RESUMO
During liver surgery and liver transplantaion, ischemia-reperfusion [I/R] is an unavoidable and major unresolved problem. Therefore, various pharmacologic approaches to prevent hepatic I/R injury are currently under trial. In this study, thymoquinone [TQ], the active constituent of Nigella sativa seeds which has an antioxidant activity was investigated. Rats were classified into three groups. Group 1 served as control group [Sham operated]. In the 2[nd] and 3[rd] groups, the hepatic artery and portal vein were occluded. Rats in the 3[rd] group received TQ [50 mg/kg dissolved in corn oil orally] half an hour before occlusion. Asparatate aminotranferase [AST] and alanine aminotransferase [ALT] activities were measured in serum of blood samples taken from the canulataed carotid artery. Lipid peroxides content, superoxide dismutase [SOD] and DT-diaphorase activities were measured in liver homogenate. Pathological changes were assessed using hematoxylin and eosin [H and E] and periodic acid-Schiff [PAS] stains. There was marked elevation in the activities of serum AST and ALT in the non treated group compared to the control group, while in the treated group, there was significant decrease compared to the non-treated group. Also, in liver homogenate,;lipid peroxides content was significantly elevated in the non treated group [group 2] compared to the control group [group 1], while in the treated group [group 3], lipid peroxides content decreased significantly compared to the non-treated group [group 2]. SOD and DT-diaphorase were TQ treated group [3], there were significant increase compared to non-treated group [2]. The histopathological results showed dilation and hemorrhage in central vein and reduction in reaction of mucopolysachride in hepatocytes in non-treated group. These pathological changes significantly improved in TQ treated group [group 3]. The results suggest that thymoquinone is a beneficial protective agent against ischemia-reperfusion induced hepatic injury, an action that might be mediated through its antioxidant effect