Catalá Angel
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET, La Plata, Argentina.
Curr Mol Med. 2007 Nov;7(7):638-49. doi: 10.2174/156652407782564444.
This paper reviews recent data relevant to the antioxidant effects of melatonin with special emphasis on the changes produced in polyunsaturated fatty acids located in the phospholipids of biological membranes. The onset of lipid peroxidation within cellular membranes is associated with changes in their physicochemical properties and with the impairment of protein functions located in the membrane environment. All cellular membranes are especially vulnerable to oxidation due to their high concentration of polyunsaturated fatty acids. These processes combine to produce changes in the biophysical properties of membranes that can have profound effects on the activity of membrane-bound proteins. This review deals with aspects for lipid peroxidation of biological membranes in general, but with some emphasis on changes of polyunsaturated fatty acids, which arise most prominently in membranes and have been studied extensively in our laboratory. The article provides current information on the effect of melatonin on biological membranes, changes in fluidity, fatty acid composition and lipid-protein modifications during the lipid peroxidation process of photoreceptor membranes and modulation of gene expression by the hormone and its preventive effects on adriamycin-induced lipid peroxidation in rat liver. Simple model systems have often been employed to measure the activity of antioxidants. Although such studies are important and essential to understand the mechanisms and kinetics of antioxidant action, it should be noted that the results of simple in vitro model experiments cannot be directly extrapolated to in vivo systems. For example, the antioxidant capacity of melatonin, one of the important physiological lipophilic antioxidants, in solution of pure triglycerides enriched in omega-3 polyunsaturated fatty acids is considerably different from that in subcellular membranes.
本文综述了与褪黑素抗氧化作用相关的最新数据，特别强调了生物膜磷脂中多不饱和脂肪酸所产生的变化。细胞膜内脂质过氧化的发生与膜的物理化学性质变化以及膜环境中蛋白质功能的受损有关。所有细胞膜因其高浓度的多不饱和脂肪酸而特别容易受到氧化。这些过程共同导致膜的生物物理性质发生变化，进而对膜结合蛋白的活性产生深远影响。本综述总体上探讨了生物膜脂质过氧化的各个方面，但特别强调了多不饱和脂肪酸的变化，这些变化在膜中最为显著，并且在我们实验室中已得到广泛研究。本文提供了关于褪黑素对生物膜的影响、光感受器膜脂质过氧化过程中流动性、脂肪酸组成和脂质 - 蛋白质修饰的变化，以及该激素对基因表达的调节及其对阿霉素诱导的大鼠肝脏脂质过氧化的预防作用的当前信息。简单的模型系统常常被用于测量抗氧化剂的活性。虽然此类研究对于理解抗氧化作用的机制和动力学很重要且必不可少，但应注意，简单的体外模型实验结果不能直接外推至体内系统。例如，重要的生理性亲脂性抗氧化剂之一褪黑素在富含ω - 3多不饱和脂肪酸的纯甘油三酯溶液中的抗氧化能力与在亚细胞膜中的抗氧化能力有很大差异。
