Radiation-induced neurocognitive impairments: prophylactic role of antioxidants

Radiation-induced oxidative stress has been implicated in cognitive impairments in experimental animals. Over the last many years, much evidence has been gathered showing that enhanced free radical levels and an impaired antioxidant pool are important factors underlying the pathophysiological mechanisms in a variety of neurodegenerative diseases. Reactive oxygen species (ROS) are produced in the course of normal as well as aberrant metabolic processes and they serve important physiological functions. However, because of their high reactivity, accumulation of ROS beyond the immediate needs of the cell may affect cellular structure and functional integrity, by bringing about oxidative degradation of critical molecules, such as the DNA, proteins, and lipids. Although cells possess an intricate network of defense mechanisms to neutralize excess ROS and reduce oxidative stress, some tissues, especially the brain, are much more vulnerable to oxidative stress