Oxidative stress and its impacts on intracellular lipids, proteins and DNA

Abstract

Oxidative stress is described as disturbed oxidative balance between increased reactive oxygen species such as hydroxyl radical (OH•), superoxide radical (O 2 −), hydrogen peroxide (H 2 O 2) which occurs during normal cellular metabolism and decreased antioxidants which have scavenging effects on free radicals. Reactive oxygen species resulted from increased oxidative stress attacks on to the double bonds of lipids, proteins and DNA bases, removing one hydrogen atom from structure and initiate to oxidative chain reactions. This process leads to cellular damage and death damaging intracellular macromolecules such as lipids, proteins and DNA. The damage of free radicals is detected measuring oxidative products such as malondialdehyde (MDA), protein carbonyl (PCO) and 8-hydroxyguanine derivatives (8-OHG, 8-hidroksi-2′deoksiguanozin) in body fluids and various tissues. Although considerable amount of studies in this field, the effects of oxidative stress on cellular structures still remain unknown. In this review, we aimed to evaluate the biochemical aspects of oxidative stress, antioxidant systems and their mechanism of actions and oxidative products.

Assessment of Oxidative Status in Foot Diseases of Sheep

“…In the presence of various stress factors, the level of malondialdehyde (MDA), the end product of lipid peroxidation, increases [3]. MDA is one of the most important biochemical markers used to determine the degree of cellular damage in tissues [20,23]. The level of MDA has been reported to increase in studies conducted with cattle with foot-and-mouth disease [12,17] and with calves with different inflammatory diseases such as arthritis and omphalitis [5,31].…”

“…Several defense mechanisms have been developed in organisms to prevent the damage on the cellular structure caused by free radicals, more specifically the ROS (Reactive Oxygen Species), and these mechanisms are called antioxidant defense systems [20].…”

Oxidative Stress Levels of Serum and Urine in Enuresis

“…Bu sonuçlar bize hem Komplike NE hem de Basit NE grubunda yani enürezisde idrar oksidatif stres yükünün arttığını göstermektedir. Oksidatif stres, başta kanser olmak üzere diyabet, kardiyovasküler ve nörolojik hastalıklar, ateroskleroz ve inflamatuvar bozukluklar gibi birçok hastalığın patogenezinden sorumludur (6). Bu nedenle enureziste artan idrar oksidatif stresin önemli olduğunu düşünüyoruz.…”

The thiol-disulfide balance in smokers and non-smokers

“…Tobacco smoke contains high levels of free radicals and other oxidants, in addition to toxins and carcinogens [1], and is an important risk factor in the development of pathological conditions such as chronic obstructive pulmonary disease [2], lung cancer [3] and coronary heart disease [4]. Smoking increases oxidative stress both through the increased production of free radicals and the weakening of the antioxidant defense systems [5,6] and so leads to oxidative damage to such biological structures as nucleic acids, lipids and proteins [7]. Thiols are organic molecules containing a sulfhydryl group (-SH) that play crucial roles in the defense mechanism against oxidative stress [8].…”