The brain tissue is sensitive to oxidative imbalance and previous studies have demonstrated that oxidative injury plays a key role in the pathogenesis of numerous neurodegenerative diseases including stroke, Alzheimers disease and vascular dementia (Chung et al., 2005; Coyle and Puttfarcken, 1993). Oxidative stress is defhed as the imbalance between oxidants and antioxidants in favor of oxidant activity that potentially leads to tissue damage (Polidori et al., 2000). Oxidative metabolism of the brain tissue is high and the large lipid content of myelin is a special target of reactive oxygen species (ROS) (Choi, 1993). Enzymes like superoxide dismutase (SOD), catalase and glutathione peroxidase, as well as non-enzymatic antioxidants (as, for example, glutathione, ascorbate and tocopherol) (Halliwell, 1992), may play a protective role in the development of lesions caused by chronic cerebral hypoperfusion in the central nervous system (Markesbery, 1997), due to their ability to react with free radicals(Atmaca, 2004; Sen et al., 1998).