The Radio-protective effects of Caffeic Acid Phenethyl Ester and Thymoquinone in rats exposed to total head irradiation

Many cancer patients treated with radiotherapy suffer severe side effects during and after their treatment. The aim of this study was to investigate the effects of irradiation and the addition of caffeic acid phenethyl ester (CAPE) and thymoquinone (TQ) on the oxidant/antioxidant system in the liver tissue of irradiated rats. A total of 40 Sprague-Dawley rats were divided into five groups to test the radioprotective effectiveness of thymoquinone and caffeic acid phenethyl ester administered by intraperitoneal injection. Appropriate control groups were also studied. While liver tissue total oxidant status, lipid hydroperoxide level, and oxidative stress index were significantly increased in the irradiated (IR) group, compared with other groups, total antioxidant status, sulfhydryl levels, and paraoxonase (PON) activity were significantly decreased. Ceruloplasmin activity in IR plus TQ and IR groups was higher than the control group. Arylesterase and PON activities in IR plus TQ- and IR plus CAPE-supplemented groups were lower than those of control groups. TQ and CAPE decrease oxidative stress markers and have antioxidant effects, which also augment antioxidant capacity in the liver tissue of irradiated rats.