Oxidative stress

Oxidative Stress

Oxidative stress is a phenomenon caused by an imbalance between production and accumulation of oxygen reactive species (ROS) in cells and tissues and the ability of a biological system to detoxify these reactive products.

Overview

ROS are produced as a normal product of cellular metabolism. In particular, the majority of ROS are produced in the mitochondria of cells during the process of electron transport, oxidative phosphorylation, and reduction of molecular oxygen.

Causes

Oxidative stress is caused by an imbalance between the production of reactive oxygen and a biological system's ability to readily detoxify the reactive intermediates or easily repair the resulting damage. This imbalance can be due to either an excess production of ROS or a decrease in antioxidant defenses.

Effects

The effects of oxidative stress depend upon the size of these changes, with a cell being able to overcome small perturbations and regain its original state. However, more severe oxidative stress can cause cell death and even moderate oxidation can trigger apoptosis, while more intense stresses may cause necrosis.

Role in Disease

Oxidative stress is thought to contribute to the development of a wide range of diseases including Alzheimer's disease, Parkinson's disease, the pathologies caused by diabetes, rheumatoid arthritis, and neurodegeneration in motor neuron diseases.

See Also

• Antioxidant
• Free-radical theory
• Reactive oxygen species
• Mitochondrion

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