Nigella sativa protects against ischaemia/reperfusion injury in rat kidneys

Background: Renal ischaemia followed by reperfusion leads to acute renal failure in both native kidneys and renal allografts, which is a complex pathophysiologic process involving hypoxia and free radical (FR) damage. The oil of Nigella sativa (NSO) has been subjected to considerable pharmacological investigations that have revealed its antioxidant activity in different conditions. But there is no previously reported study about its effect on ischaemia/reperfusion (I/R) injury of kidneys. The aim of this study was to investigate the possible effects of NSO in I/R-induced renal injury in rats. Methods: Thirty healthy male Wistar albino rats were randomly assigned to one of the following groups: control, sham, I/R, NSO+I/R, I/R+NSO and NSO. I/R, NSO+I/R and I/R+NSO rats were subjected to bilateral renal ischaemia followed by reperfusion and then all the rats were killed and kidney function tests, serum and tissue oxidants and antioxidants were determined and histopathological examinations were performed. Results: Pre- and post-treatment with NSO produced reduction in serum levels of blood urea nitrogen (BUN) and creatinine caused by I/R and significantly improved serum enzymatic activities of superoxide dismutase (SOD) and glutathion peroxidase (GSH-Px) and also tissue enzymatic activities of catalase (CAT), SOD and GSH-Px. NSO treatment resulted in lower total oxidant status (TOS) and higher total antioxidant capacity (TAC) levels and also significant reduction in serum and tissue malondialdehyde (MDA), nitric oxide (NO) and protein carbonyl content (PCC) that were increased by renal I/R injury. The kidneys of untreated ischaemic rats had a higher histopathological score, while treatment with NSO nearly preserved the normal morphology of the kidney. Conclusions: In view of previous observations and our data, with the potent FR scavenger and antioxidant properties, NSO seems to be a highly promising agent for protecting tissues from oxidative damage and preventing organ damage due to renal I/R.