Ramaciotti Centre for Gene Function Analysis and Department of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, NSW 2052, Australia.
Free Radic Biol Med. 2010 Jul 15;49(2):237-44. doi: 10.1016/j.freeradbiomed.2010.04.008. Epub 2010 Apr 18.
Reactive oxygen species contribute to cellular ageing and an increased level of oxidative stress is often associated with ageing in many organisms. Supplementation of antioxidants has been advocated to decrease cellular oxidative stress and potentially extend lifespan. A genetically modified K6001 strain of Saccharomyces cerevisiae was employed to determine the effect of several antioxidants, including D-erythroascorbic acid, alpha-tocopherol and coenzyme Q(10) on yeast cell replicative ageing. The replicative lifespan of the K6001 strain was assessed by absorbance change as cells exhibited a linear growth in glucose medium. In this study, water-soluble D-erythroascorbic acid had little effect on cell replicative lifespan. However, supplementation of the growth medium with the lipophilic antioxidants alpha-tocopherol increased oxidative stress and decreased cell lifespan. The use of alpha-tocopherol analogues revealed that the antioxidant activity and the membrane retention ability of alpha-tocopherol were involved in the lifespan reduction effect. Supplementation with either coenzyme Q(10) alone, or in combination with alpha-tocopherol also led to a reduction in yeast replicative lifespan. This study highlights a potential pro-oxidant action of antioxidants.
活性氧自由基会导致细胞衰老,而在许多生物体中,氧化应激水平的增加通常与衰老有关。因此,人们提倡补充抗氧化剂来降低细胞的氧化应激水平,并可能延长寿命。本研究采用经过基因改造的 K6001 酿酒酵母菌株,来确定几种抗氧化剂,包括 D-erythroascorbic 酸、α-生育酚和辅酶 Q(10),对酵母细胞复制衰老的影响。通过细胞在葡萄糖培养基中表现出的线性生长来评估 K6001 菌株的复制寿命,通过吸光度变化进行评估。在本研究中,水溶性 D-erythroascorbic 酸对细胞复制寿命几乎没有影响。然而,向生长培养基中添加亲脂性抗氧化剂 α-生育酚会增加氧化应激并缩短细胞寿命。使用 α-生育酚类似物表明,α-生育酚的抗氧化活性和膜保留能力参与了降低寿命的作用。单独补充辅酶 Q(10)或与 α-生育酚联合补充也会导致酵母复制寿命的缩短。本研究强调了抗氧化剂的潜在促氧化剂作用。