Augustyniak Agnieszka, Waszkiewicz Ewa, Skrzydlewska Elzbieta
Department of Analytical Chemistry, Medical University of Białystok, Białystok, Poland.
Nutrition. 2005 Sep;21(9):925-32. doi: 10.1016/j.nut.2005.01.006.
The present study investigated the influence of green tea as a source of water-soluble antioxidants on the liver antioxidant potential of different aged rats chronically intoxicated with ethanol.
Rats (2, 12, and 24 mo old) were fed for 5 wk on a control or an ethanol Lieber-DeCarli diet with and without green tea (7 g/L). The activity and level of enzymatic and non-enzymatic antioxidants and the level of markers of protein and lipid oxidation in the liver of rats were examined.
The activities of superoxide dismutase and catalase and levels of vitamins C, E, A, and beta-carotene were significantly decreased, whereas activities of glutathione peroxidase and glutathione reductase and the level of reduced glutathione significantly increased during aging. The ethanol diet caused a significant decrease in activity of antioxidant enzymes and in the level of non-enzymatic antioxidants tested. Administration of green tea to ethanol-treated rats of different ages partly normalized the activity of enzymes and the level of non-enzymatic antioxidants. Changes in antioxidant ability observed during aging were accompanied by increased levels of markers of lipid and protein modifications that also were intensified by ethanol. Green tea caused a decrease in lipid and protein oxidation in aged and ethanol-treated rats. The protective effect of green tea was confirmed by the significantly lower activity of biomarkers of liver damage (alanine and aspartate aminotransferases) in the serum of rats that received green tea with ethanol compared with rats from the control ethanol group.
The use of green tea appears to be beneficial to rat liver by decreasing oxidative stress caused by ethanol and/or aging.
本研究调查了作为水溶性抗氧化剂来源的绿茶对长期乙醇中毒的不同年龄大鼠肝脏抗氧化潜力的影响。
将大鼠（2、12和24月龄）分为对照组和乙醇组，每组再分为添加绿茶（7 g/L）和不添加绿茶的亚组，分别给予Lieber-DeCarli饮食5周。检测大鼠肝脏中酶促和非酶促抗氧化剂的活性及水平，以及蛋白质和脂质氧化标记物的水平。
随着年龄增长，超氧化物歧化酶和过氧化氢酶的活性以及维生素C、E、A和β-胡萝卜素的水平显著降低，而谷胱甘肽过氧化物酶和谷胱甘肽还原酶的活性以及还原型谷胱甘肽的水平显著升高。乙醇饮食导致所检测的抗氧化酶活性和非酶促抗氧化剂水平显著降低。给不同年龄的乙醇处理大鼠饮用绿茶，部分使酶活性和非酶促抗氧化剂水平恢复正常。衰老过程中观察到的抗氧化能力变化伴随着脂质和蛋白质修饰标记物水平的增加，乙醇也加剧了这种增加。绿茶使老年和乙醇处理大鼠的脂质和蛋白质氧化减少。与对照组乙醇组大鼠相比，饮用绿茶加乙醇的大鼠血清中肝损伤生物标志物（丙氨酸和天冬氨酸转氨酶）的活性显著降低，证实了绿茶的保护作用。
饮用绿茶似乎对大鼠肝脏有益，可减少乙醇和/或衰老引起的氧化应激。
