Effect of Nigella sativa L. and Thymoquinone on Streptozotocin Induced Cellular Damage in Pancreatic Islets of Rats

摘要

The aim of the study was to investigate the role of aqueous extract of Nigella sativa seed, Nigella sativa oil and thymoquinone in ameliorating the cellular damage produced in pancreatic cells by streptozotocin (STZ). Five equal sized groups of male Sprague-Dawley rats were used in this study. The groups included; control, STZ induced diabetic, STZ diabetic-aqueous extract treated (2 mL kg~(-1)), STZ diabetic-oil treated (0.2 mL kg~(-1)) and STZ diabetic-thymoquinone treated (5 mg kg~(-1)) groups. After 30 days of treatment, pancreatic tissues of the different groups were examined by the light and transmission electron microscope. The aqueous extract of N sativa reduced some of the cellular damage caused by STZ on beta cells. In contrast, the use of its oil exacerbated the destructive effect of STZ. The use of thymoquinone; the active ingredient of N. sativa, ameliorated the toxic effects of STZ on pancreatic beta cells. The nuclear alterations observed including segregated nucleoli, marginatingaggregates of heterochromatin and decreased heterochromatin indicate DNA damage in STZ-treated rats and are consequently responsible for the development of type 1 diabetes. The present study emphasizes that N sativa extracts are effective in reducing the cellular damage caused by STZ. In addition, findings suggest that the active ingredient thymoquinone is the most effective against STZ diabetes as its administration ameliorated most of the pathological changes. This could be attributed to the antioxidant properties of N. sativa and thymoquinone that inhibit the cellular damage caused by STZ in pancreatic cells.