MEMELİLERDE ORTALAMA YAŞAM SÜRESİ VE YAŞLANMA SÜRECİNDE SERBEST RADİKALLERİN ROLÜ

Year 2007, Volume: 33 Issue: 1, 43 - 49, 26.11.2012

Sema Yaralıoğlu Gürgöze Tekin Şahin M. Durak

Abstract

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.

 

Keywords

Yaşlanma, serbest oksijen radikalleri, antioksidanlar

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