Rao G, Xia E, Nadakavukaren M J, Richardson A
Department of Biological Sciences, Illinois State University, Normal 61761.
J Nutr. 1990 Jun;120(6):602-9. doi: 10.1093/jn/120.6.602.
The effects of aging and dietary restriction on the expression of several enzymes (superoxide dismutase, catalase and glutathione peroxidase) that are involved in free radical detoxification were studied in liver tissue from male Fischer F344 rats. The expression (i.e., activities and mRNA levels) of superoxide dismutase (Cu-Zn) and catalase decreased with age in liver. Dietary restriction (40% restriction of energy intake) increased the activities of superoxide dismutase (24 to 38%) and catalase (64 to 75%) in liver at 21 and 28 mo of age. Glutathione peroxidase activity in liver of diet-restricted rats was significantly higher (37%) at 28 mo of age than that of rats fed ad libitum. The age-related changes in the relative levels of mRNA for superoxide dismutase, catalase and glutathione peroxidase paralleled the changes in the activities of these enzymes in rats fed ad libitum or rats fed the restricted diet. Thus, the changes in the activities of superoxide dismutase, catalase and glutathione peroxidase with age and dietary restriction appear to arise from changes in the levels of mRNAs coding for these enzymes. Free radical damage, as measured by thiobarbituric acid-reactive material and lipofuscin accumulation, was lower in diet-restricted rats than in rats fed ad libitum.
在雄性Fischer F344大鼠的肝脏组织中，研究了衰老和饮食限制对几种参与自由基解毒的酶（超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶）表达的影响。肝脏中超氧化物歧化酶（铜锌）和过氧化氢酶的表达（即活性和mRNA水平）随年龄增长而降低。饮食限制（能量摄入限制40%）在21和28月龄时增加了肝脏中超氧化物歧化酶（24%至38%）和过氧化氢酶（64%至75%）的活性。在28月龄时，饮食限制大鼠肝脏中的谷胱甘肽过氧化物酶活性比自由采食大鼠显著高37%。在自由采食或饮食限制的大鼠中，超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶mRNA相对水平的年龄相关变化与这些酶活性的变化平行。因此，超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶活性随年龄和饮食限制的变化似乎源于编码这些酶的mRNA水平的变化。通过硫代巴比妥酸反应物质和脂褐素积累测量的自由基损伤，在饮食限制大鼠中比自由采食大鼠低。
