饮食与抗氧化剂──营养干预研究

Diet and Antioxidant-a Nutritional Intervention Study

流行病学研究表明多吃蔬菜可以减少癌症的危险性。抗氧化剂已被认为是主要的抗癌系统。谷胱甘肽转移酶（GSTs）是抗氧化损伤抵抗系统的组成之一，它可被抗氧化剂和氧化压力通过抗氧化反应因子诱导。为了进一步研究蔬菜的作用和其抗癌机制，在本干预试验中，8个研究对象接受正常饮食以外的附加蔬菜。用HPLC法测定血清维生素A醇和a-生育酚的含量，用反转录一聚合酶链式反应（RT－PCR）技术测定淋巴细胞GSTЛ基因的表达。结果表明，增加蔬菜摄入前后，血清维生素A醇和a一生育酚含量没有显著性差异。但增加蔬菜摄入后，5个研究对象中，4人淋巴细胞GSTЛmRNA水平升高。结果提示：在蔬菜中，除维生素A和维生素E以外的其他的抗氧化剂可能诱导了GSTЛ基因的转录。本试验为以后的大规模人群干预研究奠定了方法学基础。

It has been implicated that high vegetable intake is associated with a decreased risk forvarious forms of cancer in epidemiological studies. A major defense system against cancer has shown to beantioxidants. Glutathione S- transferases (GSTs), one of the major defense ststems against oxidativedamage, can be induced by antioxidant and addition of vegetables to their normal diet. Serum retinol anda - tocopherol were determined by HPLC and the gene expression of GSTЛ in lymphocytes was measuredby reverse transcription - Polymerase chain reaction (RT-PCR) techniques. The results showed thatthere was on significant difference in the levels of serum retinol and a - tocopherol before and after theaddition of vegetables. GSTЛ mRNA levels in lymphocytes were higher in four out of five subjects afteraddition of vegetables. The results suggested that it might be other antioxidants than vitamin A and E inthe vegetables that induced the gene transcription of GSTЛ.