Radioprotective effect of thymoquinone on salivary gland of rats exposed to total cranial irradiation

Background: The purpose of this study was to investigate the radioprotective effects of thymoquinone against radiation-induced damage in the salivary glands of rats exposed to total cranial gamma irradiation. Methods: Thirty-two Sprague-Dawley rats were divided into 4 groups to test the radioprotective effectiveness of thymoquinone by intraperitoneal injection. An appropriate control group was also studied. Biochemical parameters in liver tissue of rats were determined by spectrophotometer. Results: Glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST), total (enzymatic plus nonenzymatic) superoxide scavenger activity (TSSA), nonenzymatic superoxide scavenger activity (NSSA), and superoxide dismutase (SOD) activities were significantly decreased, whereas xanthine oxidase, nitric oxide synthase activities, malondialdehyde, nitric oxide, and peroxynitrite levels were significantly increased in the irradiation group when compared to the control and sham control groups. Conclusion: Results showed that thymoquinone reduces oxidative and nitrosative stress parameters and has antioxidant effects and a free radical scavenging activity.