Nigella Sativa and Thymoquinone Suppress Cyclooxygenase-2 and Oxidative Stress in Pancreatic Tissue of Streptozotocin-Induced Diabetic Rats

Objective: The aim of this study was to investigate the effect of Nigella sativa and thymoquinone (TQ) on oxidative stress, cyclooxygenase-2 (COX-2), and intracellular adhesion molecule-1 mRNA expression in the pancreas of streptozotocin (STZ)-induced diabetic rats as a model of type 1 diabetes. Methods: Five experimental groups including control group, STZ-induced diabetic group, aqueous extract diabetic treated group, oil diabetic treated group, and TQ diabetic treated group were used to obtain the pancreatic tissue samples and serum for investigation. Results: A significant increase in COX-2 mRNA expression was detected in STZ-induced diabetic group after 10 days of diabetes induction indicating an important role of the enzyme COX-2 in the inflammation accompanying STZ diabetes in contrast to that detected for intracellular adhesion molecule-1. Treatment of STZ diabetic rats with N. sativa aqueous extract and TQ significantly suppressed the expression of COX-2 enzyme in the pancreatic tissue. Nigella sativa and TQ treatment also suppressed pancreatic tissue lipid peroxidation malondialdehyde levels and increased the level of superoxide dismutase antioxidant enzyme correlated with the decrease in COX-2 mRNA expression. Conclusions: Results obtained in this study support a potential role for N. sativa and TQ in ameliorating inflammation during diabetes and preserving beta cells.