MEMELİLERDE ORTALAMA YAŞAM SÜRESİ VE YAŞLANMA SÜRECİNDE SERBEST RADİKALLERİN ROLÜ

Yıl 2007, Cilt: 33 Sayı: 1, 43 - 49, 26.11.2012

Sema Yaralıoğlu Gürgöze Tekin Şahin M. Durak

Öz

ÖZET

Serbest oksijen radikalleri yaşlılığın önemli nedensel ajanları olarak kabul edilmektedirler. Bu derlemede, antioksidan korunma ve yaşam suresi arasındaki ilişki, oksidatif hasardaki azalmanın yaşam süresine etkisi ve serbest radikal hasarı ile yaşlanmada beslenmenin etkileri konuları irdelenmiştir. Serbest radikallerin ana kaynağı moleküler oksijendir. Moleküler oksijenin tek valanslı redüksiyonu (univalent redüksiyonu) superoksit dismutaz anyonları (O₂.-) hidrojen peroksit (H₂O₂) ve hidroksil radikalleri (.OH) gibi reaktif oksijen türlerini oluşturur. Sitotoksik türler hücrede oksidatif hasara neden olabilir. Nitekim yaşlılık bu oksidatif değişikliklerin birikimi ile ilgili geri dönüşümsüz hasarların bir işleyişi olarak düşünülebilir. Yaşlanma olayında antioksidan enzim aktivitelerinin arttığı ya da azaldığı belirtilmektedir. Birçok araştırmaya göre yaşlı dokularda yaşlanma sırasında yüksek oranlarda üretilebilen serbest radikallere karşı etkili bir antioksidan savunma sağlayan bazı düzenleyici mekanizmalar vardır. Yaşlılığın primer nedeninin okside moleküller olduğu hakkında kesin delil yoktur. Yaşlanma muhtemelen çok yönlü bir olaydır ve herhangi bir tek nedene indirgenemez.

Anahtar kelimeler: Yaşlanma, serbest oksijen radikalleri, antioksidanlar

 

 

THE ROLE OF FREE RADİCALS İN THE AGİNG PROCESS AND AVERAGE LİFE SPAN İN MAMMALS

ABSTRACT

Free oxygen radicals have been proposed as important causative agents of aging. In this review, the relationship between antioxidant protection and life span, the effects of reduced oxidative damage on the life span and the effects of dietary manipulations on ageing and free radical damage were discussed. The main source of the free radicals is molecular oxygen. The univalent reduction of molecular oxygen results in reactive oxygen species (ROS) such as superoxide dismutase anions (O₂-), hydrogen peroxide (H₂O₂) and hydroxyl radicals (OH). The cytotoxic species can cause oxidative damage in the cell. Aging can thus be viewed as a process of irreversible injuries associated with accumulation of these oxidative changes. Activity of antioxidant enzymes has been reported to either increase or decrease in the aging process. According to many studies there are some regulatory mechanisms in senescent tissues to provide an efficient antioxidant defence against free radicals, which may be generated at a higher rate during the aging process. Definitive proof that oxidized molecules are the primary cause of ageing is lacking. Aging is also likely to be a multifactorial process and not reducible to any one single cause.

Key words: Aging, free oxygen radicals, antioxidants.

 

