title: The Radioprotective Effects of Caffeic Acid Phenethyl Ester and Thymoquinone on Oxidative and Nitrosative Stress in Liver Tissue of Rats Exposed to Total Head Irradiation.
abstract: OBJECTIVE
  The aim of this study is to investigate the effects of addition of caffeic acid phenethyl ester (CAPE) and thymoquinone (TQ) on oxidative and nitrosative stress in the liver tissue of irradiated rats.
  
  
  METHODS
  Forty Sprague-Dawley rats were divided into five groups to test the radioprotective effectiveness of TQ and CAPE administered by intraperitoneal injection. Appropriate control groups were also studied.
  
  
  RESULTS
  Liver antioxidant capacity, as measured by levels of total superoxide scavenger activity (TSSA), non-enzymatic superoxide scavenger activity (NSSA) and glutathione-S-transferase (GST) activity except superoxide dismutase (SOD) activity, were statistically lower in the irradiation (IR) group compared to all other groups. Total superoxide scavenger activity and NSSA were statistically higher in the IR plus TQ and IR plus CAPE groups compared to all other groups. In contrast, glutathione peroxidase (GSH-Px) activity was significantly found to increase in the IR plus CAPE group compared to control groups. The xanthine oxidase (XO), nitric oxide synthase (NOS) activities, nitric oxide (NO●) and malondialdehyde (MDA) levels in the IR group were statistically higher than in the other groups. Moreover, XO activity in the IR plus TQ group was statistically lower than all other groups including the IR plus CAPE group. In addition, NO●level was found to increase in all groups when compared to the normal control group.
  
  
  CONCLUSIONS
  Thymoquinone and CAPE decrease oxidative and nitrosative stress markers and have antioxidant effects, which also increase antioxidant capacity in the liver tissue of irradiated rats.
authors.affiliation: Department of General Surgery, Faculty of Medicine, Canakkale 18 March University, Canakkale, Turkey.
authors.forename: O
authors.initials: O
authors.lastname: Cikman
authors.affiliation: Department of Medical Biochemistry, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey. e-mail: seytaysi@hotmail.com.
authors.forename: S
authors.initials: S
authors.lastname: Taysi
authors.affiliation: Department of Gastroenterology, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: M T
authors.initials: MT
authors.lastname: Gulsen
authors.affiliation: Department of Medical Biochemistry, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: E
authors.initials: E
authors.lastname: Demir
authors.affiliation: Department of Medical Biochemistry, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Akan
authors.affiliation: Department of Medical Biochemistry, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: H
authors.initials: H
authors.lastname: Diril
authors.affiliation: Department of Anesthesiology, Faculty of Medicine, Canakkale 18 March University, Canakkale, Turkey.
authors.forename: H A
authors.initials: HA
authors.lastname: Kiraz
authors.affiliation: Department of General Surgery, Faculty of Medicine, Canakkale 18 March University, Canakkale, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Karaayvaz
authors.affiliation: Department of Medical Biochemistry, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Tarakcioglu
keywords: Antioxidant; caffeic acid phenethyl ester; free radicals; irradiation; thymoquinone