组独立的小鼠药物激活SIRT1。研究人员发现，在小鼠暴露于低热量饮食相似，老鼠接受药物有比没有接受药物治疗的老鼠的细胞丢失和更好的蜂窝连接。此外，老鼠接受药物治疗的进行，以及正常小鼠学习和记忆测试。   “现在的问题是这种类型的治疗是否会在其他动物模型中，随着时间的推移使用是否安全，是否只是暂时减缓神经退行性疾病的进展或完全停止工作，”她说。 “成千上万人疯狂下载。。。。。。 更多价值连城的绝密英语学习资料， 洛基内部秘密英语，技巧，策略 请在 网上 申请报名” 洛基国际英语 竭诚为您服务