Oxidative stress and antioxidant defence in cirrhotic patients associated with spontaneous bacterial peritonitis

Reactive species include reactive oxygen species and reactive nitrogen species. They are unstable chemicals generated in biologic systems under normal physiological as well as pathophysiological conditions in the liver of cirrhotic patients. Spontaneous bacterial peritonitis (SBP) is the most common complication of liver cirrhosis and accounts for significant mortality. SBP is associated with an important production of proinflammatory cytokines essential for an adequate host response against infection. The aim of the present study was to assess the state of oxidative stress, lipid peroxidation and nitric oxide levels as well as TNF-α mRNA expression level in sterile cirrhotic patients and others accompanied with spontaneous bacterial peritonitis in response to the treatment. Nitric oxide and Malondialdehyde were measured in ascitic fluid. Superoxide dismutase and glutathione peroxidase were measured in erythrocyte lysate and catalase activity in serum. RT-PCR was used to assess the expression of TNF-α mRNA in duodenal biopsy. These parameters were assayed in non-infected cirrhotic patients (n=10) and patients with SBP before and after treatment (n=20). In addition a group of healthy volunteers with matched age and sex (n=10) was involved in the study as a control group. oxidative stress is demonstrated by increased MDA accumulation and reduced glutathione peroxidase and superoxide dismutase as well as serum catalase. A significant elevated base line of TNF-α mRNA expression level in SBP ascitic fluid (254.019±26.471, 2740±247.81, 9395±1242.779 respectively) (P<0.001). In addition to the increased concentration of NO level in patients with SBP but not in patients with sterile ascites (74.237±4.309, 40.537±3.625 respectively) (P<0.001). A notable positive significant correlation between TNF-α expression level and NO (P<0.001) among the three studied groups. After antibiotic treatment MDA, NO and TNF-α expression levels dropped back towards sterile values. In the mean time, antioxidant elements were also recovered. This study demonstrates that overproduction of NO, MDA and TNF-α expression levels may be used as markers for diagnosing SBP and a useful index in determining therapeutic response to antibiotic treatment. In addition to the down regulation of antioxidant defence elements in sterile cirrhotic patients predicting the development of complications such as SBP. © 2009, INSInet Publication.