Anahtar Kelimeler

Yaşlanma, serbest oksijen radikalleri, antioksidanlar

Kaynakça

• Agarwal, S., Sohal, R.S.: DNA oxidative damage and life expectancy in hause flies. Proceding of the National Academy of Science, 1994; 91: 12332–12335.
• Ali, SS., Xiong, C., Lucero, J., Behrens, MM., Dugan, LL., Quick, KL.: Gender differences in free radical homeostasis during aging: Shorter- lived female C57BL6 mice have increased oxidative stres. Aging Cell, 2006; 5 (6): 565–574.
• Ames, B.N., Shigenaga, M.K., Hagen, T.M.: Oxidants, antioxidants, and the degenerative diseases of aging. Proceding of the National Academy of Science, 1993; 90: 7915–7922.
• Barouki, R.: Ageing free radicals and cellular stres. Medicine Science, 2006; 22 (3): 266– 272.
• Chakravarti, B., Chakravarti, DN.: Oxidative modification of proteins: Age-related changes. Gerontology, 2006; 53 (3): 128–139.
• Chance, B., Sies, H., Boveris, A.: Hyperperoxide metabolism in mammalian organs. Physiology Review, 1979; 59: 527–603.
• Cutler, R.G.: Antioxidants and longevity. In: Free radicals in molecular biology, aging and disease. Ed. Armstrong, D., Sohal, R.S., Cutler, R.G., Slater,T.F. New York, Raven Pres,1984, 235-266.
• Frank, L.:Oxygen toxicity in eukaryotes. In: Superoxide dismutase, pathological states. Ed.Oberly, L.W. Boca Raton, CRC Pres, 1985, 3: 1–43.
• Halliwell, B., Gutteridge, J.M.: Free radicals in biology and medicine. Second ed, Oxford, Oxford University Pres, 1989.
• Harman, D.: Free radical theory of aging : History. In: Free radicals and aging. Ed. Emerit, I., Chance, B. Birkhauser-Verlag, Basel, 1992, 1-10.
• Lee, D.W., Yu, B.P.: Modulation of free radicals and superoxide dismutase by age and dietary restriction. Aging, 1990; 2: 357–362.
• Lippman, R.D.: Lipid peroxidation and metabolism in aging. In: review of biological research in aging. Ed. Rothstein, M. New York, Alan R. Liss, 1983, 1: 315–342.
• Mc Cay, C., Crowell, M., Maynard, L.: The effect of retarded growth upon the length of life and upon ultimate size. Journal Nutrition, 1935; 10: 63–79.
• Pamplona, R., Barja, G.: Mitochondrial oxidative stres, aging and caloric restriction:The protein and methionine connection. Biochimica et Biophysica Acta, 2006;1757 (5–6): 496– 508.
• Randerath, K., Randerath, E., Filburn, C.: Handbook of the biology of aging. In: Ed. Schneider, E.L., Rowe J.W. San Diego, Academic Pres, 4th ed , 1995, 198-216.
• Sacher, G.A.: Life table modification and life prolongation. In: Handbook of the biology of aging. Ed. Finch, C.E., Hayflick, L. New York, Van Nostrand, 1977, 582-638.
• Sohal, R.S., Farmer, K.J., Allen, R.G., Cohen, N.R.: Effect of age on oxygen consumption, superoxide dismutase, catalase, glutathione, inorganic peroxides and chloroform-soluble antioxidants in the adult male hausefly, Musca domestica. Mechanisms of Ageing Development, 1984; 16: 159–167.
• Sohal, R.S., Toy, P.L., Farmer, K.J.: Relationship between life expectancy, endogenous antioxidants and products of oxygen free radical reactions in the hausefly, Musca domestica. Mechanisms of Ageing Development, 1986; 36: 71–77.
• Sohal, R.S.: The free radical theory of aging : A critique. In: review of biological research in aging. Ed. Rothstein, M. New York, Alan R. Liss, 1987, 3: 431–449.
• Sohal, R.S., Sohal, B.H., Brunk, U.T.: Relationship between antioxidant defences and longevity in different mammalian species. Mechanisms of Ageing Development, 1990; 53: 217–227.
• Sohal, R.S., Weindruch, R.: Oxidative stres, caloric restriction, and aging. Science, 1996; 273: 59–63.
• Sohal, R.S.: Role of oxidative stres and protein oxidation in the aging process. Free Radical Biology and Medicine, 2002; 33 (1): 37–44.
• Stadtman, ER.: Protein oxidation and aging. Free Radical Research, 2006; 40 (12): 1250– 1258.
• Tolmasoff, J.M., Ono, T., Cutler, R.G.: Superoxide dismutase: correlation with life span and specific metabolic rate in primate species. Proceding of the National Academy of Science, 1980; 77: 2777–2781.
• Voss, P., Siems, W.: Clinical oxidation parameters of aging. Free Radical Research, 2006; 40 (12): 1339–49.
• Weindruch, R., Walford, R.: The reduction of aging and disease by dietary restriction. Ed. Charles C. Thomas, St Louis, 1988.
• Weindruch, R., Sohal, R.S.: Caloric intake and aging. The New England Journal of Medicine, 1997; 337: 986–994.
• Wickens, A.P.:Ageing and the free fadical theory. Respiration Physiology, 2001; 128: 379– 391.
• Widmer, R., Ziaja, I., Grune, T.: Protein oxidation and degradation during aging: Role in skin aging and neurodegeneration. Free Radical Research, 2006; 40 (12):1259–68.
• Yu, B.P.: Modulation of aging processes by dietary restriction. Ed. Yu, B.P. Boca Raton, CRC Pres, 1994.