الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), is a chronic relapsing disease of the gastrointestinal tract with progressive course, with increasing incidence and prevalence worldwide. It affects patients’ quality of life badly. Moreover, the exact etiology of UC is still a matter of debate. However, it is suggested that it is due to interactions between environmental, genetic, microbial and immunological factors. These interactions are suggested to result in proinflammatory cytokines overproduction with subsequent increased levels of ROS. These proinflammatory cytokines, such as tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN- γ) are produced in excess in UC patients, inducing reactive oxygen species (ROS) production.
Oxidative stress (OS) is suggested to have a pivotal role in UC pathogenesis. It was reported that UC was associated with imbalance between ROS and antioxidant capacity resulting in OS due to either increased production of ROS or decreased antioxidant capacity.
Oxidation reactions are vital for aerobic life; however, uncontrolled ROS production is damaging. Meanwhile, the body is equipped by antioxidant defense system, that includes enzymatic antioxidants as (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)) and nonenzymatic ones as (glutathione, bilirubin, zinc and selenium). But ROS overproduction could consume that antioxidant defense system.
Superoxide dismutase (SOD) is an antioxidant enzyme which protects cells against OS by converting superoxide anion into easily diffusable hydrogen peroxide, which is then neutralized into oxygen and water and it can reduce the production of some proinflammatory cytokines. Under inflammatory conditions, its level is found to be decreased.
Malondialdehyde (MDA) is one of the major aldehydes, which is produced as a result of lipid peroxidation, which is a consequence of OS. It is frequently used as a biomarker of lipid peroxidation and an index of oxidative status.